June Tips
Monthly tips are categorized by To-Dos, What to Plant, or Pests and Diseases. Scroll through the list to see items in each category. Also, refer to our list of tips useful for any month.
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1. To-do
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Weed Spotlight - Filaree
- You may have noticed a highly prolific, rosette-shaped weed lately. Filaree (Erodium spp.) plants start out as low growing plants that can form a dense mat in open areas. They create bright pink flowers that turn into angled seed pods resembling a stork's head and beak, giving the plant one of its common names: storksbill. The spiral-shaped seeds explode out from the plant in late spring, drill into the soil with changes in humidity, and germinate with next year's rains. Recommended control methods include hoeing, hand pulling, and several inches of organic mulch.More information: Filaree
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Support Your Vegetables
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More Information: Trellising, Staking, and Caging
- February, March, April, May, June -
Weed Spotlight - Spotted Spurge
- For more information: Spotted Spurge Management Guidelines
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Drought Tip - No Fertilizer
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More information: Skip fertilizing
- May, June, July, August -
Testing Soil Moisture Depth
- You know how long you water your garden, but do you know how deep the water is going? You don’t need an expensive moisture meter to check. A simple probe can help you find out. Use any item sturdy enough to push a foot or so into the soil, for example, a long screwdriver or metal rod. Push the probe directly into the soil using firm pressure. It will go through moist soil and stop when it hits the underlying dry soil, showing you how deep your water has penetrated. Watering deeply but infrequently is recommended.
More information: Checking Moisture Depth
- June, July, August -
Protect Native Bees
- You probably see non-native honeybees in your garden, but do you know there are over 1600 species of native bees in California? These bees don’t make honey, don’t live in hives (most live right in the ground), and are much less likely to sting since they have no colonies to defend. Research shows some species pollinate crops twice as effectively as honeybees, plus they’re best suited to pollinate native plants. But like honeybees, they’re threatened by pesticides and loss of habitat. Help preserve these species by growing a variety of plants that flower at different times of the year and by keeping areas of open ground in your yard.
More information: Native Bees and Their Favorite Plants
Native Bee images, clockwise from top left: Leafcutter bee (Jim McCulloch), carpenter bee (Kathy Keatley Garvey), long-horned bee (Kathy Keatley Garvey), sweat bee (Missouri Department of Conservation Staff)
- March, April, May, June, July, August -
Pinching Flowers and Herbs
- More Information: Pinching Flowers and Herbs
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Pinch Your Basil
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More information: Basil Care
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Eliminating Perennial Weeds
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To control perennial weeds, repeatedly cultivate soil in summer and, when possible, keep the soil completely dry for several months to dehydrate weed stems, rhizomes, or tubers.
- June, July, August -
Drought Tips - Vegetable Gardening
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- Plant only as much as you can use. Produce that isn’t harvested wastes water.
- Plant in groups or triangular patterns rather than straight rows. This lets you water more efficiently, and the plants form a leafy canopy that shades the soil.
- Mulch, mulch, mulch to decrease moisture loss and reduce competition from weeds.
For more information: Ten Tips for Vegetable Gardening during a Drought
- May, June, July, August -
Fruit Thinning
- More Information: Thinning Young Fruit
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Fresh Fruits and Vegetables Without a Garden!
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If you like the freshest possible produce but don't have the space or time to grow your own, find a certified Farmers Market selling directly to consumers. The County of Santa Clara website has a Farmers Market page with links to certified Farmers Markets.
- June, July, August, September -
Water the Roots, Not the Plants
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It's tempting to get the hose out and spray your dry, thirsty plants, but you don't want to waste water. Keep their feet nice and cool, but resist the urge to squirt the leaves unless they need a cleaning (for dust or white fly for instance).
It's a common belief that daytime water on the leaves will burn them. While it's possible, according to scientists—for hairy leafed plants where water droplets are held above the leaf surface—but not very likely. It's more the water will simply evaporate and not do your plants much good and could encourage fungal pathogens if wet overnight.
- June, July, August -
Tomato Bottom Scarring
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Sometimes scarring can be seen on the bottom (blossom end) of tomatoes. This can be caused by weather conditions such as cool and cloudy weather at bloom time, making the blossom stick longer to the small fruit. The fruit is perfectly good to eat with the damaged part cut out. Some large heirloom tomatoes are more susceptible to this condition.
Also known as catfacing.
- June, July, August -
Container Color Choice
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If you are growing plants in containers, keep in mind that light colors do a better job at reflecting the sun. This helps keep the soil from drying out too quickly and reduces the chances of the roots burning. If you already have dark pots, consider painting them a lighter color, or be especially careful about watering.
- April, May, June, July -
Encouraging Dahlia Blooms
- First, make sure those tall flowers have support so they don’t flop over or break off. Disbudding—removal of all but the central bud on each stalk—will result in larger more spectacular flowers. Deadheading—cutting the spent flowers back to one node below the bloom before they can set seeds—will encourage lateral blooms. Water the plants regularly, and continue to apply low nitrogen fertilizer throughout the summer.Fundamentals of Growing Dahlias , American Dahlia Society
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Broccoli - Multiple Harvests
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More Information: Growing Broccoli
- March, April, May, June, September, October, November, December -
Vegetable Garden Check-In
- This is a good time in the season to evaluate your vegetable garden to see what’s producing well, what you can improve, and what to give up on and chalk up to experience. Take notes! If a plant is barely growing, could it benefit from a shot of fertilizer or some extra water? Might you have planted it out too early in a cooler-than-usual spring when both daytime and nighttime temperatures were still too cool? If it’s not getting six to eight hours of sun per day, can you move it to another spot or put reflective material nearby to give extra sunlight? Did you use a new soil that perhaps had a different blend of materials? Is part of it being eaten or affected by the disease? Observe closely, including on the underside of leaves and at night. Harvest regularly and promptly. And remember the old gardening adage, “There’s always next year.”
More information: Vegetable Diagnostic
- June, July -
Drought Tip - Irrigate Efficiently
- Water restrictions are being put into place all over the state due to the current drought. With over half of urban water used in landscapes, it is essential to make sure your irrigation system is efficient. Watch your plants for signs of underwatering, overwatering, or uneven watering. Consider reducing irrigation times. And make sure your water bill hasn’t unexpectedly jumped. Also, adjust systems on timers monthly as the weather changes or use an automatically-adjusting smart controller. A smart controller can make the needed adjustments after initial programming with plant, location, and other relevant information. Our Santa Clara County clay soil absorbs water slowly, so only water for a few minutes at a time to avoid runoff. Then repeat until the water penetrates to the depth of the roots. Inspect drip and sprinkler systems regularly to make sure there are no leaks, emitters are not clogged and it is watering the plants and not the sidewalk, also make sure the water is going to the root zones of the plants. If you run a hose to a plant, set a kitchen or cell phone timer so you don’t forget that the water is running. Valley Water can help residents with Water Wise Outdoor Surveys and Landscape Rebate Programs.
More information: Irrigation System Audit
- March, April, May, June, July, August, September, Any month -
Drought Tip - Lawns
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More information: Drought Resources
- March, April, May, June, July, August, September, Any month -
Transplanting Vegetables
- More information: Vegetable Planting Handbook (Los Angeles Master Gardeners)
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Garden Planning in a Drought
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More information: Drought: Gardening Tips
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Water Budgeting
- We always need to use water wisely. Sometimes it is necessary to stop and think about your landscape and prioritize water use. Trees are a long-term investment, yet mature trees may have extensive root systems enabling them to find enough water on their own. Fruit trees may need watering approximately monthly during the summer in order to produce good fruit. Vegetables should always be given adequate water in order to fulfill their purpose in the garden; otherwise the little bit of water you used will have been wasted if the garden is not feeding you well. It’s helpful to understand that home-grown vegetables use much less water overall than ones purchased at the store. Established flowering shrubs, especially California natives, tend to need less water than annual flowers and maybe a more water-efficient way to have color and beauty in your garden. Lastly, keep the weeds under control so that they don’t rob water from the plants that you actually want.More Information: Water Use Classification of Landscape Species (WUCOLS)
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Direct Seeding
- Some of the larger summer vegetables can be planted from seed directly into the garden this month. These include watermelon, cantaloupe, corn, and summer and winter squash. They tend to have larger seeds, and a rule of thumb is to plant them at a depth of two to three times the diameter of the seed. If you have a seed packet, follow instructions for planting depth, spacing, and thinning. These larger plants tend to grow quickly and out of the reach of many pests that impact small, tender, young seedlings. Amend and thoroughly water the soil before planting so that the seeds are not washed away with watering. Drop the seeds in holes and cover them with soil, or push them down into the soil. Then water again. Keep a close eye on emerging seedlings and protect them from pests as needed.More information: Planting Vegetable Seeds (Alameda County Master Gardeners)
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Prevent Fruit Tree Sun Burn
- More information: Care for Young Fruit Trees
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Soil Solarization
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Soil solarization can be used to control diseases, nematodes and weeds by baking everything under plastic sheeting.The best time for solarization of soil is from June to August. Transparent or clear plastic is the best choice. Leave the soil covered for 4 –6 weeks. Refer to the UC Pest Note on Soil Solarization for Gardens & Landscapes.
- June, July, August -
Tree Suckers and Waterspouts
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In order to keep your trees producing and growing efficiently, promptly remove any suckers coming from the roots, branches growing from beneath the graft union, and rapidly growing vertical shoots from the branches (waterspouts).
- June -
Keep Foliage after Bloom Fade
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If the plants seemed crowded and the flowers were getting smaller, carefully dig them up, separate the bulbs, and replant them with greater spacing. Toss any bulbs/corms/rhizomes/tubers
that are mushy or show other signs of rot. And continue to enjoy easy-maintenance flowers year after year. More information: Basic Bulb Care
- March, April, May, June -
Grass Cycling
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Leave the clippings on the lawn when mowing. This provides nitrogen for the lawn. Mow frequently so that no more than 1/3 of the length of the grass blade is cut in any one mowing. Grass decomposes rapidly and very little thatch is formed. Small amounts of thatch can actually be beneficial to a lawn, serving as a mulch. Many parks and golf courses have been doing this for years. Other uses for grass clippings include mulching for weed control and as a great addition to your compost pile. There are some cities that no longer will allow grass clippings in their dumps.
- June, July, August, September -
Worm Composting
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Worm composting, also called vermiculture or vermicomposting, is a convenient way to decompose kitchen waste and provide nutrient-rich soil amendments for your vegetable garden.
The Santa Clara County Home Composting Education Program offers:
- February, June, September -
Drip Irrigation
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- Water is placed more accurately and efficiently in the root zone, it is applied at a slow rate that reduces loss from runoff.
- Dry soil between plants allows you to work in the garden between irrigating.The key to success is watering long enough to supply adequate water to the root zone. Inappropriate watering commonly damages landscape plants. As with any irrigation system, they are efficient only when soil around the plants being irrigated is regularly monitored for proper moisture levels (Reference: UC Pest Note Poor Water Management, Poor Drainage).
- April, May, June, July, August, September, Any month -
Tomato Staking
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It's time to start planning how you will stake your tomatoes. You will want to stake your tomatoes right after you plant your seedlings. Here are the various Tomato Staking Techniques we have tried.
- April, May, June -
Geranium Care
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Geraniums need very little water. Too much water can lead to stem rot, or, if combined with too much fertilizer, more leaf growth than flowers. Geraniums prefer a dry location. If this isn't possible, try growing them in pots.
- June -
Citrus Fertilizing
- In California, most soils contain adequate nutrients for citrus growth, except nitrogen. Nitrogen is the primary nutrient required by the trees, and there are commercial fertilizers balanced specifically for citrus. One-year-old trees will need 1/10 of a pound of nitrogen, while mature trees need approximately 1-1/2 pounds. These amounts should be divided into two to three applications.
Blood meal without all the fillers is an excellent source of nitrogen, or you can purchase a balanced product that contains zinc. Spread the fertilizer evenly over the entire root area and water in.
For more information, refer to the UC Pest Note on Fertilizing Citrus, and Questions and Answers to Citrus Management from the UC Davis Home Orchard website.
- January, February, May, June -
Composting
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Composting is a good way to repurpose yard and kitchen waste, and it provides a free method to feed plants and improve soil structure. If you are unsure about how to begin composting, take a look at this simple how-to compost page. You can also go to the UCCE Composting Education Program website to learn more about free two-hour classes offered throughout the county.
As the weather warms up, compost piles dry out faster. Keep compost piles as damp as a wrung-out sponge to keep organisms alive and working on decomposing yard waste. Turning the pile to incorporate more oxygen also supports life in the compost pile.
- June, July, August, Any month -
Bee Swarms
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Bees are very active in warm weather. There is simply so much pollen and nectar to collect! Sometimes, a bee colony may swarm. If you see a swarm, don’t panic. As in any other time when working around bees, remain calm, move gently, and give them their space. Bees generally swarm when they are looking for a new home. Swarming bees are loaded with food and are not interested in stinging people. Contact the Bee Guild to have swarms removed.
- May, June, July -
Deadheading
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Deadheading means removing spent blossoms from your plants. Not all plants need deadheading, but if the flowers stay on the plant and become unattractive (think roses, dahlias, marigolds, coneflowers, geraniums and many more), then consider a little pruning. The technique varies by plant; some spent flowers can be snapped off by hand (dahlias), others are better done with hand pruners (roses), and some can be sheared off all together (lavender). You'll not only make the plant look better, you'll stimulate additional blooming for plants that have a long blooming season.
- May, June, July, August, September -
Drought Tip - Laundry to Landscape Irrigation
- A laundry to landscape system is an easy way to save water in times of drought. It can be installed easily at a low cost to send rinse water from clothes washers directly to the landscape.
Suitable plants include fruit and ornamental trees, shrubs, and ornamental annuals. It’s not applicable where the water would come in direct contact with fruits or vegetables.
More information: Laundry-to-Landscape Graywater System
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Fertilizing Ornamentals During Drought
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One way to manage plants during drought is to reduce the amount of fertilizer used. While plants need nutrients to survive and be healthy, excess fertilizer promotes additional growth, which then demands more water.
- May, June, July, August -
Watering Hydrophobic Soil
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Just as a dry sponge repels water, overly dry soil can do the same thing. This dried out soil is called hydrophobic. Hydrophobic soil can waste a lot of water as water drains away from the plant's root zone.
In pots: learn more about how to re-wet very dry soil on our Watering Hydrophobic Soil page. In the yard: setting sprinklers to run for 5 minutes, waiting for the water to soak in, and then running for a longer time can prevent water loss due to hydrophobic soil.
- May, June, July, August -
Lady Beetle
- We all know that lady beetles are good for the garden. Make sure you can recognize the larval stage because this life stage eats even more aphids than the adult form. Lady beetles lay their distinctive yellow eggs near a food source such as aphids. The larvae grow quickly, then pupate into the familiar adult form (but there are actually many varieties of lady beetles). It’s better to attract lady beetles to your garden rather than buying and releasing them. Purchased lady beetles generally fly away, and the process of collecting them in the wild is often destructive. To attract lady beetles, refrain from spraying insecticides, grow flowers that attract beneficial insects, and leave some aphids for them to eat.
For more information: Aphid Eaters
- March, April, May, June, July, August -
Soil Moisture Test
- How can you tell if your soil is moist enough?
- For trees or other landscaping, try pushing a soil probe or rod into the ground. When it stops going in, that shows how deeply water has penetrated. Irrigate until the water reaches 12 inches deep for grass, 12 to 18 inches for shrub and perennials, and 12 to 24 inches for trees.
- For garden beds or pots, use a trowel or simply stick your finger down into the soil a few inches to feel if it is moist or dry. Irrigate to keep the root zone moist.
- For smaller pots, you can often tell by lifting them if they need water. Well-watered pots will be heavy. Watch out for pots that have become hydrophobic, where the water runs through them without getting absorbed. They will need to be watered very slowly or soaked in a larger container to get rehydrated. See our tips for dealing with hydrophobic soil.
Remember that plant roots need air as well as water, so you want your soil to be moist but not soggy. -
Garlic Harvesting
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For more information: Garlic
- May, June, July -
Summer Vegetables
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More information: Vegetable gardening
- May, June, July, August, September -
Weed Spotlight - Bindweed
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For more information: Field Bindweed Pest Notes
- March, April, May, June, July, August, September, Any month
2. What to plant
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Tomatillo (Physalis philadelphica)
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Tomatillos still to this day is a truly wild plant. Attempts to hybridize them have failed. The plant is native to Mexico and was brought to the U.S. by Mexican Indian immigrants. It has a tart green apple taste and is the main ingredient in green salsas. It is also used in soups, stews, and guacamole.
It is a member of the Solanaceae (nightshade) family as is the tomato and will grow any place a tomato will. It is fairly drought tolerant. Being a wild plant, there is a great deal of variability in plant habit, fruit size, etc. It is an annual, a low growing, sprawling plant usually not more than 2 feet high.
The tomatillo has small, sticky, tomato-like fruits enclosed in papery husks. They are 1 to 3 inches in diameter and green or purplish in color. Culture is very similar to that for tomatoes or peppers. Plantings are generally direct seeded. The first harvest is ready in 70 - 80 days. They are not ripe until the fruit begins to break through the husk.
- June, July -
Attracting Bees
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Bees are pollination workhorses, increasing garden production. Many plants will not produce fruit unless flowers are pollinated. Colorful annuals, such as Cosmos, edible African Blue Basil, and Salvias attract bees. You can also allow herbs and other plants to flower to create bee-friendly landscapes.
The University of California at Davis has a garden dedicated to bees. The Honey Bee Haven website has more resources, including a list of plants they grow.
- March, April, May, June, September, October -
Nematode Control with Marigolds
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Some varieties of marigold can suppress certain damaging nematodes while adding color to the garden. The Tagetes species suppress root knot and lesion nematodes. French marigolds, including Nemagold, Petite Blanc, Queen Sophia, and Tangerine, are most effective. Avoid signet marigolds, T. signata or tenuifolia, because nematodes will feed and reproduce on these. Marigolds don’t work well against the northern root knot nematode, Meloidogyne hapla, a species common in areas with cool winters. The effect of marigolds is greatest when grown as a solid planting for an entire season. When grown along with annual vegetables or beneath trees or vines (intercropping), nematode control usually isn’t very effective. To prevent marigold seed from getting in the soil, cut or mow the plants before the flowers open. As with other cultural control methods, nematode populations rapidly will increase as soon as susceptible crops are grown again. Learn more at the UC Pest Note on Nematodes.
- June -
Growing Peppers
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As soon as average night time temperatures are above 55° F, peppers can be added to the garden. Before that time, they can be started indoors. Make pepper more productive by planting different varieties closely together. You will get more peppers per square foot because the plants support each other and provide protection from sunburn. Plus, they look lush and beautiful. After planting, it is a good idea to remove flowers and fruit from large-podded plants the first four to six weeks to encourage deeper roots and more foliage. Learn more pepper tips by consulting our Growing Great Peppers and Chiles page.
- May, June -
Asian Vegetables
- You can easily grow some vegetables used in different types of Asian cuisine and found in Asian markets. They are not necessarily native to Asia but have found their way into various cuisines. One way to decide which food to grow yourself is to choose varieties that aren't readily available or are more expensive in your local markets. It’s also fun to impress your family, friends, and neighbors with something they may not have seen growing before. Possibilities include sesame seeds, bitter melon, opo, sigua (loofah) in summer and bok choy, napa cabbage, daikon radishes, gai choy in spring or winter.
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Plants to Attract Butterflies
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Butterfly populations fluctuate in response to climate and habitat conditions. Many have specific host plants on which they feed and breed. Some common plants for attracting butterflies are milkweed, lantana, buddleia, and zinnias. For an extensive list of relationships between specific butterflies and host plants, see Art Shapiro's Butterfly Site at UC Davis.
- March, April, May, June -
Vegetable Planting Chart
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Wondering what vegetables can be planted now? To get the best success—whether planting from seed or transplants—refer to our Santa Clara County Vegetable Planting Chart. It's based on our own garden experiences.
- February, March, May, June, July, August, October, Any month -
Don't Plant an Invasive Plant
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According to PlantRight, so-called invasive plants "escape into open landscapes and cause a variety of ecological problems. They displace native plants and wildlife, increase wildfire and flood danger, clog valuable waterways, degrade recreational opportunities, and destroy productive range and timberlands."
PlantRight has identified the following as invasive in Northern California: Green fountain grass (Pennisetum setaceum), Periwinkle (Vinca major), Pampas grass (Cortaderia selloana), Highway iceplant (Carpobrotus edulis), Mexican feathergrass (Stipa / Nassella tenuissima), Yellow Flag Iris (Iris pseudacrorus), Water Hyacinth (Eichhornia crassipes).
With just a little research you can avoid using plants that are unfriendly to the Bay Area. -
High Yield Vegetables
- There are many considerations for choosing which edibles to plant in your garden. A particularly important one this year may be high yield. The more the plants produce, the more food you will have right on your property. Zucchini naturally comes to mind first. You may need to research additional recipes, and your neighbors may be more amenable this summer to having bags of zucchini dropped on their doorsteps during the night. Other plants that produce a lot are tomatoes and eggplant. Green beans need to be picked almost daily so they will give you an ongoing source of vegetables for a couple of months. Certain cucumbers like Persian cucumbers are eaten small and produce prolifically, enabling you to eat cucumbers more often than if you were waiting for full-size varieties. Vining plants, e.g., melons, will give you more to eat if grown on vertical supports rather than having the produce lie on the ground where it can be more readily eaten by pests.
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Fresh Cut Flowers from Your Garden
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More information: Tips on planting a cut flower garden
- January, February, March, April, May, June, Any month -
Chrysanthemums
- This is a less common but good time to plant chrysanthemums. They will have plenty of time to develop a good root system before the cold winter and are more likely to bloom perennially in your garden than if they are started in the fall. You can also start chrysanthemums from cuttings. Plant them in amended, well-drained soil, or grow them in a large container. Keep them moist but not wet. They do well in full sunshine, yet a little afternoon shade is fine in hot areas. If you pinch the growing tips as they grow, they will branch and be bushier. Otherwise, be prepared to provide support if they grow tall. Also, pinching off some of the buds will result in fewer yet much larger blooms. There is a Bay Area Chrysanthemum Society for local information and sharing.More Information: Chrysanthemum Disorders and Pests
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Thyme
- Thyme is much more than an herb to season food. In ancient times it was brewed by Egyptians for mummification, bathed in by Greek soldiers for courage in battle, and used by the Sumerians as an antiseptic and antifungal. And if you want a real surprise, check out the active ingredient list on a bottle of Listerine mouthwash. In your own garden it can be used for culinary purposes or as a purely ornamental landscape feature. It grows best in well-drained soil and sunshine, although it will tolerate some shade. It is quite drought tolerant once established. Common/garden thyme (Thymus vulgaris) is an excellent all-purpose thyme, growing to a foot tall and up to two feet wide. Lemon thyme (Thymus citriodorus), with its lemon scent, makes a nice evergreen border. Creeping thyme (Thymus serpyllum) stays short and can be used as a ground cover or between stepping stones. Thyme is attractive to butterflies and bees.More Information: Growing and Using Thyme
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Stone Fruit Hybrids
- Plant hybridization is the crossbreeding of different plant varieties. It can happen naturally but more often comes from deliberate work. A goal of hybridization is creating a new plant with the most desirable traits of its parents, such as the sweetness of a peach and the tartness of a plum. There are many different types of stone fruit hybrids. Here are some examples:
- Pluot and aprium: hybrids of a plum and an apricot, named for which fruit dominates.
- Plumcot: a 50–50 hybrid of a plum and an apricot.
- Peacotum: a hybrid of peach, apricot, and plum.
- Nectaplum: a hybrid of a nectarine and a plum.
- Cherum: a hybrid of a cherry and a plum.
- Peacherine and pectarine: hybrids of a peach and a nectarine.
- Nectarcot: a hybrid of a nectarine and an apricot.
These hybrids have had varying degrees of commercial success, and availability may be limited. But development continues, so you may hear of others in the future.More Information: Demystifying Stone Fruit Hybrids -
Selecting Seeds
- While curled up inside the warm, dry house poring through seed catalogs, how do you decide among all the delightful descriptions? First, be clear on the purpose of your garden. Are you trying to grow exotic food? Do you want to attract native butterflies? Are you interested in flowers you can cut and bring inside? Next, think about the conditions of your site. Is it warm and sunny or is there a lot of shade? Do you have heavy clay soil? Choosing seeds that do well in your area makes for healthier plants with less work. At this point, you have the parameters within which to choose what tickles your fancy. If you would like to save seeds in the future, then choose open-pollinated seeds, including heirlooms. Heirlooms are open-pollinated seeds that have been around for multiple generations. Otherwise, you can plant hybrids that have the best traits of their parent plants but will not reproduce true to type from saved seeds. Follow planting directions on the packet for the best results.
More Information: Seed Saving
3. Pests and Diseases
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Identifying Beneficial Insects
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More information: Beneficial Insects
- March, April, May, June, July, August, September -
White Butterflies and Green Caterpillars
- Have you seen these small yellowish-white butterflies fluttering around? Cabbage white butterflies feed on many flowers, but for laying their eggs. They favor the cabbage family, such as broccoli, cauliflower, and mustard. The velvety green caterpillars, also called imported cabbageworms, feed on the leaves after hatching. While mature plants tolerate a few holes munched in their leaves, young seedlings don't have foliage to spare. Cultural controls include handpicking the caterpillars, brushing the eggs off the undersides of leaves, and using row covers to protect the seedlings. UC lists additional options in the link below.
More information: Managing Imported Cabbageworms
- March, April, May, June, July, August, September, October, November -
Fungus Gnats
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For more information: Fungus gnats Management Guide
- May, June, July, Any month -
Kale
- Kale is primarily a cool-season crop in our area but you don’t need to remove it when the weather turns warm. It will grow year-round and even for several years. The problem you are likely to see in the summer is that it gets buggy. If you can tolerate the giant whiteflies and aphids, you can leave it as a decoy plant to attract the pests away from your other plants and to feed the lady beetles so that they will stick around. Kale grows well in the ground or in containers and is not picky about the soil. If the plant gets too big and grows a tall stalk, like walking stick kale, you can cut off the top, remove the lower three or four leaves from the stalk, and stick it back in the ground and water it. It will regrow easily. You could also wait for the seeds and grow again from seed. It will probably be pest-free again and pleasantly edible when the weather turns cooler.More Information: Kale
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Fire Blight
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It is spread by insects, rain, or pruning. The bacteria enter through the blossoms and travel down the tree. If left unchecked, fire blight can enter the trunk and kill the entire tree. Prune infected branches back to healthy wood, at least eight inches below visible damage. If the inside of the branch is discolored, you need to cut back still further. Clean pruning tools between cuts so as not to spread the infection. A less effective way to control fire blight is to spray the open blossoms with a copper spray. Planting varieties that are less prone to fire blight is helpful. Always promptly clean up fallen fruit and leaves.
For more information, see the UC Pest Note on Fire Blight.
- April, May, June -
Ant Control
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On outdoor and sometimes indoor plants, ants protect and care for honeydew-producing insects such as aphids, soft scales, whiteflies, and mealybugs, increasing damage from these pests.
Ants are among the most prevalent pests in households. UC IPM offers steps to follow in an Ant Emergency.
Ant management requires diligent efforts and the combined use of mechanical, cultural, sanitation, and often chemical control methods. It is unrealistic and impractical to attempt to totally eliminate ants from an outdoor area. Focus your management efforts on excluding ants from buildings or valuable plants and eliminating their food and water sources. Reducing outdoor sources of ants near buildings will reduce the likelihood of ants coming indoors.
Ants on Trees and Shrubs
When numerous ants are found on plants, they are probably attracted to the sweet honeydew deposited on the plants by honeydew-producing insects such as aphids or soft scales. Ants may also be attracted up into trees or shrubs by floral nectar or ripening or rotten sweet fruit. These ants can be kept out by banding tree trunks with sticky substances such as Tanglefoot. Trim branches to keep them from touching structures or plants so that ants are forced to try to climb up the trunk to reach the foliage.
When using Tanglefoot on young or sensitive trees, protect them from possible injury by wrapping the trunk with a collar of heavy paper, duct tape, or fabric tree wrap and coating this with the sticky material. Check the coating every one or two weeks and stir it with a stick to prevent the material from getting clogged with debris and dead ants, which will allow ants to cross. Ant stakes with bait can also be used around trees.For more information about what ant baits and insecticides to use, please consult the UC Pest Note on Ants.
- June, July, August, Any month -
Brown Marmorated Stink Bug
- Native to Eastern Asia, this pest was introduced to the United States in the 1990s and has been established in Santa Clara County. Some features to distinguish these bugs from other stink bugs are white stripes on the antennae, a blunt head shape, and smooth shoulder margins.
They feed and reproduce on a variety of plants and are particularly damaging to fruit. You can cut cosmetic damage off fruit and still eat the rest of the fruit. To keep out stink bugs, cover vegetable plants with row covers. You can pick the bugs off plants and squish them or knock them off into soapy water. They are attracted to light and can get into homes where if vacuumed up, they can stink up your vacuum bag.
More Information: Brown Marmorated Stick Bug Pest Note -
Whiteflies
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Whiteflies are tiny, sap-sucking insects that may become abundant in vegetable and ornamental plantings, especially during warm weather. They excrete sticky honeydew and cause yellowing or death of leaves. Outbreaks often occur when the natural biological control is disrupted. Management is difficult once populations are high.
- June, July, August, September
Whiteflies use their piercing, needlelike mouthparts to suck sap from phloem, the food-conducting tissues in plant stems and leaves. Large populations can cause leaves to turn yellow, appear dry, or fall off plants. Like aphids, whiteflies excrete a sugary liquid called honeydew, so leaves may be sticky or covered with black sooty mold that grows on honeydew (See UC Pest Note on Sooty Mold). The honeydew attracts ants, which interfere with the activities of natural enemies that may control whiteflies and other pests.
Management of heavy whitefly infestations is difficult. The best strategy is to prevent problems from developing in your garden or landscape. In many situations, natural enemies will provide adequate control of whiteflies; outbreaks often occur when natural enemies are disrupted by insecticide applications, dusty conditions, or interference by ants. Avoid or remove plants that repeatedly host high populations of whiteflies.
In gardens, whitefly populations in the early stages of population development can be held down by a vigilant program of removing infested leaves or hosing down with water sprays. Reflective mulches can repel whiteflies from vegetable gardens, and yellow sticky traps can be used to monitor or, at high levels, reduce whitefly numbers. If you choose to use insecticides, insecticidal soaps or oils such as neem oil may reduce but not eliminate populations. Systemic insecticides may be more effective but can have negative impacts on beneficial insects and pollinators.
For more information see UC Pest Note on Whiteflies. -
Cottony Cushion Scale
- Scale insects populate the stems or branches of plants and suck out the nutrients. Some are soft and some are armored during part of the life cycle. Cottony cushion scale is a soft variety that is often seen on apple trees. The crawlers are reddish and the females develop elongated white egg sacs on their backs, but it is most likely the molting skins that look like cotton that will alert you to their presence. Small infestations can sometimes be wiped off with gloved fingers. Natural predators may also move in to take care of the problem. There are beetles and parasitic flies that can provide good control. Keeping ants out of the tree will also help because ants will protect the pests in order to be able to eat their sugary exudate.
More information: Cottony Cushion Scale Pest Note
- June, July, August -
Tomato Russet Mite
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Tomato russet mites deplete juice from the cells of leaves, stems and fruit. They usually start at the base of the plant and move upward. If not controlled, these pests can kill plants. At first sign of damage, treat with sulfur dust or a spray solution of wettable sulfur and spreader-sticker. More information is found in the UC Pest Note on Tomato Russet Mite.
- June, July, August -
Sudden Oak Death
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Sudden oak death is a disease of oak trees caused by an invasive plant pathogen, Phytophthora ramorum. It occurs in Santa Clara County as shown on this map. If your oak tree went from healthy (green) to dead (brown) with a full complement of dead lives on the tree, it might have died from sudden oak death. More details about what to do are available at UC Pest Note on Sudden Oak Death.
- June -
Codling Moth
- If you grow apple or pear trees, you may have noticed small holes in the maturing fruit and then discovered a worm inside. "Worms" in your apples are actually the larval form of the codling moth. Codling moth larvae can cause a great deal of damage to apples, pears, plums, and walnuts by penetrating the fruit and boring into the core.
Trees should be monitored every week for signs of infestation. Infested fruit should be removed and discarded to break the codling moth life cycle. Sanitation is an important non-chemical step in controlling this pest. Make sure to pick up fallen fruit promptly, and pick apples with holes that are still on the tree. This will keep future populations down.
Pheromone traps can be hung in isolated trees. But if you have just one apple tree don't bother. You will just attract codling moths to your tree.
Fruit can be bagged for protection, but this method is very labor-intensive. Heavy infestations may require the use of pesticides, but proper timing of sprays is critical. Read the UC Codling Moth Pest Note for more information.
- May, June, July, August -
Rose Care
- Roses are notoriously susceptible to many diseases, including rust, black spot, and powdery mildew. For this reason, they are often planted at the edges of vineyards to give an early warning about diseases that can affect the vines. Yet not everything that negatively impacts roses is a disease or pest, so don’t automatically reach for the chemicals. Abiotic disorders are caused by nonliving factors and can be addressed with cultural changes. Blackened areas on canes can be from sunburn. Brown-edged leaves may signal a high concentration of salt in the soil. Yellow leaves may be due to nutrient deficiencies. Deformed growth may be due to exposure to glyphosate, the active ingredient in Roundup. Good air circulation allows the morning dew to dry, and helps prevent rust and powdery mildew. Some practices to keep your roses healthy are to choose hardy varieties, enrich the soil with compost, fertilize regularly but not too much, irrigate directly to the root zone, and remove suckers (the rapid-growing, long canes) from roses. Prune them below the bud union.
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Armored Scale Control
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These parasites suck the living sap from shrubs and trees. Armored scale insects are in the crawler stage in early summer (June). Armored scale has a hard stage that is very resistant to sprays. Control them during the crawler stage when they are soft and vulnerable. Spray with a horticultural (not dormant) oil, once a month for three months. See the UC Pest Note on Scales for important information about spraying.
- June, Any month -
Carpenter Bees
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Female carpenter bees are large, black and shiny. Male carpenter bees are similar in appearance to bumble bees. Both are about an inch long. Males do not sting and females sting only rarely. Carpenter bees are considered beneficial insects because they pollinate many plants and trees. For their nests, they tunnel into unpainted softwoods such as pine, fir and redwood in house or garden structures. Adults over winter in the nests, emerge in the spring, mate, deposit food in the tunnels and lay eggs. The tunnels are sealed with wood pulp and the new adults chew their way out. After the bees emerge, fill the holes with steel wool and wood filler. Apply paint to the surface to prevent re-entry. Further information is available in the UC Pest Note on Carpenter Bees.
- May, June -
Eugenia Psyllid
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This psyllid has been a real problem in California. New leaves on the infected Eugenia look very much like peach leaf curl. The leaves also may become discolored. Thanks to the diligent work of the entomology researchers in biological insect control at UC Berkeley, a parasitic wasp called Tamarixia was released in Santa Clara County in 1993. The wasp is known to go as far as 45 miles and is found throughout the county. It is essential that no insecticide be used on Eugenia species. The Tamarixia wasp cannot do its job if it's poisoned. For more information see the UC Pest Note on Psyllids.
- May, June -
Tick Information
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Ticks are abundant after mild winters and they can carry dangerous diseases. To learn more about ticks, see the UC Pest Note on Lyme Disease. Be sure to visit the County of Santa Clara website for information about ticks.
- June -
Tomato Hornworm
- Both tomato hornworms and tobacco hornworms can do significant damage to tomato plants. They can eat entire leaves and take bites out of the fruit. Although they are large with a striking appearance, they camouflage themselves well on plants and can be surprisingly hard to find. Once you see one, you’ll wonder how you missed it. The first clue to their presence is often a pile of frass (insect larva excrement) on the leaves or ground under the pest. They are up to four inches long so they are easy to handpick for disposal. If you see a row of white eggs on their backs, those are from a parasitic wasp that will take care of the problem naturally. They are striking, with white striping and little round circles. The caterpillars get their name from the horn on their back end, and they are the larval stages of rather large brown moths.More information: Tomato Hornworms
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Fusarium Wilt
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This is the most prevalent and damaging tomato disease. It also starts with the yellowing of lower leaves, but the yellowing may be only on one side (stopping at midrib) of the leaf or just one branch or one side of the plant. The older leaves will droop and curve downward. The yellow leaves wilt and die, gradually killing the whole plant. Sometimes a single shoot is killed before the rest of the plant shows any damage. More information at UC Pest Note on Fusarium Wilt.
- June, July -
Earwigs
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Earwigs are third only to snails and slugs in causing plant damage. While they are beneficial because they eat insects such as aphids, they also feed on soft plants. Earwigs can do quite a lot of damage if there is a high population. They feed at night and hide in moist, tight-fitting places during the day. Trap them by putting out moistened, tightly rolled newspaper or corrugated cardboard in the evening. In the morning dispose of the paper and the trapped insects. Other control methods are described in the UC Pest Note on Earwigs.
- May, June -
Gophers
- Have you ever watched a plant wiggle and then disappear underground right before your very eyes? That’s the work of a gopher. You don’t often see them because they spend most of their time in underground tunnels, but you see the damage they do by chewing on plant roots or irrigation lines. One way to distinguish them from other soil-dwelling vertebrate pests is by the crescent-shaped mounds of dirt they make when they dive back down. Fresh mounds of moist soil are an indication of recent activity. They do not hibernate, so they are busy year-round. They can be eliminated through trapping and dispatching. Gophinator, Macabee, and Cinch traps specifically designed for gophers are the most commonly used. You can plant trees and shrubs in gopher baskets in the ground to protect their roots. You can also line the bottom of raised beds with hardware cloth to keep the gophers from burrowing up into the beds.
More information: Gopher Pest Note
- June, July, August, Any month -
Spotted Wing Drosophila
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Unfortunately, the Spotted Wing Drosophila is infesting local cherry, berry, and some other fruits. Look for holes in the fruit. Once the eggs hatch, maggots develop and feed inside the fruit, causing the flesh of the fruit to turn brown and soft. Dispose of infested fruit. Information on identification and control can be found in the UC Pest Note on Spotted Wing Drosophila.
- May, June -
Squirrel Control
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For more information: Pest Note on Tree Squirrels and Pest Note on Ground Squirrels.
- May, June, July, August, Any month -
Verticillium Wilt
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Verticillium wilt is a soil-borne fungal disease that damages plant veins. The damage is characterized by affecting one side of the plant. The leaves may wilt and turn brown, dying upward from the base of the branch to the tip. Dead leaves often fall, but may not. Mildly affected plants may survive if fertilized and encouraged into vigorous growth. The fungus can live for years in the soil.
Planting tomatoes, peppers, eggplants, and potatoes (all members of the Solanaceae or nightshade family) in the same place no more than once every three years helps reduce the fungal population to non-harmful levels. Soil solarization may eliminate Verticillium wilt from infected soils. Crop rotation with cereals or broccolis can reduce the pathogen. Avoid high nitrogen fertilizers. Plant Verticillium wilt-resistant varieties of tomatoes, potatoes or strawberries. Refer to the UC Pest Note information on Tomato, Potato, and Strawberry for species-specific suggestions.
- May, June, July, August -
Today’s Grubs Are Tomorrow’s Beetles
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More Information: What are White Grubs?
- April, May, June, July, August, September, October -
Giant Whiteflies
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Giant whiteflies were only discovered in California in 1992, but the infestation is now widespread in the San Francisco Bay Area. Plants most affected are ornamentals, such as begonia, hibiscus, bird of paradise, mulberry, and others. Adults produce spirals of wax primarily on the underside of leaves and lay their eggs in waxy bands which grow heavier as the population increases. Wax filaments grow to lengths of up to 2 inches, but in shielded areas, they can reach ten inches long! Even though affected plants weaken, they rarely die. Manage giant whiteflies by removing infected leaves, washing the undersides of leaves with strong streams of water, and encouraging beneficial insects to control populations.
More Information: Giant Whiteflies in Your Garden
- June, July, August, September