Ornamentals

Aloe Plants

Clockwise from upper left: Aloe striata (coral aloe), Aloe juvenna (Tiger Tooth Aloe), Aloe polyphylla (spiral aloe), Aloe ‘Delta Lights’

The Aloe genus contains hundreds of different species, with Aloe vera being the most commonly known because of its medicinal uses. They are all succulents, and the majority have spines along the leaf edges. Their dramatic stalks of flowers are often visited by hummingbirds. Most species flower yearly; however, some types bloom more frequently, even year-round. The plants need little care, but because they come in all sizes, make sure you know how big a particular species will grow before you plant it. UC Davis has a Botanical Notes publication that includes notes about some of their favorites.

You can see their dramatic stalks of flowers here. Photo: Aloe flowers, clockwise from upper left: Aloe ferox, Aloe striata (coral aloe), Aloe polyphylla (spiral aloe), Aloe ‘Rooikappie’

Amaryllis or is it Hippeastrum?

Brighten the holidays with Amaryllis (Photo: UC Solano Master Gardeners)

The showy red Amaryllis (more correctly called Hippeastrum) is a great bulb for growing indoors if you can’t wait for your outdoor bulbs to bloom in spring. Choose a pot just slightly larger than the bulb. Plant it in loose potting soil with a third of the bulb sticking up above the soil surface. Keep moist, but not so wet as to rot the bulb. The University of Minnesota Extension has information on general care and how to control blooming.

Arboretum All-Stars

Clockwise from top left: pineapple guava, compact Oregon grape, Christmas cheer poker plant, Cooper’s ice plant, UC Davis Arboretum

UC Davis, known for its horticulture expertise, has its own roster of 100 top-performing plants to consider for your garden. To make the cut, each Arboretum All-Star must be attractive for most of the year, thrive in California’s Mediterranean climate, and be thoroughly tested at the UC Davis Arboretum. To see them in person, take a day trip to the Arboretum – it’s open and free to the public. Or access their searchable database and find the perfect All-Stars for your specific garden conditions, along with planting plans and where to buy them.

More Information: UC Davis Arboretum All-Stars

Attracting Bees

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.

Bamboo

Bamboo escaping under a wall, by Laura Monczynski

Bamboo has a reputation for spreading out of control, but not all varieties are classified as running bamboo. There are clumping bamboos that are easier to contain. Bamboo is grass, albeit one that can grow over fifty feet tall. Tall bamboo is often used as a privacy screen. It does best in full sun or partial shade. It is fairly drought tolerant and is an easy plant to grow. Deep barriers may be able to keep it from spreading. If planting in a container, check regularly to make sure the roots are not escaping from the drainage holes and thus growing beyond the pots into your yard or your neighbor’s. Foothill College in Los Altos Hills has a bamboo garden with over 80 varieties of bamboo if you’d like to see how many different ways bamboo can grow.

More information: Growing bamboo

Bare Root Plants

Bare-root tree planting, by Chuck Ingels, UC

Bare root plants are sold without any soil clinging to the roots making them easier and less expensive to transport; they'll do just fine in the garden as long as you don't let them dry out before planting. Because you can see the roots and can control how they're placed in the soil, it helps reduce the chances of root girdling problems later. Buy and plant early in the month while roots are still fresh.

The bare roots should be soaked from an hour to overnight (large plants) in a bucket of water before planting. Trim roots of broken, dead, or spongy bits and carefully pull the roots apart. Dig a hole that is fairly shallow and wide. Spread the roots out sideways and have the crown of the plant several inches above the soil level. This is necessary as the plant will settle down over time. Water in well but wait to fertilize until you see new shoots growing. Be sure to water regularly if the rains are sparse. Staking may not be necessary.

Trees aren't the only plants that are sold bare root. You can also plant bare-root asparagus, artichokes, rhubarb, berries, kiwifruit, horseradish, rhubarb, grapes, roses, strawberries, and iris in January.

More information: Planting Bare-Root Fruit Trees

Bare Root Roses

January and February are ideal for planting bare root roses. When you choose roses, the American Rose Society can help you navigate the 150 species and thousands of hybrids. Besides color and growth form, you may also consider the balance between scent and appearance. Many of the older roses are highly fragrant, while many newer roses are bred for beauty and large blooms. Consider the susceptibility of roses to many diseases when choosing a spot in your garden. They do best with six hours of sun, in well-drained soil, with good air circulation, and without overhead watering. When planting, mix organic material with native soil in the planting hole. Make sure the base of the plant remains an inch or two above the surrounding soil so that water doesn’t accumulate around the crown. Water thoroughly immediately after planting.

More Information: Selecting and Planting Bare Root Roses

Bone Meal for Bulbs?

Bone meal has traditionally been used as a phosphorus source for flower bulbs, but you may want to reconsider. If your soil is healthy, you may not need it and you may be better off with a balanced fertilizer designed for bulbs or even nothing at all. The nutrient content of commercial bone meal is lower than in the past due to the cleaning process, and the bone smell may attract raccoons or dogs to dig up the bulbs.

California Natives

Master Gardeners’ Berger Native Demonstration Garden, by Rebecca Schoenenberger

Thinking of adding native California plants to your yard? New natives respond best to wet winter weather, which promotes the extensive root development needed for spring growth and the hot dry summer months ahead. Your next question may be what to plant. That depends on your planting site and the individual cultural requirements of the plant. To help, the California Native Plant Society has created a database where you can enter your address and find which plants do best in your neighborhood for the conditions in your yard, like sun or shade. The website even lists nurseries that carry California natives.

More Information:

California Poppies

The California poppy, seen on hillsides in late winter through early spring, can be grown in your own yard.

It can re-grow from a taproot or reseed itself rapidly throughout your garden and lawn, so consider whether this would be acceptable. If it is, seeds can be scattered now or with initial rains for vibrant color in a couple of months.

Camellia Petal Blight

Camellias are beautiful except when the flowers turn a blotchy brown. This petal blight is caused by a fungus that continues to live in the soil once a plant is infected. To reduce outbreaks, pick off all infected flowers and dispose of them in green waste. Home composting is not hot enough to destroy the pathogen. After blooming, pick up any petal debris. Then spread fresh mulch around and beyond the bush (but keep the mulch a few inches away from the trunk).

More information: Camellias Petal Blight

Camellias

Camellia japonica ´Professor Charles S. Sargent’, by Barbara H. Smith, Clemson Extension

Camellias can be planted in fall through spring. Since they bloom in winter, choosing a plant now will ensure that you know the color, shape, and size of the flowers with which you will live for many years. Camellias are not native to our area so may need some extra attention in order to grow successfully. Our native clay soil does not drain well so it must be amended for camellias. Our alkaline soil needs to be acidified, and sulfur pellets are one way to achieve this. The plants need some shade and need to be kept moist. Mulch helps hold in moisture, and pine needles, redwood bark, and coffee grounds are all good organic materials that will break down over time and help improve the soil. Pick up flowers as soon as they fall to the ground to avoid the spreading of a disease called Camellia petal blight.

More information: Camellia Pests

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

Creating a Pollinator Garden

Pollination is the process of transferring pollen from the anthers of a flower to the stigma. It is a requirement for the production of fruits and seeds. In addition to wind and water, pollinators include bees, hummingbirds, butterflies, moths, bats, flies, and beetles.

You can support the pollination process—and help counter habitat destruction—by selecting plants attractive to common pollinators. UC has many resources for planning a pollinator garden. Here are a few to get you started!

How to Attract and Maintain Pollinators in Your Garden, UC ANR Publication 8498
Creating a Pollinator Garden, UC Master Gardener Program Statewide Blog
Encouraging Native Bees & Other Pollinators, California Garden Web

Deadheading

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.

Decay in Trees

Shelf-like fungus or mushrooms growing on trees indicates advanced internal decay. Once these external fruiting structures appear, the infection is likely widespread inside the tree. To reduce the chance of infection, protect trees from injury, provide adequate water and fertilization, and prune trees correctly when young to avoid significant pruning cuts when they’re older. Regularly inspect trees and consult an arborist if you spot fungal growths or other signs of decay. The arborist can assess the extent of rot and the structural integrity and make recommendations. More information: Wood Decay Fungi in Landscape Trees

Don't Plant an Invasive Plant

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.

Dormant Rose Pruning

Rose 'Pink Pillar'

Winter is the best time to prune roses even if they haven’t gone completely dormant. The old advice was to cut the canes down drastically, but that isn’t necessary for our climate. Instead, just cut back about one-third to one-half of the total height. In other words, take a 4-foot bush down to about 2–3 feet. When cutting back a cane, make the cut at an angle just above an outward pointing bud. Take out any dead or diseased canes, remove suckers below the graft union, and branches that are crossing or growing towards the middle of the plant to improve airflow. Clean up old leaves on the plant and ground to reduce rust and black spot.

More Information: Rose Care

Drought Tip - No Fertilizer

Fertilizing your lawn and landscape encourages lush new growth. That’s usually what we want, but not during a drought. That new growth requires extra water to support it. Plus, if a plant is already drought-stressed, fertilizer may cause it more stress by stimulating growth that can’t be supported with limited water. In other cases, plants may slow or shut down growth under drought stress to conserve resources and will not use fertilizer.

More information: Skip fertilizing

Easter Lilies

Beautiful white Easter lilies are normally everywhere this time of year – in nurseries, on Easter dinner tables, and in churches. How do they all come into bloom every year just in time for the moveable Easter holiday? The blooms are forced in commercial growing operations with greenhouses carefully controlled for temperature, light, and moisture. 95% of the bulbs are started in ten farms along the California-Oregon border. The plants are native to Taiwan and Japan and were first described in a Japanese gardening book in 1681. You can plant them outdoors after Easter in moist, well-drained soil with partial sun. Their natural cycle will lead to blooms closer to June in subsequent years. Just don’t let your cats eat them!

More Information: Easter Lily diseases

Echeveria

It's easy to have color in your yard without using a lot of water. Instead of planting thirsty annuals, consider some of the many types of succulents. Echeveria does well in containers or in the ground. Plant them in well-drained soil and allow the soil to dry between waterings. They aren't particular about sun or shade, although some can be a little sensitive to full afternoon summer sun.

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

Extending the life of cut flowers

Use lemon-lime soda or lemon juice to extend the life of cut flowers. The following mixtures supply food for the flowers and enough acidity to deter microbial activity.

Lemon-lime soda mixture. Mix 1 part regular lemon-lime soda (not diet soda) with
3 parts warm water. Add 1⁄4 teaspoon of household bleach per quart of this solution.
Lemon juice mixture. Mix 2 tablespoons of lemon juice (fresh or bottled), 1 tablespoon of sugar, and 1⁄4 teaspoon of bleach per quart of warm water.

For more information, refer to Extending the Freshness of Cut Flowers at Home.

Fall Garden Cleanup

Natural leaf decomposition

It’s an excellent idea to keep the garden clean at all times and to remove dead or dying plants or diseased material. Yet there may be bigger seasonal cleanups when taking out plants that have finished producing or that need to be removed to make room for new plants. Trim woody or overgrown perennials. Remove plant debris that allows insects and diseases to overwinter and then reproduce. Always pick up fruit promptly from the ground to not invite critters or allow diseases to proliferate. It's best to leave fallen leaves in place unless they are diseased. They provide a mulch layer while slowly breaking down and returning nutrients to the soil and then back to the plants. Particularly during a drought, having the soil covered is important for moisture retention. If the leaves are diseased, they need to be removed and put out with the yard waste. Monitor the health of your plants while you're out cleaning up.

More Information: Fall Garden and Landscape Checklist

Fertilizing Ornamentals During Drought

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.

Firescaping

Photo: Water-retaining Opuntia, prickly pear cactus, by Laura Monczynski

After a dry winter, we must be careful about the fire season. Choosing plants carefully and maintaining them well can help to reduce the risk, especially for homes closer to the hills or actually in the hills. Two relevant landscaping principles are fuel reduction and fire path interruption. With fuel reduction, choosing succulents or other water retaining plants will slow a fire down. On the other hand, plants that are dry or have high oil content, such as eucalyptus, juniper, and pine, give the fire fuel to burn hotter and faster. Interrupting the fire path involves spacing plants to avoid a line along which a fire can easily travel. Minimize plantings close to the house. East Bay Municipal Utility District offers a free firescaping booklet that you can download from their website.

More Information: Firescaping Zones

Flowering Vines

Vines are plants that climb or sprawl and can easily outgrow their spaces if not pruned annually or more often. Many are pruned in the winter when they are dormant. This reduces shock to the plant and allows you to better see the structure when pruning. If the vines are flowering, wait until after the blooms have finished. Some vines get cut back almost to the ground to renew them. Some are cut back to the beginning of the herbaceous growth, leaving the woody vines. Others are pruned simply for shape or size. The UC Davis Arboretum All-Stars brochure includes several flowering vines. All-Stars are plants that have been tested and proven to thrive in California. The brochure lists pruning needs. It also has photos, characteristics, and requirements of the plants if you are looking for new plants.

More Information: Marin Master Gardeners: Vines

Flowers To Attract Beneficial Insects

Certain flowers help attract natural enemies of pest insects in the garden. Tiny wasps that parasitize certain insect pests or their eggs need pollen and nectar to survive. Predatory insects (syrphid fly larvae, lady beetles, lace wings, and many others) and mites survive on pollen and nectar from flowers when pest populations are low, and some feed on pollen in order to reproduce.

Most of these beneficial insects are small, and so the best flowering plants to include in the garden are those that have small flowers that have pollen and nectar easily accessible and that bloom throughout the season. Avoid flowers that are difficult to weed out when they reseed.

Many flowers that attract beneficial insects are easy to start from seed and this month is a good time to start them – some indoors any time or outdoors later in the month after frost danger has passed. Examples include sunflowers (try dwarf varieties like ‘Sunspot’ for smaller spaces), calendula, cosmos and many herbs like dill, basil and borage.

Other flowers and herbs that attract beneficial insects are easier to buy as plants. A few examples that can be planted this month are coreopsis, asters, and thyme.

Reference info:
UC Pest Note on Biological Control and Natural Enemies of Invertebrates
UCCE notes on Attracting Beneficial Insects to Your Garden.

Fresh Cut Flowers from Your Garden

We have a webpage to help you choose and grow beautiful cut flowers for your home or to give away. The Cut Flower Planting Chart lists ornamentals we’ve grown successfully. We selected these for their hardiness, appeal to pollinators, and production of good cutting flowers. The chart tells you when to start these flowers from seeds or when to transplant, plus when you can expect to see blossoms.

More information: Tips on planting a cut flower garden

Geranium Care

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.

Going Native

Native shrubs, trees, and flowers are well-adapted to our climate and soil, and support native butterflies and bees and other wildlife. They are drought-tolerant once they are established, but need adequate water for the first year or two to establish a strong root system that will help nourish the plant for years to come. Planting them in the fall gives them time to settle in before being hit by the heat of the summer sun. Consult Water Wise Plants and the California Native Plant Society for more information.

Gray Mold (Botrytis)

Botrytis is gray or brownish fuzzy mold that can attack a wide variety of plants. It likes flower petals, ripening fruits and vegetables, as well as leaves and stems. The spores are spread through the air. It is most severe when there's high humidity and may start forming on decaying matter. According to the UC Pest Note on Botrytis Blight, it is important to remove debris and prunings from the ground. You may even have to pick up flowers daily. Avoid overhead watering.

UC also has information about Gray Mold on Strawberries.

How to Attract and Maintain Pollinators in Your Garden

UC ANR has a publication titled "How to Attract and Maintain Pollinators in Your Garden" that discusses the benefits of providing flowers for pollinators and has a list of pollinator plants that are successful in most California gardens.

Irrigate in Circles and Spirals

Place dripline in a circle or spiral around plants and trees, California Urban Forests Council

When you add a new plant to your landscape, it’s important to keep the root ball well watered until the roots start extending into the surrounding soil. The root ball can dry out even when the surrounding soil is moist, so an irrigation emitter is often placed right at the base of the plant. However, the irrigation needs to change as the plant matures. As the plant grows, move the irrigation away from the base and instead start irrigating in circles or spirals around it. For trees and large shrubs, continue expanding the irrigation spiral as they grow.

For more information: Help Your Trees Survive the Drought

Keep Foliage after Bloom Fade

To keep bulbs/corms/rhizomes/tubers blooming each year, leave the plant’s foliage in the ground long after the blossoms have withered. That’s because the foliage needs to photosynthesize to store energy in the bulb for next year’s blooms. Deadhead the spent flowers by cutting the stalks from the finished blooms all the way back to the base, Then wait for the foliage to die back and turn yellow before removing it. Some people tie the leaves together to tidy the garden, but that’s not advised because it limits the light needed for photosynthesis. As an alternative, intersperse annuals to hide the foliage until it can be removed.

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

Mulch to Conserve Water

Arborist wood chip mulch at our Martial Cottle Park garden

A 3 to 4" layer of mulch can reduce watering needs by as much as 50 percent. Mulch reduces water evaporation and keeps soil temperatures down during hot summer months. In addition, mulch reduces the number of weeds, makes it easier to control weeds that do grow, and protects the soil from compaction. A variety of mulches are available. Organic mulches such as arborist chips and bark nuggets break down and improve soil quality over time. You can find free wood chip mulch from local arborists by searching online, such as “free wood chips near me”. Place mulch away from the street curb to prevent heavy rains from washing it into storm drains. Also keep mulch away from the trunks of woody trees or shrubs to avoid decay problems.

More information: Mulching with Organic Materials

Native Wildflowers

Wildflowers at Martial Cottle Park, by Hank Morales

Native California wildflowers herald the beginning of spring — and the time to plant them is ahead of the winter rain. Besides their showy display, they’re a habitat for local pollinators and a great way to cover up bare spots. If that’s not enough, they also require little care. Just select a well-drained and sunny site, remove weeds, and lightly rake the surface of the soil. Hand disperse seeds and lightly cover with soil, no more than about ¼ inch. Gently tamp them down with the back of a rake and water. After that, let Mother Nature take its course — we hope with some rain!

More information: Native Wildflowers

Neem Oil

Neem products are derived from the neem tree, Azadirachta indica. But most neem products on the market lack the active insecticidal ingredient azadirachtin. Neem oil, called “clarified hydrophobic extract of neem”, is still effective as horticultural oil for smothering juvenile insects and may be effective in suppressing powdery mildew. But it won’t be effective in cases where azadirachtin is required. Like any horticultural oil, neem oil can potentially damage plants by burning their foliage and should be sprayed at dawn or dusk to protect bees and other pollinators. When using any pesticide, it’s important to reach an accurate diagnosis first and understand that no product helps solve every plant problem. Neem is not a cure-all.

More information: More about Neem

Oleander

These plants are obviously not terribly picky about conditions if they live and thrive in freeway medians. Oleander is drought tolerant once established. They rarely, if ever, need to be fertilized in our local soils or sprayed or pruned. But if you want to prune them to fit into a small yard space or to make them look like a tree rather than a bush, you can do so now. As with all pruning, first cut out any dead or dying branches. Then cut any that are deformed or growing in an undesirable direction. After that, you can prune for size and shape. Cut the plant back to a little smaller than the size you ultimately want, keeping in mind that it will re-grow. Take care not to prune off more than one-third of the plant at a time. Make cuts above nodes that face out in the direction in which you want new growth to go. All parts of the plant are poisonous so do not eat it, burn it, or work on it without gloves. The good news is that this latter quality makes it deer resistant.

More Information: Oleander article, Tulare/Kings County Master Gardeners

Perennials and Bunch Grasses

Winter is a good time to cut back perennials and bunch grasses. You can cut back some perennials all the way to the ground. These include yarrow, hummingbird sage, goldenrod, California aster, and most kinds of California fuchsia. You can divide other perennials at this time, such as Douglas iris, alum root, seaside daisy, woodland and beach strawberry, yarrow, yerba buena, daylilies, and chrysanthemums.

You can propagate bunch grasses, sedges, and rushes by division this time of year. Examples of bunch grasses are purple needle grass (state grass of California), fescues, blue grama, leafy reed, oat, and deer grass. Some sedges are the meadow, clustered field, and San Diego sedge. Rushes include the common rush and the California gray rush.

Pinching Flowers and Herbs

Zinnias flourish with pinching, North Carolina Cooperative Extension

Pinching your flowers and herbs is a way of pruning them with nothing more than your fingertips. Removing the new tender growth at the end of a stem stimulates branching, encourages more flowers, and keeps your garden blooming longer. Follow a stem tip down to the first or second leaf node (where leaves join the stem) and pinch it off just above that node. Two new stems will grow beneath the pinch, resulting in a bushier plant. Early spring—before flower buds form—is the ideal time to pinch. But not all plants should be pinched. In particular, don’t pinch flowers that produce only one flower per stem.

More Information: Pinching Flowers and Herbs

Plant Native Shrubs and Flowers

Native shrubs like manzanitas, silk tassel bush, and currants come into bloom and provide nourishment for wildlife at the height of winter. These carefree, water-wise shrubs look good throughout the year.

Winter is still a good time to plant native plants. It is not too late to scatter wildflower seeds like California poppy, mountain garland, baby blue eyes, globe or bird's eye gilia, clarkias, lupines and tidy tips. Make sure the seeds have good soil contact by walking or tamping on the seeded areas. Consider planting native bulbs like wild hyacinth, mariposa lily, harvest brodiaea or soap plant in areas that remain dry through the summer, perhaps at the feet of established shrubs.

If you've had California poppies before, they'll start popping up all around as a result of winter rains. If you're interested in brilliant orange spring color, you can still scatter seeds now. When choosing a spot to plant them, keep in mind that they re-seed themselves readily and they can smother nearby small plants.

Planting Bulbs

Freesia flowers

Bulbs that bloom in the spring are planted into the ground in the fall. These include those that are technically corms, rhizomes, tubers, or tuberous roots in addition to true bulbs. Examples are babiana, crocus, daffodils, freesia, hyacinths, iris, ixia, sparaxis, and tulips. They can go into the ground in groups, into pots, or be tucked in amongst other plants. They need to be in a place that doesn’t stay wet because they will rot with too much water. It is important that the soil has good drainage. They flower best in full sun or filtered shade.

Be sure to plant them with the pointy side up because new growth will come from that point. A rule of thumb is to plant them twice as deep as the diameter of the bulb, but follow instructions for the specific flowers. Water them in at planting time.

More Information: Bulb Planting Schedule , Tips for Growing Bulbs

Planting Ornamentals

California Native flowers, by Ola Lundin, UC

Spring is when thoughts turn to planting, yet fall is an excellent time to plant perennials. You can plant many trees, shrubs, and other long-lasting plants in the fall. This applies particularly well to California native plants. Putting them in now will give them a chance to start developing strong root systems with the winter rains before they are stressed by summer heat. Make sure to water new plantings regularly until they have established good root systems and can survive with less supplemental water.

When choosing plants, consider our general Mediterranean climate as well as the microclimate of your yard. Local California natives in particular need little to no amending of the soil because they have evolved in our clay soils. Sun times, water needs, wind exposure, and soil type can all impact the success of a plant. Make sure you know how large the plant will become, even if it looks fine now in a one-gallon or five-gallon container.

More Information: Mediterranean Plant List

Plants to Attract Butterflies

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.

Poinsettias

Poinsettias are tropical plants, so they'll do best in a warm, sunny place in your house. The soil can easily dry out and become hydrophobic, so make sure to check the soil moisture regularly. There’s really no need to fuss over them if you’re only keeping them for a few weeks of holiday color. If you want them to bloom again next year in time for the holidays, UC has Poinsettia Care Tips that describe what to do; just be aware that it is a little tricky.

Did you know that the red parts are actually bracts (modified leaves) and that the true flowers are the little yellow parts in the centers? You can also plant them outdoors with protection from frost. They have been seen growing as tall as eight feet in San Jose, and taller in their native Mexico.

Poisonous Plants List

As we approach the holidays, there are a lot of questions on poisonous plants. Fortunately, many of these plants have a very bitter taste that limits the amount of the plant eaten.

Poinsettia and mistletoe should be kept away from curious children, but the list includes other flowers and plants such as azaleas, calla lily, carnation, daffodil, foxglove, hydrangeas, iris, lantana, narcissus, poppy, sweet pea and tulips.

Different parts of the plant may be toxic. Consult the UC Poison Plant web page for detailed information.

Potting Mix vs Planting Mix

Is there a difference between potting mix, potting soil, and planting mix? The best advice is to read the label. The terms for bagged mixes aren’t regulated, so they can vary by manufacturer. What’s important to know is that not all bagged mixes can be used in pots. Some are meant to be used as garden fill, amendment, or mulch, so they won’t provide the right water retention, drainage, or nutrients for container gardening.

For more information: Bagged Potting Mixes

Pruning Azaleas and Rhododendrons

Azaleas and rhododendrons can be pruned as soon as they finish flowering. This is also a good time to fertilize them. Choose an acid-forming fertilizer blended for these particular plants, and be sure to follow the label directions for amounts. Learn more by visiting the Azalea and Rhododendron society websites.

Pruning Bougainvillea

You can prune at any time to shape or direct growth. If it is growing on a wall, cut back long stems to keep producing flowering wood. Hard pruning to renew the plant should be done in the spring after the last frost.

Pruning California Natives

If your landscape includes California native plants, you may wonder if you should prune them. It depends. Some don’t respond well to shaping or shearing to control size. But they do like careful pruning at the proper time, which is when they are dormant. That could be either summer or mid-winter. Natives that do well with winter trimming include California buckeye (Aesculus californica), honeysuckle (Lonicera hispidula), and salvia species. California fuchsia (Epilobium canum) and lilac verbena (Verbena lilacina) can be cut almost to the ground. But wait until summer for grasses and broadleaf evergreen shrubs and trees.

More information: How to Prune California Native Plants

Pruning Camellias

April and May are the best time to prune camellia. Camellia should be pruned just after flowering and before new vegetative growth gets going. If you prune later in the season, you risk damaging next years blossoms.

Pruning Fuchsias

The time to prune fuchsias is early spring, after the chance of frost is past. If there is frost damage prune it out and take off some of last summer's growth. Leave at least two or three healthy leaf buds on each branch. Fuchsias have a tendency to get leggy. Frequently pinch the tips of the branches during the spring and summer to force side growth, making the fuchsia bushier. Pick off flowers as they fade.

More information: UC IPM list of common pests and disorders of fuchsias.

Pruning Hydrangeas

For better-looking hydrangeas, prune out the spent blossoms. Hydrangeas are fast growing and need pruning to control size and shape. Cut out the older stems that have flowered, leaving the ones that have not flowered. For the biggest flower clusters, reduce the number of stems. For lots of medium size flowers, keep more stems.

Root Knot Nematodes

Root knot nematodes usually cause distinctive swellings, called galls, on the roots of affected plants. They can infest a wide variety of plants and easily spread via soil left on tools or shoes. Infested plants may not die but may be sickly or less productive. When you pull out your annual plants, inspect the roots, especially if they didn’t do well. Avoid spreading root knot nematodes by cleaning tools thoroughly. Consider letting an infested bed lie fallow for a season, or plant a cover crop next summer of French marigolds, which help suppress some nematodes.

More information: Nematodes Pest Note

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.

Roses: Diseases and Abiotic Disorders

Seed Viability

Seed packets have a “packed for” date on the back. Yet seeds can still be viable for years beyond that date if stored correctly. Ideal storage conditions are cool and dry. The older the seeds are, the lower the germination rate will be. So plant more of the older seeds than the number of plants you ultimately want. You can do a germination test by putting seeds on a damp paper towel and enclosing them in plastic to keep them uniformly moist. Do this right before planting time so you can transplant the ones that successfully germinate. Or you can take your chances and just plant them directly and see what comes up. If you are saving your own seeds, make sure to choose seeds from the healthiest plants.

Whenever it's hard to find flower seedlings, if you have some old flower seed packets, you can scatter the seeds randomly in a section of your yard and enjoy whatever flowers.

More Information: Vegetable Seed Viability

Selecting Seeds

Illustrated Seed Structure, California Master Gardener Handbook

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

Shovel Pruning

Sometimes a plant just isn’t working out in your garden and it comes time to part ways. The most drastic form of pruning is “shovel pruning” where you finally just dig the plant out. Another term for this technique is “editing the garden.” Perhaps you saw a plant you liked in another part of the country or world. If that other location had a different climate or soil type, it may not translate well to sunny, dry California with our clay soils. Perhaps you want to garden organically but the plant has too many pests or diseases and you are having trouble controlling them with organic methods. Or maybe it simply doesn’t resemble what the tag promised. It’s okay to let go. Spring and Fall are good times for new plantings, so it is also a good time to reassess the appropriateness of what’s in your yard.

Success with Houseplants

If you enjoy houseplants, Ernesto Sandoval, the Director of the UC Davis Botanical Conservatory can help. He has advice about selecting plants that tolerate the light and humidity levels of your home as well as tips about how to care for them. For instance: Overwatering is the number one killer of houseplants. Allow succulents to dry completely between watering. Water leafy plants that recover easily from wilting when they start to droop. For more information, including many useful tips, watch his video presentation: Growing Houseplants

Sweet Peas

You have probably heard people use the "sweet peas" term incorrectly. In garden terminology, sweet peas are flowers. They are not edible and are poisonous. Edible peas, even if sweet in taste, are not correctly called sweet peas. Sweet peas are incredibly fragrant vining flowers that come in a variety of colors, mostly pastels. They are an annual flower so they must be planted again every year. You can sow seeds anytime during the winter for spring bloom. The seeds are hard and it can be helpful to nick them slightly before putting them in the ground. Sweet peas do best in full sun or light shade. The plants will decline when it gets hot outside and they will need to be removed. Remember, you cannot eat sweet peas.

Time to Prune Frost Damage

Frost damage on pelargonium

When there is still a danger of frost, we recommend leaving frost damage on plants so it provides protection to undamaged parts. Once the cold winter weather is behind us, it's time to prune frost-damaged plants. Pruning it off would stimulate tender growth that is susceptible to frost. Although the typical last frost date will vary depending on your location within the county and its microclimate, it’s time to start the spring cleanup soon.

More information: Treating Cold-Damaged Plants

Trees Planted Too Deeply

The root flare should show at the soil line. Left by David Snow, Michigan Extension, right by Sarah Browning, Nebraska Extension

When you plant a tree or shrub, look for the root flare; it’s the point at the base of the trunk where the roots start. The soil should be at that level when you put the plant into the ground (or even into a new pot). Planting too deep can prevent the roots from getting the oxygen they need or cause the bark to deteriorate at ground level. Either can stunt plant growth, resulting in branch dieback or causing bark cracking. Don’t assume a container plant is at the correct level; you may need to remove soil to find the root flare.

More Information: Trees Planted Too Deeply

Tropical Flowers

If you have your heart set on tropical and subtropical plants like bougainvillea and hibiscus, planting in May will give them time to get established before the cold weather hits in the fall. Planting them in a protected area such as under eaves may keep you from having to cover them on cold nights.

USDA Hardiness Zones

Planting zones help you select plants that are right for your garden. There are two systems, USDA and Sunset Western Garden.

USDA divides the US into hardiness zones based on average high and low temperatures. Most of Santa Clara County is in zones 9b and 10a.

Sunset makes many finer distinctions, taking into consideration rainfall patterns, ocean influence, and more. In the Sunset system, Santa Clara County is largely zones 15 or 16 with some zone 7 for areas with more extreme highs and lows. Sunset zone maps: Central and South County and North County.

For gardening success, choose plants known to thrive in your zone.

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)

Winter Irrigation

Depending on the fall weather and rain frequency, you will likely set your sprinklers to water less frequently or even turn them off for a while. It's still important to check outdoor plants to ensure they have enough water. While they need less water when it's cool, it's important to make sure they don't dry out. If you have a lawn and rains haven't come, irrigate the lawn once or twice this month.

If it has been raining, the soil may be saturated, so be careful if you have to walk on it to not compact it. Also, if the soil is waterlogged, vital space for air needed for plants and worms, and excess water can drown beneficial soil organisms and contribute to rotting roots.

Yellowing Leaves on Gardenias

Chlorosis is usually caused by a lack of iron in the soil. With a mild case, the veins remain green and as it becomes more severe will turn completely yellow. Treat the soil with iron chelate according the package directions.

Ornamentals

Ornamentals Tips