Monthly tips are categorized by: To-Dos, What to Plant, or Pests and Diseases. Scroll through the list to see items in each category.
- Controlling Bermudagrass
Bermudagrass is a warm season grass, going dormant in winter, so that's not the best time of year to fight it. Spraying it in winter won't work because it can't take up the poison since it is not actively growing. But you can install sheet mulching to smother spring/summer growth, or dig out roots if the soil is not too wet. For more information, read the UC Pest Note on Bermudagrass.- January
- Cut Back and Divide Perennials
Winter is a good time to cut back perennials and bunch grasses. Perennials such as hummingbird sage and most kinds of hummingbird fuchsia can be cut back all the way to the ground. Perennials like daylilies and chrysanthemums can be divided during this time.
Bunch grasses such as purple needle grass (official California state grass), Idaho fescue and deer grass, and some perennials like douglas iris, alum root, seaside daisy and yerba buena, can be propagated by division this time of year.- January, February, December
- Dormancy and Chill Hours
The positive side of cold weather is that fruit trees native to colder climates, such as cherries and blueberries, may get the chill hours they need to produce good fruit. Going dormant saves energy which can then go into fruit development. No need to protect them on cold nights. Knowing the native habitat of your plants will guide you in caring for them. Mimicking the success of nature leads to greater success in your own garden.
Learn more about chill hours on the UC Fruit & Nut Information website.- January, February, December
- Frost Dates
The first and last frost dates for Santa Clara County are November 15 and March 15. These are important—but approximate—dates for gardeners to remember.
- First frost date—this is the earliest date you should expect frost to occur. If you have plants that need to be brought in for the winter, or crops you need to pick before frost, this date will be important to you.
- Last frost date—after this date, you wouldn't expect any more frosts. It's generally used as a milestone when planting outdoors, or pruning frost sensitive plants (such as citrus where you don't want to stimulate delicate new growth until danger of frost is past).
For people interested in more data about first and last frost dates, look for your city in Utah State University's list of freeze dates for California (only cities with National Weather Service stations are included).
Also see: Frost—Avoidance and Dealing with Damage- January, February, March, November, December
- Fruit Tree Grafting
When pruning dormant fruit trees, you may want to save cuttings (scions) for later grafting onto other fruit trees. Grafting is a technique that allows you to have multiple varieties of compatible fruit on one tree and is a great space saver. Fruit trees can have new varieties grafted to them when they are dormant in January and February.
Scions are available in January at the California Rare Fruit Growers (CRFG) scion exchange. Their January event also includes training classes. Check the CRFG - Santa Clara blog for the date.
More information on grafting can be found at:
- Garden Tools
When you use garden tools be sure to clean them before you put them away especially if you are cutting diseased plant materials. Cooler and wetter conditions make it even more important to wipe mud and sap off metal surfaces before storing them. Our Tool Care Tips provide more information.- January, April, July, October
- Prune Apple Trees
Once your apple tree loses its leaves, it's time to think about pruning. Apple trees produce fruit terminally on spurs located on wood 2 yrs. to 8 yrs. old. Weak and unproductive branches should be thinned out to allow the sunlight into the tree for good spur development. Older spurs can be rejuvenated by cutting back, especially following a light crop year. Tree height is maintained by cutting back upper branches to shorter laterals. Excessive pruning of a bearing tree can negatively affect its vigor and fruit. Consult our Fruit Tree Pruning page for more information.- January, February, December
- Recycle Holiday Plants
If you have a Christmas tree to recycle, please follow the procedure for your local community program so that the trees can be recycled into compost or materials. Insects and diseases which may be on the cut trees could escape and spread if the trees were used as mulch in homeowners' yards.
Other popular holiday plants such as poinsettias, azaleas, or cyclamen can also be recycled. Remove the foil wrapping off the containers (for better drainage) and put the outdoor plants somewhere sheltered until you can plant them. The heated air in your home will dry out both these outdoor plants as well as your indoor plants. You may want to check those indoor plants too.- January
- Save the Worms
Worms aerate the soil with their tunneling, break down organic material such as fallen leaves and make the nutrients available to plants, and they excrete nice rich fertilizer in the process. They help create a sustainable system in your garden and do a lot of your garden chores for you. If you see them on the sidewalk during heavy rains, rescue them and take them to a safe place in your yard.- January, February
- Stake Your Brassicas
Your Brussels sprouts and other brassicas may collapse with the weight of the rain. Tying them to a three-foot stake will maximize your chances for a better crop. If you're noticing yellow flowers on your broccoli already, the cold-then-warm temperatures have caused them to bolt; you can try new plants or start thinking ahead to your warm weather garden.- January
- Winter Fruit Tree Pruning
Pruning Tools – Keep them clean and sharp
Remember to keep your pruners and loppers sharp. Good pruners use bypass blades rather than anvil type. Anvils have only one cutting blade and one flat blade which can result in "smashing" the plant material. Sterilize the pruners or loppers between each plant and after cutting off any diseased plant material. Use a 10% bleach solution (1 part bleach, 9 parts water) or disinfectant bathroom cleaner.
What and When to prune
According to UC's Backyard Orchard website, "the optimum time of year to prune fruit trees is the dormant season, December, January (best) and until the middle of February." Apricots are the exception for pruning in January; they should be pruned in the summer after harvest. If you properly prune and care for fruit trees you will get the highest yield of fruit. A good rule of thumb is to prune plum, pluot, apple, and pear trees 15-20%; and peaches 50%.
January is also a good time to prune roses. A basic guide is to keep 3-6 strong, healthy, outside canes per plant and leave 3-5 buds on each cane. Cut on the diagonal ¼ inch above an outward-facing bud. More information is available at UC Pest Note on Roses: Cultural Practices. The San Jose Heritage Rose Garden offers free hands-on pruning classes every Saturday in January and February.
Deciduous trees can be pruned anytime during their dormant season (in winter). Prune deciduous species, such as Western spice bush, creek dogwood, Western mock orange, red-bud, maples and deciduous oaks.
Do not prune apricot and cherry trees in winter because they are susceptible to Eutypa dieback. The best time to prune them is late August before the rainy season starts.
While you're outside pruning, remember to pick up any rotting fruit on the ground at the same time.
Make your cuts with care in order to direct the growth for next year. To have an open tree with good air circulation, make cuts above outward-facing nodes. Choose nodes where you want new growth and make a cut about a quarter inch above, refer to the image below.
- January, February, December
Also refer to our page on fruit tree pruning page.
- 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 make sure 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 so as not to compact it. Also if soil is waterlogged, vital space for air that is needed for plants and worms and excess water can drown beneficial soil organisms and contributed to rotting roots.- January, February, December
2. What to plant
- Amaryllis or is it Hippeastrum?
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. blooming.
- January, December
Photos: UC Solano Master Gardeners, Growing Amaryllis or is it Hippeastrum?")
- Bare Root Plants
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 for 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.- January, February, December
- Plant Asparagus Crowns
Asparagus crowns can be planted now. Dig a trench eight to twelve inches deep, mix in fertilizer at the bottom and cover with two inches of soil. Set the roots in the trench about 18 inches apart, and cover with two inches of soil. Gradually fill in the trench as the plants start to grow. Asparagus is a perennial vegetable that will produce for several years. It's best to wait until the second year to harvest to let a strong root system develop for long term production. For more information, read UC Davis' Growing Asparagus in the Garden.- January, February, March
- Plant Bare Root Roses
Roses are available as bare root plants from late fall through early spring. Packaged and mail order plants may have their canes covered with wax. This helps prevent drying while shipped or kept in retail stores. Don’t worry about the wax as it will degrade and break away from the canes after growth starts. January is a good time to plant bare root roses. For more information see UCCE Instructions on Selecting and Planting Bare Root Roses.- January
- Plant Cool Season Vegetable Seeds for Transplanting
Plant seeds for cabbage, chard, broccoli, cauliflower, and spring lettuce in a cold frame or in the greenhouse. Consult our Vegetable Planting Chart for when to transplant your vegetables.- January
- 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.- January
3. Pests and Diseases
- Control Insect Pests with Horticultural Oil
Spray apple, pear, peach and nectarine, apricot trees with horticultural oil during the dormant period to control scale, and aphid and mite eggs. For more information on using horticultural oil to control pests consult:
- UC Pest Note on Scales
- UC Pest Note on Aphids
- UC Pest Note on Spider Mites
- Peach Leaf Curl Preventive Care
If you had a serious problem this past year with peach leaf curl, where the leaves became red and distorted, spray the tree with a fungicide once all the leaves have fallen (late November, early December).
Generally a single early treatment when the tree is dormant is effective, although in areas of high rainfall or during a particularly wet winter, it might be advisable to apply a second spray late in the dormant season, preferably as flower buds begin to swell but before green leaf tips are first visible.
Use a fixed copper spray, as detailed in UC Pest Note on Peach Leaf Curl- January, November, December