We in Northern California are fortunate to live in a climate that enables us to garden all year. Our moderate temperatures enable many vegetables to grow through the winter, and at most lower altitudes, frosts are rarely severe enough to kill resistant plants and vegetables.
Sunlight warms the soil, and retained heat minimizes the effects of below-freezing temperatures. Sunlight warms the plants themselves, and provides the light energy that enables the complex chemical process of photosynthesis.
The problem of sunlight for winter gardeners is that there is simply less of it. Everyone knows this, but too often we don't consider it carefully when planning or planting a winter garden. In summer, one must often think about protecting plants from harsh, direct sunlight.
In winter, plants must be placed where they will be exposed to the maximum light available. In winter, not only are the days shorter by several hours, but the sunlight strikes the earth at an indirect angle, thus transmitting less energy for heat and photosynthesis.
Compared to other seasons, the winter sun rises later, describes a much lower arc through the sky, reaching barely a quarter of the way to the zenith, and sets much earlier. A winter garden, whether a square mile or a square yard, receives only about one-third of the sunlight it gets in mid-summer, and only half of what it gets in mid-fall and mid-spring.
For the same reasons, shadows from obstructions near the garden such as trees and shrubs or buildings and fences, matter more in winter than in other seasons because they are much longer, shading a larger area for more hours of the day.
A plant which basks in full, radiant sunshine during the bright quarter of the year (May, June, and July) may well be in the chilly shade during the dark quarter (November, December, and January).
Finally, to top off this list of light-deprivation horrors,heavy cloud cover, not uncommon from October through March, reduces available sunlight even further, by a factor of over 50 percent.
This “light assessment” will involve a bit of thought and time, and maybe some rudimentary diagramming, but it will pay off in better plant location, much more vigorous plants, and more success in gardening through the winter.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
Cold, windy, rainy weather provides ideal conditions for the development of Citrus blast, a disease that affects many varieties of citrus grown in Butte County, including oranges, grapefruits, lemons and mandarins. Citrus blast is characterized by individual leaves that rapidly wilt, dry up, and die on the tree. The leaf stem turns brown and a brown lesion will form on the twig where the infected leaf is attached. The leaf blades may drop or remain stuck on the tree but the dead leaf stem (petiole) often remains attached to the twig. On young vigorous shoots the lesion at the base of an infected leaf may grow around the shoot, girdling the twig and causing twig dieback. On damaged twigs a reddish-brown crust will form over the diseased spot.
The most effective control of citrus blast is achieved by spraying a protective fixed copper material before the first heavy rain in November. Sprays applied in the fall will help protect leaves and shoots from winter storms, but must be applied before blast injury occurs. In years with heavy rainfall, a second spraying in January is appropriate to protect tissues from storms in February and March. These sprays will also help protect fruit from fungal infections that cause fruit loss. Cultural practices that harden off growth in the fall before the cold, rainy weather arrives will help reduce the severity of blast damage. Avoid over-fertilizing that encourages trees to add tender late-season new growth. The last nitrogen fertilization on citrus should be applied no later than late May. Using these chemical and cultural controls should help reduce blast damage to citrus trees.
Winter has finally arrived in the north state! Winter temperatures can pose a threat to the fruit and foliage of citrus, as well as other succulents, tender perennials, tropical and subtropical plants.
The most common type of frost in California is referred to as radiation frost. Radiation frost occurs on cold nights when the air is clear and still. Soil, buildings, plants, and other objects at the earth's surface act as a heat reservoir by absorbing heat during the day. Heat is lost, or radiated, from the earth's surface into the atmosphere and plants are damaged when enough heat is lost from this reservoir to lower the temperature at the surface to below critical temperatures. Greater damage occurs with colder temperatures or a longer duration of cold. Temperatures can drop more rapidly when the air is very dry and the dewpoint is low. If the dewpoint is very low a freeze can occur without the formation of dew and frost. This condition is known as a “black frost.”.
Avoid planting frost-sensitive trees in the lowest areas of the yard or garden, as cold air tends to flow downhill and can accumulate in such depressions. Trees planted near structures or walls, particularly those with southwest exposure that absorb and retain reflected heat during the day, may be damaged less during periods of frost because that heat is released during the night. Fertilize and prune during the spring and early summer so that new foliage will have enough time to mature before the onset of cold weather. Bare, moist soil stores more heat during the day and radiates more heat during the night, so rake away mulch, ground cover, weeds and leaves from around the tree during cold weather.
Monitor weather forecasts and take note of how low temperatures will go, and for how long. When the weatherman warns of frost, there are several precautions you can take to protect your plants.
- Identify cold spots in your landscape by monitoring with thermometers
- Identify plants at risk: citrus, succulents, tender perennials, tropical & subtropical plants
- Have supplies ready: either sheets or blankets with stakes or a framework to hold covers off foliage, or frost cloth (which can lie directly on plant foliage); lights; wraps for trunks; thermometers.
- Wrap trunks of tender trees, using towels, blankets, rags or pipe insulation.
- Move potted plants to warmer spots next to the house or under a patio cover.
- Water plants and trees. Dry plants are more susceptible to damage and moist soil retains heat better than dry soil.
- Cover plants just before sunset to capture and hold in as much heat as possible. Remove sheets/blankets daily if it's sunny, to allow soil to absorb heat during the day.
- Add heat by hanging a 100-watt lamp designed for outdoors in the interior of the tree, or use a holiday string of outdoor lights (not LED lights, since they don't give off heat).
If the larger branches of a tree or plant sustain frost damage, don't prune away damaged wood or remove the plant too soon. Wait several months in order to assess the extent of the damage and allow time for possible recovery during warm weather. As new foliage begins to grow, frost-killed twigs and branches will be apparent and can be pruned at that time. Postpone heavy pruning until the following year to allow trees to regrow to the point where damaged wood can be clearly determined.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
- Author: Kim Schwind
In these winter months,while taking stock of the past year's gardening successes and planning next year's garden, why not consider adding a moon garden somewhere in your yard? A moon garden incorporates reflective surfaces, light-colored flowers, fragrant plants, and peaceful sounds, all meant to be enjoyed by the light of the moon. It is the perfect garden spot for busy professionals who don't have time during the day to enjoy their gardens.
All moon gardens have a bench or seating of some kind, providing a place to relax and reflect. If space allows, incorporate reflective elements such as a gazing ball, string lights, light- colored rock pathways or hardscape. Wind chimes, a water feature, or garden art that is propelled by the wind (like a whirligig or windsock) brings sound into the moon garden. Reflective paints on garden pots or pavers can also add nighttime interest.
White or light-colored flowers in shades of yellow and light blue are ideal. Good choices include daffodils, bleeding heart, creeping phlox, azalea, yarrow, Shasta daisy, magnolia, and sweet alyssum. Jasmine, evening primrose, angel trumpet (brugmansia) and moonflower all provide fragrance as well as flowers. Most of these are hardy plants that can withstand our hot dry summers. Choosing flowers that bloom at night helps night-roaming pollinators like bats and moths.
You may already have a deciduous tree in your yard that you can build the moon garden around. For year-round interest plant shrubs with interesting form or color, like Harry Lauder's walking stick (which has fantastic gnarled branches and yellow catkins); yellow twig dogwood; or a witch hazel like Arnold Promise (which has beautiful fall foliage and then blooms in late winter with fragrant crinkly yellow blossoms).
Once you have created your romantic, magical garden, don't forget to take some time to enjoy it. Once outside, allow at least ten minutes for your eyes to adjust to the dark. As you gaze on the garden and begin to notice reflections from the moonlight, you will see that the flowers and leaves appear to be floating. Take in the sounds of your water feature or wind chimes. Breathe in the fragrance of the night-blooming flowers. Relax and enjoy.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
If you are planning to put some new plants in the ground now so they will be established when spring comes around, consider planting a hedgerow. In urban and suburban areas, fences or hedges are typically used to define property lines, block unsightly views, provide privacy screening, and create windbreaks. However, hedgerows are becoming a popular alternative for these landscape duties. While a hedge is made up of a single plant species placed in a tightly spaced row, a hedgerow is a broad bed planted with a variety of trees, shrubs and forbs (herbaceous flowering plants).
Urban and suburban landowners can reap these benefits by planting smaller trees and large shrubs to establish mini-hedgerows instead of fences or hedges. A scaled-down hedgerow will still attract pollinators, beneficial insects and birds. Hedgerows can also create corridors between wild spaces, allowing wildlife to more safely move through neighborhoods. As landscape designer Rebecca Lindenmeyr says, “Hedgerows can provide a slice of wild on the outskirts of a landscape design.”
If you decide to create a hedgerow, try to choose plants with a variety of heights. Different types of wildlife are adapted to living at different levels above the ground. Also, generally speaking, wider is better when it comes to hedgerows. The wider the planting area, the more room there is for a greater diversity of plants. The greater the diversity of plants in a hedgerow, the more likely it is that wildlife will find a suitable habitat there. Look for plants that provide food for wildlife. Selecting a variety plants that produce flowers, fruit, nuts, seeds, or nectar at different times of the year increases your chances of providing food for the greatest diversity of wildlife species.
Native plants are a logical choice for use in hedgerows. They are familiar sources of food and shelter for local wildlife species, and are well adapted to the local climate and soils. Large native shrubs that are suitable for residential hedgerows in our area include California redbud, toyon, many species of Ceanothus and manzanita, coffeeberry, desert willow and coyote brush. California bush anemone, Cleveland and white sage and buckwheat are more moderately-sized natives that can also be useful in hedgerows. Smaller native perennials include deer grass, California fuchsia, milkweed and penstemon. An added bonus is that, once established, all of these natives are at least moderately “deer resistant.” It is important to recognize, however, that if they are hungry enough deer will eat virtually anything.
For further information on residential hedgerows:
Hedgerows and Integrated Pest Management
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
