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.
There are several advantages to planting bare-root trees: they are usually less expensive, easier for gardeners to transport, and they will grow their roots entirely into native soil (rather than having to transition from potting mix into dissimilar native soil). Also, the ideal time to plant bare-root trees is in the winter, when you have a break from the demands of other garden chores.
Once the planting site has been prepared, it's time to select the tree. Trees with a trunk diameter between one-half and five-eighths of an inch usually become established faster than larger or smaller stock. If the root mass is visible, be sure it is well balanced, not “one-sided.” Remove any dead or damaged roots before planting. It is best to plant bare-root trees immediately after bringing them home, but if this is not possible, the roots should be covered with sawdust or compost and kept moist until planting.
Clear an area about 3 feet wide around the tree, eliminating weeds and grasses to keep them from competing with the tree for water and nutrients. To prevent future weed growth and conserve moisture, a layer of mulch 3 to 6 inches thick can be placed around the tree. However, to avoid crown rot, keep the mulch several inches away from the tree trunk. As a final step, remove the top of the tree by pruning back to a single trunk approximately 24 inches tall and paint the bark of the entire tree trunk with white interior latex paint diluted with water (two parts water to one part paint) as a whitewash to reflect excess heat. This prevents sunburn and the resulting invasion of wood-boring insects that can stunt or kill the new tree.
Autumn has finally arrived! We have shorter cooler days, and the leaves are turning brilliant Fall colors. Gardeners with some foresight and planning can use this time of year to plant bulbs for a riot of Spring flowers. With their potential for promised beauty, bulbs are like hidden jewels waiting to rise up when warm weather returns. The very act of planting Fall bulbs demonstrates one's faith in nature's cycles, where life begins anew when, eventually, Spring returns.
Botanically, these perennial plants are geophytes, adapted to store their nutrients and energy in underground storage structures. Tulips and daffodils are “true” bulbs (they have fleshy layers surrounding a central bud) and are perhaps the most commonly known. But plants that store their energy and nutrients in corms (bulbs that do not have layers) and in rhizomes (which have long, narrow underground stems that develop parallel to the soil surface) are also geophytes. All geophytes are adapted to produce new growth from these storage structures after periods of dormancy or environmental stress, such as drought or chilling.
Today, in addition to tulips and daffodils, bulbs often found for sale include alliums, fritillaries, snowdrops (Galanthus), snowflakes (Leucojum), grape hyacinths, and anemones. Commonly planted corms include crocuses and Dutch irises. Rhizomatous plants that can be planted in the Fall include peonies (typically planted as bare-root divisions), coral bells (heuchera), and bearded irises.
There are some basic rules to ensuring success with bulbs:
1) Plant at the correct depth, which is often listed on the bag they have come in.
2) Ensure they are planted with the growing tips pointing up and the roots heading downwards.
3) Plant in fast-draining soil, because most bulbs are susceptible to rot if they become water-logged.
4) Amend the planting soil with a mix of compost and, if planting in heavy clay, add some grit.
5) Place a layer of mulch over the area of newly-planted bulbs.
6) If necessary, secure chicken wire or plastic netting on top to keep pesky squirrels from digging the bulbs up. Small pieces of plastic fence netting secured over a planted container is often enough to discourage squirrels. You can adjust the netting in the Spring when new growth emerges. Doing the same in a yard is also possible, but more challenging.
Some gardeners go to elaborate lengths to keep their planted bulbs safe. Judging by the many beautiful displays of daffodils and other bulbs in local gardens each Spring, most bulbs do seem to survive, coming back year after year as “heralds of Spring”.
Mixing in a balanced fertilizer when planting can be beneficial, but there is no real scientific evidence that adding extra potassium to the planting holes will promote better blooms.
A fun planting technique is to toss out a handful of bulbs and plant them where they Fall. This approximates how these plants grow together in more natural settings. You can find special bulb planting tools to help you with digging the holes, often making the work much easier.
Once bulbs have finished blooming in Spring, wait until the leaves have completely dried before removing them. This allows the plant to make the nutrients it needs to store again for the following year's bloom. Some gardeners like to plant fast-growing annuals over their bulbs, or plant bulbs among perennials with Spring growth that will hide the drying bulb leaves and flower stalks.
Blue-eyed or yellow-eyed grass (Sisyrinchium), which grows from a corm, is easy to cultivate and establishes quickly, producing lovely violet-blue or yellow star-shaped flowers atop flowering stems. They are a member of the iris family and will readily spread if given some moisture.
Native bulbs are well-adapted to California's climate and growing regions and are especially beautiful when used in gardens and wildflower meadows that feature native plants.
The main requirements for growing bulbs, corms, and rhizomes include a cool, wet winter with little hard frost, well-drained soil, fairly deep planting and, most critically, total dryness all summer to avoid rotting. Native plant gardeners have had luck growing them in containers as well as the ground but some of these might need several growing seasons before you see your first blooms. If you are planting Fall bulbs to begin with, then you are already a patient gardener!
Planting Fall bulbs isn't simply a garden task, it's a gesture of hope and testament to nature's resilience. You are investing in the beauty of the future. Whether you are a seasoned gardener or a novice with a newfound passion for these plants, this simple act of tucking them into the earth, hidden away until they burst forth in Spring, is a connection to nature's cycles of life and renewal.
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.