Mulching Perennials
Trees and Shrubs
Trees and shrubs usually have an easier time getting through the winter if they are in good shape. However, if a freeze is forecasted, one of the most important things to do is to ensure they have been watered 2-3 days prior, especially if autumn has been dry. As with perennials, mulching with fallen leaves or other mulch will help protect the roots, but do not have mulch up against the tree trunk or plant stem, which could cause rot to occur.
Wrapping trunks of young trees with blankets, towels or piping insulation will provide added protection.
Bulbs
Wait until after the first frost, then gently dig up the bulbs or tubers. Cut away any leaves and brush off as much soil as possible. Let them dry out in a cool spot for about a week. Label them so you'll remember what they are! Pack them in a breathable box, such as a cardboard box, storing the bulbs so they don't touch each other, and cover them in sawdust or shredded newspapers. Keep them in a cool, dark location that is below 45°F, but doesn't freeze.
Citrus
Citrus plants can be protected by frost cloths which allow some light and air to penetrate and can stay on plants for a few days at a time. They can also lay directly on plant foliage. If you use other type of cloth such as burlap or cotton sheets, use stakes to hold the cloth away from the plant greenery. Remove it during daytime when temperatures are above freezing and sunny, and replace it each night prior to sunset. Whatever cloth you use, make sure the cloth goes all the way to the ground to capture radiant heat from the ground. If there is mulch around the plant, rake away during the day, if above freezing and sunny, to allow the soil to warm up.
Roses
Some roses are more sensitive to cold than others. As a group, hybrid tea roses are the most vulnerable. Make sure they are watered prior to predicted freezing temperatures, protect the root zone with mulch on the soil mound. You may also wish to cover your sensitive roses with frost cloths.
Container Plants
What do do if frost damages your plants? Wait!
Frost damage occurs when the water inside the cells of a plant freeze, causing damage to the cellular walls, which harms the overall health of the plant. Frost damaged vegetation will wilt, turning brown or black, as if they have been scorched. The bark may crack, or split. In severe or prolonged periods of frost the plant can die.
If you see what appears to be frost damage, wait until late spring until all chance of frost has passed. Plants are resilient and can often recover on its own, producing new growth. Pruning what seems to be damaged branches too soon can cause significantly more trauma, even death, to a vulnerable plant that might otherwise have recovered in the spring.
Resources
- https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22929
- https://sacmg.ucanr.edu/Frost_Protection/
- https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=45517
- http://ipm.ucanr.edu/PMG/GARDEN/ENVIRON/frostdamage.html
Denise Godbout-Avant has been a UC Cooperative Extension Master Gardener in Stanislaus County since 2020.
- Author: Ed Perry
During the first two to four years after planting a new fruit tree, fruit production is either light or absent. However, this is the time when major root growth takes place and the basic framework of the tree is being developed. Actually, the first year that the tree is in the ground is the most important for root development. Stress caused by diseases, nematodes, weed competition or insufficient water can slow or stop root development, and hence top development. If your tree's growth is stunted from the beginning, there is little chance that it will grow satisfactorily in later years. After the first years, young trees become more tolerant to many of these stresses.
The second and third growing seasons are critical ones for developing your tree's framework for fruit production. Deciduous fruit and nut trees must be properly trained for structural strength while developing maximum fruiting area. The system most used is the open center or vase system. Citrus and avocado trees, on the other hand, do not require extensive pruning. Pests such as twig boring insects that cause distortion of early limb growth are most serious during these early years, because their damage affects the ultimate shape of the tree.
Young trees are often most susceptible to certain diseases such as bacterial canker or verticillium wilt. If your trees reach eight or nine years of age without being badly injured by these diseases, chances are good that they will survive future attacks.
Of course the most common and serious cause of poor tree development is improper watering practices. Too much or too little water will prevent the vigorous growth of young fruit trees, and make them more susceptible to pest, disease and sunburn problems as well. More than any other cultural practice, irrigation will affect the growth, development, and long term health and productivity of your fruit trees.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
Learn more about planting and pruning bare root fruit trees by watching the recording of our past class on our YouTube Channel.
- Author: Ed Perry
If you do not prune your trees enough, they will become too tall to harvest, even with a tall ladder. If you have an unpruned fruit tree in your garden, you know that most of the fruit grows in the top. Yearly pruning is necessary to keep the tree at a reasonable height, for instance, no more than 10 or 12 feet high. If your tree is already overgrown, you may want to reduce its height gradually, say over a two-year period.
The main objectives of pruning mature fruit trees are to reduce the number and increase the size of the potential crop, to develop new fruit wood, to remove interfering and broken branches, and to contain tree height and spread for convenient harvest. Most fruit trees, when not pruned, produce more fruit than they can size and mature properly. You can prevent such overproduction with yearly pruning.
Persimmons, many figs, quinces and pomegranates bear fruit on current season's growth. When you prune these trees, remove old and weak branches, leaving some younger branches to produce new growth and fruit the coming year. Overcrowding and lack of sunlight will cause branches to die, so you need to thin out some branches to allow light infiltration into the tree so that the fruit wood stays healthy.
Nut trees such as almonds and walnuts do not need as much pruning for height control as fruit trees. You harvest nuts by knocking them down with a long pole, rather than by hand picking, so the trees can be much taller.
Fruit Tree Resources
Fruit Trees: Training and Pruning UC ANR Publication
The California Backyard Orchard For more details about training and pruning deciduous fruit trees.
Citrus and Avocado Trees Require Little Pruning For information on pruning citrus and avocado trees.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
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- Author: Ed Perry
We recently wrote the blog post “Wait! Don't Prune Apricot and Cherry Trees Just Yet,” to caution gardeners against pruning these trees in winter. Now we'd like to discuss when and how to prune avocado and citrus trees.
Avocados
Most avocado trees need little or no pruning. Whenever possible, allow them to develop naturally. Avocado leaves produce and store food for the tree. If this food supply is reduced by pruning, fruit production will also be reduced. Usually, removing dead or weak branches is the only pruning you need to do. Avoid pruning in late summer and early fall, as this stimulates new shoot growth that is susceptible to frost injury. In general, remove as few green branches and leaves as possible.
If you need to remove lower branches, prune them out completely, or cut them back to an upright growing shoot. Prune only after your tree has developed enough upper foliage to prevent sunburn damage on the lower limbs or trunk.
Sometimes a young tree grows tall without branching, grows sideways, or grows a top that is unbalanced. Correct these conditions by cutting the unruly limb or trunk back to a strong lower branch, or by staking the tree. Keep in mind that avocado trees grow naturally in an irregular way and will develop a better structure if they are not pruned at all. If you want to control the height, it's best to do so while the tree is young.
To prevent tall, upright growth, pinch back the terminal bud of the upright shoots on the young tree. Repeat this after each growth flush during the first few years. Your tree will spread out to the sides and develop a more compact form. If you reduce the size of an older tree by heading back large branches in the top of the tree, be sure to thin out the new growth which follows. Otherwise, the tree will soon grow back to its original height.
Citrus
If necessary, light pruning can be done in citrus trees any time of year. However, the best time to prune citrus is in early spring, after danger of frost has passed and before the start of spring growth.
Nearly the same rules for avocado trees apply to pruning citrus trees. The foliage of a citrus tree is an important food (carbohydrate) storage area. Pruning removes foliage and stored foods and causes the tree to produce a flush of vegetative growth instead of fruit. For the most part, prune out only dead or broken limbs.
Citrus trees normally produce vigorous shoots from the base of the tree called suckers, which you should remove as they grow. Vigorous shoots that grow from branches are called watersprouts. Remove watersprouts if they are not well placed but leave them whenever possible. Young trees need no pruning for the first two or three years after planting, except to remove suckers. As the tree grows older, prune lightly only to remove branches which are too closely spaced or entangled. Do not remove low-hanging branches, as they bear fruit within easy reach and shade the trunk and soil. The ideal citrus tree has a skirt of foliage that extends almost to the ground. Left alone, citrus trees normally develop an even, round-headed shape as they mature.
Lemons usually need a bit more pruning than other types of citrus. Cut back some of the more vigorous shoots on young trees. Lightly thin the branches of mature lemon trees each year to improve the size and quality of the fruit.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County.
- Author: Anne E Schellman
Have you ever seen a tree that looks like it got a bad haircut? Or was just plain unattractive? Chances are this tree was pruned incorrectly using a practice called topping. Topping is the harmful practice of cutting tree branches to stubs, causing the resulting growth to become bushier and more susceptible to breakage during storms.
In winter, the results of tree topping are easier to see. Instead of topping, consider the form of the tree and picture how you want it to look when you are finished. Here are a few things to know before you start:
- Pruning cuts create a new direction for a tree to grow.
- There are three types of pruning cuts—a thinning or reduction cut, a removal cut, and a heading cut. Each is distinctly different and is used to accomplish unique objectives
- If you prune correctly, you can “train” a young tree into an attractive form.
- Pruning to establish a strong and attractive form is best done during the first 3-5 years of a tree's life.
- Reducing the size of a large tree can be done but is usually best done by an ISA certified arborist.
- Incorrectly pruning certain fruit trees can result in trees that don't bear fruit!
Here are some resources that describe the best methods to prune landscape trees and fruit trees.
Landscape Trees
Training young trees
Thin, don't top mature trees
Pruning landscape trees
Fruit Trees
The California Backyard Orchard website lists fruit trees by species and includes pruning tips for both deciduous and evergreen fruit trees.