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: Heidi Aufdermaur
The Master Garden handbook defines a weed as “a plant growing where it is not wanted.” For the home gardener, a plant can become a weed when it interferes with intended use of land and water resources.
I recently purchased “Weeds of California and other Western States” a two-volume resource book. It lists over 1600 pages of plants considered weeds. As I read through this book, I see many plants listed that I would not have considered as weeds, such as the broadleaf forget-me-not. I love the look of this annual. I scattered their seeds several years ago in one area of my yard and this year I found them growing in several other places. This isn't surprising as I've observed their seeds attached to my clothes and garden gloves.
So, is it a weed if this pretty flower shows up somewhere else? According to the California Invasive Plant Council, the answer is “yes,” since this particular plant is also considered invasive. It can escape landscapes and move into natural habitats and pastures. The control of invasive plants in California costs over $82 million dollars per year.
Nostalgic Weeds
One “weed” I enjoy came from my grandmother's garden, it's called the “three-corner leek”. This “weed” looked so pretty in her yard, I brought it home many years ago. Now, I see it made itself comfortable all over the yard. This perennial bulb, with white umbel-like flowers, has “escaped cultivation as a garden ornamental”, according to the “Weeds” book. It has been somewhat easy to control, and I dig out the bulb when it appears. I think of Grandma when I see it, so in the garden, it's staying.
A Weedy Menace
I am slowly winning the fight in two areas where these weeds are located. However, under the birch trees, I have surrendered to taking my garden knife and cutting off the greens just below the surface of the ground. I know it may not be a permanent solution, but it looks good until I need to cut the greens again, in a few weeks. The “Weeds” book says this process eventually “depletes bulb energy reserves.” I have learned not to let this plant set flowers as it also reproduces itself using seeds.
I am determined to win this battle against the weeds with perseverance. Wish me luck!!! I hope to see your comments on how you are doing controlling weeds in your garden.
UC IPM Home and Landscape Pests - Weeds
http://ipm.ucanr.edu/PMG/menu.weeds.html
California Invasive Plant Council
https://www.cal-ipc.org/
Weeds of California and Other Western States, vol. 1&2, UC ANR publication 3488
http://anrcatalog.ucdavis.edu
For more information about Stanislaus Master Gardener's program and upcoming classes, sign up for the Stanislaus Sprout blog at https://ucanr.edu/blogs/StanislausSprout
A Help Desk is also available to help with other gardening questions or concerns: https://ucanr.edu/sites/stancountymg/
Heidi Aufdermaur is a graduate of the 2019 Class of Master Gardeners in Stanislaus County.
- Author: Cheryl A. Wilen
Nurseries and garden centers often sell a wide range of plants for use in gardens and landscapes. As a consumer, you may manage a complex array of different landscape plantings, including woody trees and shrubs, woody ground cover beds, annual flower beds, herbaceous perennial beds, and mixed plantings. This complexity often makes weed management difficult. An integrated approach is the most economical and efficient way to control weeds, so knowing strategies for managing weeds in a variety of landscapes can help.
Woody Trees and Shrub Beds
Control perennial weeds before planting, although weed control can also be done after planting. Densely planted areas will reduce weeds. Geotextile (landscape) fabrics rather than black plastic used with a shallow layer of mulch will keep weeds from emerging. If you mulch without a geotextile base, the mulch layer must be thicker to prevent weed emergence.
If needed, you can use a preemergence herbicide to control annual weeds and supplement with hand weeding and spot applications of postemergence herbicides for weeds that are not well-controlled by hand weeding, such as perennial grasses.
Woody Ground Cover Beds
Mature, woody ground cover beds should exclude most weeds; however, when ground cover is just establishing, weed growth is likely. Perennial weeds must be controlled before planting, although perennial grasses may be selectively controlled after planting with a grass-selective herbicide like sethoxydim (Grass-Getter). Annual weeds may be controlled with mulch plus a preemergence herbicide but rooting of stolons in new plantings may be affected. You will need to supplement with some hand weeding.
Annual Flower Beds
A dense planting in annual flower beds will help shade out and compete with many weeds. Flower species should be carefully selected for weed management compatibility. Periodic cultivation at 3- to 4-week intervals and between flower beds plant rotations will also suppress weeds. Perennial weeds must be controlled before planting. Annual weeds can be controlled with mulches, preemergence herbicides, frequent cultivation, and/or hand weeding. Control perennial grasses with grass-selective herbicides like clethodim, sethoxydim, or fluazifop. Avoid nonselective herbicides in annual flower beds after planting.
Herbaceous Perennial Beds
Weed management options in herbaceous perennial beds are similar to those for annual flowers, except that it is more important to eradicate perennial weeds as there will be no opportunity to cultivate or renovate the bed for several years; and fewer species are included on herbicide labels. Geotextiles may be used in these types of plantings. Manage weeds with mulches and supplement with hand weeding. If needed, use preemergence herbicides after hand weeding.
Mixed Plantings of Woody and Herbaceous Plants
Weed management in mixed plantings is complex because of the diversity of species. Different areas of the bed could receive different weed treatments. Site preparation is critical because post-plant herbicide choices are few. Plant the woody species first and control perennial weeds in the first two growing seasons, then introduce the herbaceous species. Plant close together to shade the soil. Group plants within the bed that will receive similar weed management programs.
In most landscape situations, herbicides should not normally be needed by home gardeners. Mulching, removal by hand, and proper irrigation (pattern and amount of water) are sufficient in most cases. Find more information in the UC IPM Pest Notes: Weed Management in Landscapes.
[Originally published as "Managing Weeds in Landscapes" published in the Fall 2018 issue of the Retail Nursery and Garden Center IPM News.]
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