- 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: Lisa Cherenson
Fields of weeds abound
Challenge faced with sturdy hoe
Sweat, aching back-Spring!
Purple hues, blue sky
Buzzing bees laboring-gentle hum
Soul food-Lavender!
Lisa Cherenson 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.]
/h2>/h2>/h2>/h2>/h2>- Author: Anne E Schellman
The University of California Cooperative Extension (UCCE) Master Gardeners of Stanislaus County are teaching a free Managing Pests in Your Vegetable Garden class on Thursday, July 18, 2019 from 6:00-7:30 p.m. at the Agriculture Center on 3800 Cornucopia Way in Modesto at Harvest Hall, Rooms D&E.
Join us for a free class about common pests that plague warm-season vegetable gardens. Learn how to identify insects, diseases, and weeds and how to control them using less-toxic methods.
This family-friendly class is open to everyone. Participants will receive free seeds (while supplies last). Our instructor for the class is Ed Perry, Environmental Horticulture Advisor (emeritus) for Stanislaus County. This class is free, but please visit http://ucanr.edu/vegpests2019 or call Anne Schellman at (209) 525-6862 to sign up. Space is limited, so please reserve your seat today.
If you haven't already, please “like” us on Facebook and Twitter @UCMGStanislaus so you never miss an announcement for a class or workshop.
- Author: Anne E Schellman
Weeds may grow more slowly this time of year, but they can still be a problem. Most of the weeds found in gardens and landscapes now are winter annuals. These weeds germinate in late summer or fall and grow during cool weather.
Annual weeds flower and set seed in spring and die in summer. Some of these weeds can produce hundreds to thousands of seeds per plant! As you may imagine, these weeds can quickly become difficult to control once established. The best time to control weeds is when they are small, before they bloom and set seed.
Manage annual winter weeds by hand pulling or hoeing, making sure you remove the entire root. Once you've cleared an area, apply 3-5 inches of mulch. Monitor your landscape weekly, pulling any weeds that emerge. Be aware that organic mulches break down and must be replaced every few years.
Young weeds in open areas can be killed using a small flaming tool. You can find these at local hardware stores or nurseries. In difficult cases where you have trouble getting control, you may want to use an herbicide. Be sure to identify your weeds before choosing a product. Read the label before application and follow directions carefully.
If you aren't sure what weeds you have in your garden, you can bring in samples to the Stanislaus UCCE Master Gardeners. Reach us at (209) 525-6800 or visit our office between 8:00 a.m. and 4:30 p.m. Monday through Friday, at the Agricultural Center on 3800 Cornucopia Way, Ste A in Modesto, 95358. You can also email photos to ucmgstanislaus@ucanr.edu.
For more details on weed control, consult the following UC IPM Pest Notes: Weed Management in Landscapes and Weed Management in Lawns.