Mechanical removal of weeds can be accomplished by hand-pulling, hoeing, or tilling. Even though hand-pulling weeds can be tedious, if done on a regular basis before weeds go to seed, it is the least disruptive weed control method in established plantings.
Hand-pulling works with either annual or perennial weeds, as long as you catch them in the seedling stage. It can be difficult to pull out the entire root system of an established perennial, and if you don’t, it can sprout again from the root or crown. Never leave annual or perennial weeds on top of soil or use as mulch after pulling because some persistent weeds can re-sprout from root crowns and root systems left on the ground.
Annual weeds that haven’t gone to seed can be composted, but perennial weeds should always be discarded in the trash. Hoeing and tilling are alternatives to hand-pulling, but care must be taken around established plantings so you don’t disturb or destroy the roots of desirable plants.
Mulches should be used around landscape plants to inhibit weeds and conserve water. Mulches can be organic materials such as composted wood chips, pine needles, or grass clippings, or they can be inorganic materials such as crushed stone or gravel.
Weed seedlings that do come up in mulched areas are much easier to hand-pull, as long as you catch them early. Organic mulches will need to be refreshed regularly as they slowly decompose. Do this by roughing up the old mulch and adding a light layer of new mulch over the top. Inorganic mulches need to be replaced infrequently.
Landscape fabric is another effective method for controlling weeds, but its use around landscape plants is controversial. It can interfere with air and water infiltration, and it may inhibit return of organic matter from decomposition of organic mulches to the soil.
Fabrics also can girdle trees as they grow and trunk girth expands. The best use of landscape fabric is beneath 3 to 4 inches of mulch in unplanted areas like walkways, where they can form an effective barrier to weed growth.
The weed control method of last resort should be herbicide use. Of the many options available, pre-emergent herbicides and products containing glyphosate are among the safest and most effective. Pre-emergent herbicides are moved into the soil and activated by moisture. If they are applied in late fall or winter, moisture from either rain or snow precipitation should be adequate to activate them. If precipitation does not occur within three days of application, 1 to 2 inches of water should be applied to treated soil.
Areas of your garden that are watered infrequently or not at all may not receive the full benefit of pre-emergent herbicide application unless you remember to water them in soon after application. Pre-emergent herbicides work by killing seedlings as they sprout, but they will eliminate all germinating plants, not just weeds. Use a pre-emergent herbicide only in areas that are, or will be, planted with rooted plants.
Do not use them if you rely on self-sowing plants to fill in gaps in your perennial flower beds. Glyphosate products eliminate both grasses and broadleaf plants, and are applied directly to emerged, actively growing weeds. Glyphosate takes 7 to 10 days to have an effect.
Do not allow glyphosate-containing products to contact desirable plants, and do not spray under windy conditions because spray drift can also cause unintentional damage to desirable plants. Always read the label for safe and effective use.
All plants require nutrients to grow and remain healthy, but many drought-tolerant native and adapted plants can get all the nutrients they need from a properly maintained soil environment.
Many of our urban landscape soils, however, have been stripped of organic matter and the soil structure disturbed to the point where nothing but the most persistent weeds will grow. For this reason, it is a good idea to have your soil tested prior to installing landscape plants.
In most cases, amending soils with composted organic matter prior to planting will improve the fertility of your soil. Adding organic mulch to planted areas also helps to improve soil fertility over time. If part of your garden will be comprised largely of drought-tolerant native plants, organic amendments may be all they need to thrive.
Over-fertilizing these plants only weakens them and results in rank, unsightly growth. In fact, many of the penstemons and desert-adapted shrubs like Chrysothamnus nauseosus (Rabbitbrush) and Fallugia paradoxa (Apache Plume) thrive on neglect and require the excellent drainage provided by inorganic rock mulch and little to no supplemental fertilization.
Knowing the habitat your plants are adapted to is critical to understanding your plant’s needs. If you don’t know, err on the side of less rather than more nutrients, and watch plants closely throughout the growing season for signs of deficiency.
Nutrient-deficient plants may develop yellow or discolored foliage. If this happens, simply add organic matter or a controlled-release type of complete fertilizer around the root zone, water in thoroughly, and watch for improvement.
Other factors may affect the availability or movement of nutrients through the soil. Plants in sandy soils may need more frequent fertilization than plants in loamy or clay soils. Soils that are alkaline (high pH) may bind essential nutrients and make them unavailable.
A soil test will provide this information and make recommendations for amending the soil. An alternative to soil amendment is to choose plants that are adapted to these conditions. Utah soils are often alkaline, and textures can range from rocky or sandy to silty loam or clay.
Book NowFortunately, plants native to our region have adapted to these conditions, and you can choose from a variety of native plants to fill almost any microclimate in your landscape.
The key is to learn as much as you can about your yard and your plants. Paying attention to the needs of your landscape plants will make you a more successful gardener.
Periodically, you will need to control the growth of your landscape plants by pruning, pinching or deadheading, and dividing. These activities will maintain your plants’ health and appearance by removing dead or undesirable growth, and by stimulating, reinvigorating, or re-directing their growth.
Some locally adapted native plants may quickly grow out of their space when provided with the relatively abundant resources available in a managed landscape. An example is Gutierrezia sarothrae (Matchbrush). Withholding water or nutrients will keep growth of this species in check.
Pruning is a way to control growth on trees and shrubs. Many forms of pruning exist, and the kind of cut you make depends upon the desired result and the growth habit of the plant.
Thinning cuts are made by cutting a branch back to its point of origin. The point of origin could be another branch or the main trunk, or it could be near the ground. Thinning can be used to shape or direct growth, but most often it is used to reduce bulk and restore the natural structure of the plant.
A heading cut is more severe than a thinning cut, and removes part of a branch leaving a short stub above a bud. This type of cut stimulates a profusion of twiggy growth from a lateral bud just below the cut.
Sometimes it is mistakenly used when a thinning cut would have been a better choice. Overuse of heading cuts can ruin the natural shape of a tree or shrub.
Shearing is the most severe type of heading cut and involves cutting a plant’s outer foliage to create an even surface. Only certain trees and shrubs will benefit from this type of cut.
Shearing can be used to create a hedge or screen with closely spaced plants. Some woody plants can be treated like herbaceous perennials and sheared almost to the ground to control their growth or to restore them to a more natural shape. Most pruning should be done in late winter or early spring before spring growth begins.
For plants that flower on last year’s growth, prune after flowering. With only a few exceptions, most native conifers require no pruning. For example, junipers are highly valued for their natural shape. Junipers that have outgrown their space should be removed rather than pruned.
The bloom time of some annuals and herbaceous perennials can be extended by removing flowers as soon as they start to decline. This is called deadheading, and some plants can be stimulated to repeat bloom when you remove the spent flowers.
In the case of plants with a flower on a single stem, cut back the entire stem to avoid a gangly, headless stem. If you don’t deadhead plants that repeat bloom, the plant will set seed, signaling the end of flower production for the season.
Some herbaceous perennials can be sheared by one half to two thirds after they have gone dormant in the fall. This will remove unsightly stems and rejuvenate plants that have become gangly and have reduced flowering.
Consider delaying cleanup until late winter for plants that have persistent and attractive stems and seed heads. Plants like Gaillardia (blanketflower), Astilbe (false spiraea), and many native grasses can add structure, texture, and color to an otherwise drab fall/winter landscape.
Division is another way of rejuvenating herbaceous perennials that have become weakened by age or overgrowth. A sign that your plants need dividing is when flower production is reduced and the stems become thin and nonproductive.