Applying mulch every spring makes sense on several levels. It helps enrich the soil and helps retain moisture during the dry summer months. But the main reason most of us mulch is weed control. We faithfully lay down a couple of inches of mulch and cross our fingers that we’ve won the battle. But most of us aren’t so lucky: weeds almost always find a way to pop up, even in the most beautifully mulched landscaping. Why are weeds so hard to tame, and what can you do to stop them? Here are a few tips:
Why Do Weeds Grow In Mulch?
As experienced gardeners know, fighting weeds is a never-ending battle. They seem to pop up no matter what you do. But there are proven strategies for preventing them, and mulch is one of the best tools available. Working with a professional for your landscaping needs, including mulch application, is the best way to make sure your weed control program works.
How Can I Kill Weeds in Mulch?
If weeds start popping up in mulch, we want to tackle them before they can seed and spread. If you’re pulling weeds by hand, make sure you get the whole weed, including the root. Applying a pre-emergent herbicide is also an option. One approach is a commercial weed-killer like Roundup, which contains the chemical glyphosate. Some gardeners prefer a more natural approach, using a mixture of vinegar, salt, and dish soap to kill weeds as they grow.
2250 Agate Ct.
Simi Valley, CA 93065
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Yes, you can. Synthetic landscape fabrics provide a physical barrier to weeds yet allow air, water and nutrients through to plant roots. Spread the fabric over bare soil around trees and shrubs; overlap several inches of fabric at the seams. Anchor the material with U-shaped metal pins, then conceal it with 1 to 2 in. of mulch, such as stone or bark chips.
Frequent, light watering causes shallow roots and helps annual bluegrass, crabgrass, chickweed, sedges and other weed seeds germinate. If you water too little, the lawn suffers while spotted spurge, Bermuda grass, quackgrass and other weeds adapted to drier soil thrive. Instead, provide your lawn with infrequent, deep soakings. Lawns need about 1 inch of water per week. Set an empty tuna can on the lawn to determine when you have applied 1 inch of water.
Preemergence herbicides, such as those containing oryzalin or trifluralin (look on the label for these chemicals), or nontoxic corn gluten meal, kill weeds just as they germinate and will not eradicate established weeds. For a preemergence herbicide to be effective, you must apply it to soil cleared of visible weeds; also, you have to water most of these herbicides into the soil.
Where to Find It
True Temper Hardware
Camp Hill, PA 17011
Any weeds that grow through mulch are easy to pull because the soil remains loose. Photo by Saxon Holt
Too little fertilizer can lead to sparse lawn that loses the competition with weeds. Too much helps nurture certain weeds, notably annual bluegrass, Bermuda grass and crabgrass. Strike a balance by following the application rates on the package. And use a fertilizer with a high percentage of controlled-release nitrogen, such as sulfur-coated urea, ureaform or IBDU. These provide a slow, steady nutrient supply.
Water Grass Infrequently and Deeply
Irrigation & Green Industry Network
916C N. Formosa Ave.
Los Angeles, CA 90046
Check the label to determine if it is safe for use around the kinds of landscape plants you have and effective against the weeds normally present.