We’ve all heard that expression…April showers bring May flowers. But not all flowers are desirable. Your yard might be full of unwanted flowers right now, in the form of dandelions, thistles, henbit, and other blooming weeds. Spring is the time of year when homeowners all across Texas are pulling out their wand applicators, broadcast spreaders, and over-the-counter herbicides, often blissfully unaware that their annual war on weeds may end with some unintended major casualties.
HOW WEED CONTROL HURTS TREES
You may have noticed that weed control products are often labeled for use on “broadleaf” species of plants. That’s plant lingo for any type of plant with flat leaves…. Again, that’s any PLANT with flat leaves, not any WEED with flat leaves. Which means trees with flat leaves (i.e. any tree that’s not a conifer) can be harmed by these products, too.
Most herbicides meant for use on broadleaf plants work in one of two ways: 1) disrupting cell division, so the plant literally can’t grow, or 2) inhibiting photosynthesis, so the plant can no longer produce the sugars it needs to live. It’s easy to see how these effects could prove harmful for trees, and not just weeds.
Sadly, most if not all products labeled as “weed and feed” (often preferred by homeowners for the convenience factor of being two-in-one) contain products that could kill your trees.
OTHER FACTORS TO CONSIDER WHEN USING HERBICIDES
It’s vitally important to read the labels of these products and use them correctly. Literally everything you need to know before applying them is on the label — easy peasy.
Young trees are susceptible to damage from herbicides, as are trees in early spring that are just leafing out for the season. Using too much of these chemicals, or accidentally applying it to a tree’s foliage, can also cause damage. Even applying them in the wrong weather conditions can be dangerous - high winds can cause what’s called “drift” where the herbicide is spread by the wind, and rainwater (or hose water) runoff can carry herbicide where it shouldn’t go even long after it was initially applied. Some chemicals can even accumulate in the soil and be absorbed through a tree’s roots
Frequency of use is another important factor. Some trees might take a hit from these chemicals once and not be affected, but if weed killers are applied more than once in a season or for multiple years in a row the trees are more at risk of sustaining damage.
SAFE WEED CONTROL ALTERNATIVES
So how can you maintain a lush green weed-free without risking the health of your trees?
There are organic weed-killing alternatives, usually vinegar-based. While some anecdotal evidence says they might require more frequent use than chemical herbicides, they are effective, fast-acting, and definitely won’t kill your trees. If you’re more the DIY type, there are options you might find around your home, as well. Vinegar-based weed killer? Well, how about just plain old vinegar? Your standard, garden-variety vinegar will do the trick for for weeds that are just starting to grow, but for the tougher culprits you’ll want something more concentrated, like pickling vinegar. As an added bonus, it makes for a decent ant deterrent.
Salt water can be effective, as well. Two parts salt to one part water. However, this is best reserved for sidewalk cracks, decks, and so on, rather than on your actual lawn. You’ve heard the expression “salt the earth”? Too much salt in the soil and it won’t be just weeds you’re getting rid of.
The last tree-safe method we’ll talk about is solarization. This process is slow, but dead simple. Secure a clear, plastic tarp over the area of weeds you want to kill, and…that’s it. Wait a couple of months. The sun’s radiant heat through the clear plastic will suffocate and sterilize the soil beneath. Finally, good, old-fashioned weed pulling by hand is always an option. Labor intensive, sure, but in the right circumstances (and with the right lawn), the old ways can be the best. There are tools available to make weeding a bit easier, though, such as dandelion forks.
GREAT, BUT I’VE ALREADY BEEN USING BROADLEAF HERBICIDE INCORRECTLy!
Call your friendly neighborhood Arborist! Depending on the strength and frequency of the herbicide, there may still be ways to strengthen your tree to help it weather the negative impacts of the herbicide.