Overspray

Overspray, drift, or carryover occurs when herbicide from neighboring property reach your plants. It rarely ends well, and it can make for strained relations. And sometimes you do it to yourself.

Those pesky weeds coming up through the patio blocks or on pathways are a pain to dig out. One quick spray and they are gone. Right? Wrong. But there is a slightly easier way, so read on!

Very often, overspray is accidental. A quick breeze blows in, the temperature shifts, or your happy canine wags through the garden. In other cases, overspray is due to thoughtlessness, ignorance, or vandalism. From your point of view, it makes no sense. One day, your plants are thriving. The next day, something is wrong.

Symptoms of herbicide damage

The symptoms of herbicide damage vary, depending on the chemical used. Broadleaf weed killers cause leaves to twist and cup. New leaves narrow. Also, the roots of annual plants will come closer to the surface than is good for them. These herbicides will, as advertised, cause grasses to turn yellow and die. Non-selective herbicide overspray will cause chlorosis, poor health, dieback, and death. Other symptoms of herbicide overspray include leaves turning purple, stem dieback, and leaf mottling and spots. These symptoms can indicate other problems, too, so diagnosing overspray can be challenging.

How overspray occurs

Sometimes the best indicator of a problem is seeing your neighbor applying chemicals the day before. Most herbicides are sprays. And that vapor can spread to areas unintentionally, especially if there is a breeze, low humidity, or high temperatures. Herbicides can travel for miles on the wind. And those convenient handheld spray bottles look safe, don’t they? But, when you squeeze that handle, it is too easy for the spray to bounce off your intended target, the soil, or your shoe and land elsewhere. That contaminated shoe can now carry the herbicide to new plants. After an intentional application, the surrounding soil also contains herbicides. This soil can be scattered, tracked on the sole of a shoe, moved around on gardening tools, or carried on a breeze to places where herbicides are not wanted.

Preventing overspray

There are several ways you can prevent overspray from damaging or killing plants you never meant to harm:

• ALWAYS FOLLOW PACKAGE DIRECTIONS EXACTLY. EVERY TIME. NO MATTER WHAT.
• Communicate with neighbors about what chemicals are being used, when, and how.
• Identify plants sensitive to overspray and use less damaging herbicides (or none at all) in those areas.
• Leave buffer zones between treated and untreated areas.
• Do not apply herbicides while the wind is blowing.
• Do not spray if temperatures are unstable. Thermals can carry chemicals the same way the wind does.
• Use low-pressure nozzles to reduce the number of tiny droplets that are more likely to travel.

Treating victims of overspray

Large perennial plants can often be saved from the effects of overspray if treated soon enough. The chemicals move more slowly through the vascular tissue of these larger plants. Remove any leaves that have come in contact with an herbicide to halt the spread of the chemical. Rinse plants off with a hose and water them well. Of course, the water that comes off the plant will contain herbicides, which can then spread to new locations. [Oh, what a tangled web we weave…] 

Anyway, watering the plant will help to dilute the chemicals. These plants will require special care for at least a year. Left untreated, they will eventually die. Dispose of tender annuals and edibles affected by overspray in the trash (not the compost pile). Even though you might be able to keep these plants alive, do you want those herbicides in your food?

Finally, you are legally liable for damage caused by overspray, even when unintentional.

As for those pesky sidewalk weeds, grab a sharp knife or screwdriver and cut them off at ground level. Then, pour a liberal amount of vinegar over the area. It may not kill the root, but it will take the plant a lot longer to return if it does at all.