Question: I have a home in the country that borders other homes and agricultural land. I need to control invasive weeds on my property but want to be a good neighbor. Please share a few tips on how to safely use herbicides.
Answer: Many horticultural crops like wine grapes, blueberries, filberts, vegetable crops and hemp have increased acreage rather dramatically over the past 10 years.
These farms are spread throughout the county where they are often planted next to rural homeowners. A large percentage of our county population resides in rural areas where we enjoy life by raising gardens, fruit tree, and livestock. With such a wide variety of crops being grown across the county it is not surprising that every year I get a number of requests to check on crop or landscape damage that has been caused by herbicide drift as people strive to control aggressive, invasive weeds.
What is herbicide drift? It is when chemical weed control products miss their intended target. Herbicide drift is generally caused by spraying in too strong a breeze, typically above 9 mph. Drift is compounded by spraying when the temperature exceeds 70 degrees, with humidity below 40% and your sprayer is creating very fine droplets that vaporize.
Another type of drift can occur after you have sprayed the target plant and the chemical volatilizes and leaves the plant during the high temperatures of summer.
If you live in the country and are near a vineyard, orchard or any horticultural crop field you must be very careful when you decide to spray herbicides on your property. Herbicide drift can be very damaging to crops, causing growers great economic harm and significant liability to the sprayer.
I would recommend to all parties, whether you are a grower or the neighbor to a grower, that you put away the herbicides during the heat of summer, especially in July, August and warm weeks of September.
During the fall, winter or spring — when the weather is cooler — look for herbicides that are formulated to have low volatility. For example if using 2,4-D, use the amine form.
Stay away from using the ester formulation of 2,4-D in warm weather, which is highly volatile. Better yet is to keep your fence rows, fields and yards clean year around with a combination of selective translocated herbicides for grasses or broadleaf plants in the cool fall or spring season.
Once your target areas are clean, use pre-emergent herbicides that are sprinkled or sprayed on the soil in the fall or late winter to keep them clean. Be careful with the pre-emergent herbicides near shrubs and trees since they can leach a little into the root zone.
Always read the label and follow directions carefully before using herbicides.
A good plan for controlling weeds on your small acreage near sensitive crops is to target weeds when they are very small during fall or late winter when we have a few dry days. Seedling grass and broadleaf weeds can be controlled very easily by using Glyphosate.
This fall has been a bit dry but has allowed an excellent opportunity to control weed seedlings with a cool season application of herbicide. If you didn’t get your weed sprays on yet, look for a three to four day break in the weather to do the job. As long as the weather is mild enough to allow weeds to grow, the herbicides will be effective.
If you need to go after blackberries or poison oak, use a brush killer with the active ingredient triclopyr in early spring when they start growing. If you need a follow up, use Roundup in the fall after most crops have finished growing.
For those of us living in towns, it is a good idea to follow the same guidelines for herbicide drift prevention and seasonal use limitations. If you want to continue to be a good neighbor, always be aware of the sensitive crops your neighbor grows just on the other side of the fence from your property.
Over the years we have seen a lot of damaged grapevines, tomatoes and roses at our OSU Extension office.