This time of year, we begin getting questions from homeowners about controlling weeds in their lawns.

There are two characteristics of herbicide that are important to understand –– selectivity and persistence.

In terms of selectivity, you need to choose between an herbicide that selects for broadleaf plants (as opposed to grasses) and an herbicide that will kill any plant it comes in contact with. Dicamba and 2,4-D are broadleaf-selective herbicides that, at appropriate rates, target broadleaf weeds and leave grasses alone.

Both are best used when weeds are growing and active.

Persistence refers to how long after an application an herbicide will continue to suppress weed germination, emergence and growth. Neither Dicamba nor 2,4-D are especially persistent.

But if you take 15 minutes every weekend in the summer to walk around your lawn and spot-spray weeds with these chemicals, it is well worth the time invested.

There are many herbicides for agricultural use that offer persistent control of broadleaf weeds. However, these products are not labeled for lawn use.

If a homeowner were to make a mistake, there could be a bare patch in the yard that you would have to live with for years. For this reason, I would advise the amateur to avoid the purchase and use of persistent herbicides for lawns.

Roundup (glyphosate) is the most common broad-spectrum herbicide used on lawns and yards. It is a great tool for knocking down weeds growing in gravel or cracks. Do not use Glyphosate in your lawn or you will kill your grass and more weeds will take over.

Roundup begins to deactivate as soon as it touches soil. You will only control the plant that you have applied it to. To get season-long control and to suppress a seedbed of weed growth, try Imazapyr.

A spring application of Imazapyr on a gravel pad should suppress weeds all season long. Again, if you make a mistake with Imazapyr, you will have to live with it for a long time.

Double-check that you are applying at the proper rate and that you are avoiding spray drift when using this chemical. Lastly, do not spray Imazapyr under the drip line of trees and shrubs.

These easy-to-use products containing the above chemicals are available at Grain Growers and Ace Hardware.

Broadleaf Selective: Ortho Weed-B-Gone, Green Thumb Lawn Weed Killer

Broad-Spectrum Short-Persistence: Roundup, Green Thumb Weed and Grass Killer

Broad-Spectrum Long-Persistence: Ortho Ground Clear, Green Thumb Vegetation Killer

Remember, herbicide is only one part of a toolkit needed to get your lawn looking good weed-free. Proper seeding, watering, and fertilizing are all essential components to achieving that thick mat of green grass to enjoy throughout the summer.

Don’t hesitate to contact us with any questions.

Ryan Oberhelman is Wallowa County Vegetation Manager. He can be reached at 541-426-4543, Ext. 206.