How to Kill a Weed Tree without Digging

The problem seedling

How did a squirrel do that—bury a black walnut so close to our prized weigela that when the nut spouted, it grew up through the shrub in a way that digging it out would seriously damage the shrub?

Only a squirrel can answer that question. But I know that when I find a problem seedling here at Meadow Glenn, I put away my digging tools and go “nuke.”

This spring a large black walnut seedling grew rapidly through the edges of our ‘Wine & Roses’ weigela. I thought I had pulled out the seedling last year, but obviously I had left the roots intact. The two-year old walnut seedling would have a tap root a foot or more long. Trying to dig it out could do serious damage to our weigela.

So I adapted a trick I learned several years ago when invasive oriental bittersweet vine intertwined with our sweet autumn clematis.

Ready to paint

First I checked to see how the walnut was growing up through the weigela and figured out a way I could bend it out of the shrub and over the surrounding mulch. Next I stripped off all the lower leaves from the seedling, leaving a bare stem for about a foot from where it emerged from the ground. Then I bent the seedling to the ground and put a stone over the stem to hold it firmly in place. I then used a small, sponge-tipped brush to paint glyphosate concentrate (41%) on the leaves at the top of the seedling and on the leafless stem, being careful not to get any of the herbicide on the nearby weigela.

The job took about 15 minutes. Within hours, the seedling shows signs that it was dying as it absorbed the glyphosate. The photos tell the story. Photo 1 shows the walnut seedling growing up and through the weigela. Photo 2 shows the trimmed and “stoned” seedling. The stone, by the way, prevents the seedling from springing back into the weigela and perhaps seriously damaging the shrub with glyphosate. Four days later, Photo 3 shows the dead and dehydrating plant ready for me to cut to ground level and discard in the trash.

Four days later, the dead seedling

I don’t use much glyphosate, so when I do, I read the directions for use before I begin. And whenever I use any –cide, I put on cotton work gloves over which I put latex gloves. In warm weather my hands sweat profusely when I wear only latex gloves, but the cotton gloves under the latex gloves make them at least bearable.

Got a weed tree seedling that you don’t want to dig out? Paint it—carefully—with glyphosate.