Eradication of Juniper used in Landscaping

Asked April 22, 2013, 12:17 PM EDT

We cut some large Juniper shrubs that were used in the landscape. Now the roots have sprouted shoots all over the area we were hoping to use for a garden. It looks like grass!!!!! Any advice for how to deal with this? We want to do this following organic practices. If we have to use a non-organic herbicide, what should be used?

Multnomah County Oregon trees and shrubs weed issues

4 Responses

Good day and thank you for using Ask an Expert to resolve the challenge of dealing with that undesirable growth while using least-toxic methods.

I’m a bit puzzled by your question as few conifers re-sprout from the roots after the bushes/trees are removed. That didn't occur after I had an old, over-sized juniper hedge removed some years ago.

So, let’s begin by determining just what that new growth is. To do so, please attach several digital images to your response – one an overall view of the area, another a close-up of one or two sprouts.

I look forward to receiving your images, also to helping you resolve this issue in an ecologically safe manner.

Here are the photos of what I was told was juniper. This is a west exposure. I wonder if the amount of water the site absorbs is an issue.

Do you have any experience using acetic vinegar or limonene in situations like this?

Thank you for sending the images. They confirm my worst fears: The abundant new growth is field horsetail. The horsetail is sprouting for one of two reasons:
1. It was already present in your soil but was prevented from growing because of the dense shade cast by the junipers.
2. You added new soil, either purchased or “free,” which was contaminated by horsetail.

All in all, this is a bad news, good news story. The bad news is that horsetail is a persistent tough-to-kill weed. The good news is that you can win with persistent effort. But a caution: If you stop your efforts for a season, the horsetail will recover beyond your expectations.

“Field Horsetail and Related Species” contains extensive detail about this invasive perennial weed which goes dormant for the winter.

Your management choices are few and don’t include organic products. Whatever you choose, repeat applications will be required.

A. Dig to remove as much growth as possible, both above and below-ground. (The document referred to above illustrates the underground storage structures, some of which can be at considerable depths in established plantings.) If you use this method, it’s absolutely critical that you follow-up by removing all new growth every time you see it during the growing season, perhaps weekly. Your goal is to starve the roots. Repeated efforts will be required.

B. Apply the herbicide Casoron (active ingredient dichlobenil) according to the label directions during the late fall or winter. This product is a pre-emergent which will suppress growth of horsetail. It’s safe to use around woody perennials such as established trees but not around herbaceous plants such as vegetables or flowers. Repeat applications will be required.

C. Apply an herbicide containing the active ingredient of triclopyr. Several retail products are currently available, among them Brush-B-Gone, Cut Vine & Stump Killer, and Lily Miller Blackberry & Brush Killer. The label will have directions for safe use. Repeat applications will be required.

D. Combine the preliminary manual removal (as in A) with applications of either of the above herbicides according to directions.

Please recall this: Be persistent and you will win.

Thank you so much for your response and all of the information. Wanda Hoelting