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How to dispose of invasive plants

by Timber Press on May 2, 2013

in Gardening

Never burn poison ivy or poison oak, which release volatile oils that are harmful if breathed. Photo: Joseph LaForest

Never burn poison ivy or poison oak, which release volatile oils that are harmful if breathed. Photo: Joseph LaForest

Dead, nearly dead, yanked up, or poisoned plant parts present a disposal challenge for the home gardener. Please bear in mind that you do not want the refuse to regenerate somehow in your yard or wherever it is hauled off to. Otherwise, the infestation might return or pop up elsewhere—not good.


Dump or rake all debris into a municipal trash bag. Stuff tightly and chop up or shred as needed. Then, seal or cinch tightly. Some places allow heavy-duty plastic bags, others require biodegradable tall paper “leaf bags” designated and sold for organic waste. Either way, if possible, do not haul to the curb immediately. Instead, leave the bags in an out-of-the-way place for several weeks, safely sealed up, to allow the contents to dry out and perhaps even cook down a bit.

They are safe to discard when the contents are completely dead and rotted or dehydrated. The bags may also be less heavy after such a waiting period, which makes getting them to the curb or roadside, or into a truck, a bit easier. There may be a weight limit, such as 50 pounds, so bear that in mind as well.

Some municipalities compost yard waste; others incinerate such debris. Do not mix in other items, therefore, especially non-biodegradable trash. Some places charge to haul your bags away or to accept such materials at a transfer station. Therefore, it behooves you to dry out and condense the materials, and to use the right type of bag.


Here is a method that fails or is never even considered. Disposing pest plants in a compost pile simply helps them find a fertile growing substrate, utterly defeating the purpose, not to mention rendering your compost unusable when plant parts root or weed seeds germinate. Nevertheless, it can be done.

One option is if you have used another (nontoxic) method that you are certain has killed the torn-up plants, you can add them to a hot, “active” compost pile along with the things you usually add and wait for them to break down along with everything else.

Another option is to create a separate compost pile. For the contents to break down, it cannot be “weeds only”—you will need to do the same layering you employ in a regular compost pile. Intersperse the layers of weeds with “brown” or carbon-rich materials such as straw.

Warning: Composting weeds and invasives that have or might have ripe seeds is never a good idea. Some can germinate quickly, others can bide their time, managing to remain viable even when lodged in inhospitable conditions. A hot compost-pile temperature of 135°F to 150°F for about six to eight weeks is the minimum needed to kill most weed seeds, and that, of course, is not easily attained or sustained, even when you cover the pile.

To prevent its spread, cut back Queen Anne's lace before it goes to seed; to get rid of an infestation, dig up the plants by the roots and dispose of them properly.

To prevent its spread, cut back Queen Anne’s lace before it goes to seed; to get rid of an infestation, dig up the plants by the roots and dispose of them properly. Photo: Marci Lebrun


Another way to dispose of unwanted pest plants and their pieces is to dig a hole and bury them. Such a pit is best located in an out-of-the-way spot in the yard where it will not be tampered with and nobody will be tempted to plant over it.

Yes, a pit. A shallow grave will not do. To be extra-cautious, dig down at least 3 feet. Use a large plastic trash bag or those biodegradable autumn-leaf bags to line the hole, then pitch the leavings inside that and when full, seal it closed and cover over the pit with a board, flagstones, or old tires. This weights it down and marks the spot. Over time, the debris will rot and break down, losing volume, at which point you could add another load.


Where safe and legal (get a permit if required), you can get rid of a significant pile of weeds or brush from invasive trees and shrubs, including root systems, by burning. (Larger pieces are best chopped up into smaller pieces, if possible.) Make a bonfire and burn until everything is completely incinerated, then make sure to douse the embers thoroughly. Stomp on them, douse them thoroughly, dump dirt or sand on the site.

This method is fast and thorough. Just pick an appropriate and safe spot and be very careful. Basic safety tips include: do it away from buildings and overhanging vegetation; do it away from anything flammable (an open area of dirt or sand is best); keep the blaze small; keep several buckets of water and/or a primed hose close at hand; do not use anything flammable to kick off the fire (such as barbeque starter or gas), though a bit of shredded newspaper as kindling is permissible. Not all plants should be burned, however. Never burn poison ivy or poison oak, which release volatile oils that are harmful if breathed.


Some yards have a “back forty” or uncultivated area to the back of the property or behind a garage. If you have no particular plans for this area and will not be creating an eyesore visible from, or smell-able from, your house, garden, or the street, you could make a debris pile and leave it there. Assuming the stalks, branches, and yanked-out root systems are no longer alive, such a pile will slump and break down over time. Maybe a long time.

A precaution you might take is to spread the area first with an old tarp, plastic, or base of sand or gravel, then dump the refuse. When you transport material to the pile, drag it atop a tarp or in a large wheelbarrow to avoid any chance of spilling on the way over there.


Every garden shed should have a copy of this book. The wisdom that it wields will hold the invaders at the gate. — Roger B. Swain, host of The Victory Garden

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