We are all spending more time at home right now, and many of us are finding ways to stay busy by working on projects we never had time for before. Perhaps you are engaged in a battle with weeds on your property that you have been meaning to get to for a while, or doing routine maintenance on a familiar infestation. This is a good time of year to tackle many weeds that have recently germinated and perennials that haven’t produced seeds yet. The soil is moist making roots easier to remove. But what to do with all the plant material you are removing, especially if we must avoid going anywhere?
Usually we recommend that regulated noxious weeds should be put into the garbage or large loads can be taken to the transfer station and other weeds can be put in yard waste bins or disposed as yard waste at the transfer station. However, this becomes a challenge while we are all staying home as much as possible. If you have a lot of weeds that you want to throw away, but cannot get to the transfer station right now, here are some suggestions for disposing of weeds in ways that prevent them from spreading to new areas, including some creative solutions to meet our unique circumstances due to the COVID-19 outbreak.
First and very important, never toss weeds into natural areas or empty lots. Many can continue to grow and spread onto neighboring properties. They might even make their way back under the fence into your own garden.
If you have the space, create a “crib or raft” for elevating a pile of weeds (especially vines) that may re-root by piling sticks over each other in a tight grid pattern until you have a platform about a foot off of the ground.
This will prevent contact with soil while the stems and roots dry out and decompose. Here is a video on how to construct one of these piles from sticks collected nearby, as well as demonstrating some ivy removal technique. This could be done with different materials depending what you have available, like pallets or scrap lumber.
Pile weeds on a tarp temporarily and allow them to dry out. Make sure all plant parts are contained on the tarp and that there are no holes. It is possible for weeds to grow through tarps, so be sure to monitor it and only pile as much as you will be able to remove later. Covering the pile with another tarp keeps light out and helps the plants dry out while we’re still getting spring rains.
Some weeds can get chopped up or chipped into small pieces and left onsite. Himalayan blackberry is one example, as well as many woody species. This is NOT recommended for English holly, English or cherry laurel or black locust. Ideally, do this before plants produce flowers and seeds.
Consider the size of the infestation you have and a longer-term management plan. If you don’t think you will be able to dispose of all the plant material you remove, you may want to focus on a smaller portion of the infestation this year, and plan to do more next year. For example, if you can only fit half of a patch of yellow flag iris on your only tarp, focus on cutting the flower heads from the other half this year and try to dig out the rest next year.
Here are specific suggestions for some noxious and invasive weeds that people may be working with right now.
Yellow archangel and Bishop’s weed: Small fragments of these weeds will regrow new plants, so these should either go into the garbage or be piled on an elevated crib or tarp to prevent soil contact.
Bindweed and bittersweet nightshade: These should be piled on an elevated crib or tarp to prevent the vines from putting out new roots.
Himalayan blackberry and evergreen blackberry: These species can be chopped up into 2 inch pieces or smaller after being dug out of the ground and left onsite to decompose.
Bull thistle and teasel: Rosettes that have overwintered can be dug up and left onsite to decompose.
Poison hemlock: Use gloves since this plant is very toxic; dig out the taproot and bag up the plants to go in the garbage. Large amounts can be bagged to wait to get thrown out later, or piled on a tarp and covered. Don’t burn this plant because the smoke can cause poisoning and respiratory irritation, and do not compost.
Tansy ragwort: Rosettes can be dug up and put in the garbage. Tansy ragwort is toxic and is more likely to be eaten by animals as it dries out and decomposes. Large amounts can be bagged to wait to get thrown out later, or pile it on a tarp and cover. Burning is discouraged as the smoke can cause respiratory irritation, and do not compost.
Creeping buttercup: Dig up entire root system and pile up plants on elevated or dry area to let them decompose. Don’t put in backyard compost because it will spread that way. Can also put in yard waste bins if you have access to them.
Old Man’s Beard and English ivy: Cut vines growing vertically and dig up roots. The upper vines will die. Pile the pulled material on an elevated crib or tarp because it can re-root if left on the soil. Small amounts can go in yard waste bins, but do not put in your backyard compost.
English holly: If you can pull or dig small plants out of the ground, these weedy trees should be placed on an elevated pile because they can sprout adventitious roots from branches if left in contact with the soil.
Scotch broom and butterfly bush: Leave onsite whole to decompose or put these through a chipper. Make sure there are no seeds on the plants and try to get to them before they produce flowers. Scotch broom can be flammable so don’t leave large piles near structures or wooded areas. Butterfly bush branches can form new roots so monitor for regrowth, make sure it’s left on dry ground or elevated, or better yet chip it up!
Italian arum: Use gloves because the plant can cause skin irritation. Bag all plant parts and put in the garbage or let the garbage bags wait to get thrown out later. Large amounts can get piled on a tarp to be thrown out later.
Knotweed species: If you have a small number of plants that you are able dig the entire amount up, all plant parts need to go into the garbage because small fragments of the cane and the roots will regrow. If there is too much to dig up and dispose of, then the best strategy is to leave it in the ground and either cover it for a few years or use an herbicide treatment in the summer or early fall. You can harvest the new shoots right now and eat them, however.
Yellow flag iris: The entire root mass should go into the garbage or yard waste along with flowers and seed heads. Large amounts can get piled on a tarp and left to dry out. Once you can be sure it is completely dried out, plant material can be left in a dry upland area to decompose.
If you are able to take weeds to the transfer station, most can go in with the yard waste. But for regulated and toxic weeds like poison-hemlock and tansy ragwort, these should go in with the regular trash. Contact the noxious weed program to request a free voucher good for weed disposal at any King County transfer station. Visit kingcounty.gov/checktheline for station information and to gauge how busy each station may be using the web camera feeds and wait times.
Please contact our program with specific questions, visit our website for noxious weed control information and visit our blog post from a few years ago for more information about weed disposal
Follow these tips, and soon you’ll be proud to say: