In July, we introduced you to poison hemlock and deadly nightshade — two of the more common toxic weeds found in our yards more and more frequently. This month, we focus on creeping buttercup, English ivy and large (hybrid) bindweed. These noxious weeds may seem more benign in comparison, but don’t let their charming looks deceive you. These little beauties pack a powerful punch when it comes to being aggressively invasive.
CREEPING BUTTERCUP
Creeping buttercup (Ranunculus repensis) grows in almost any condition and can make livestock extremely ill within hours of ingestion, resulting in death in some cases.
This is a perennial so it survives year after year, coming back from the same rootstock. It spreads by runners or stolons (think of strawberries) and also produces seeds. It will quickly take over a field on which animals are grazing, leaving them with nothing to eat. Luckily, once the green leaves are dry its toxicity is highly reduced. However, the seeds will remain viable and can be transmitted to uncontaminated fields in harvested materials.
Creeping buttercup will thrive in areas of your lawn that are struggling and will eventually suffocate it.
How do you get rid of it?
In small areas buttercup can be pulled; remove as much of the roots as possible.
You can cover it with four to five layers of cardboard. It may take five to eight months for it to die back entirely and you should monitor for resprouting.
You can spray with herbicides but follow instructions carefully and do not use them if you are anywhere near water.
After the buttercup has been removed, amend your lawn with quality topsoil and reseed. Now is an excellent time to do this, as fall rains will help give your lawn a good start going into winter.
ENGLISH IVY, BINDWEED
To prevent your trees and shrubbery from being killed by English ivy (Hedera helix) or large (hybrid) bindweed (Calystegia x lucana), it is best to remove all vining plant material, including roots.
If you can’t dig out the roots, cutting it to the ground and immediately treating the cut ends with undiluted herbicide will help prevent resprouting. At a minimum, cutting off the vines under your bushes and or “girdling” them as they are growing up into trees (sometimes completely encircling them) will help get ahead of their growth.
You will need to continue to patrol and cut plant material regularly whenever you see new growth. This may seem tedious, but you will eventually cut enough material off the roots that they will no longer have enough stored energy to sprout new vines.
If you don’t remove ivy and/or large (hybrid) bindweed, your trees and bushes will be entirely covered. Your plants will no longer be able to metabolize energy from the sun, and they will die.
Bindweed is more likely to be found in backyards and sunny places. This time of year it’s easy to identify it by its trumpet-shaped flowers. Its softer stems are easy to remove. It does die back for the winter. Which is not to say we have “won the battle.” Next spring it will be back in full force. Consistent removal is the answer.
English ivy removal offers a significantly greater challenge. You will need to use pruning shears to cut the stems and in some cases a Sawzall. It takes longer for ivy to kill a tree as it clings to the main trunk and then slowly extends its vines out to cover the branches.
The slow process lulls us into thinking that the tree being killed is OK. This is what we are seeing in our parks, greenspaces and national forests. Sadly, ivy infestation has become epidemic.
The Washington State Weed Control Board offers a guideline to noxious weed identification and removal at nwcb.wa.gov/control-and-disposal.
The Whatcom County Weed List will help you find noxious weeds by their common names at whatcomcounty.us/923/Weeds.
Kelle Rankin-Sunter is founder of Blaine CORE, which holds free home and gardening classes at Blaine Public Library. Rankin-Sunter can be reached at fruit@Blaine-CORE.com.
