“Can you tell me what this is and how to kill it? I thought I dug it out already, but it keeps coming back. Its roots run really deep.” -Question from Natalie of Oregon
ANSWER: Sadly, your garden has a field bindweed (Convolvulus arvensis) infestation. This is one of the most notoriously difficult perennial weeds to remove. The vine tightly twines up anything, producing little white flowers that look like tiny morning glories and produce lots of seeds.
Its fast-spreading white-rooted runners spread deep and wide, making them a challenge to dig and collect, especially when they become intertwined with the roots of your shrubs and perennials. Here is the three-stage approach I take to kill it. (BTY, weed killers won’t touch this weed, so put them away!)
- Dig out as much of the root system as possible, and remove any vining stems that may have seed developing. When digging white underground runners, gently loosen the soil around each with a trowel, following each until it is fully removed. If you keep even a small piece in the ground, it will re-root and grow. This can be a challenge when working around your garden plants, but be diligent. In some cases, you may have to dig up perennials, remove the bindweed roots from their base, and replant them. Keep watch for any new bindweed shoots that appear and dig them out immediately.
- To keep underground stems from returning in really infested areas, cover the area with mulch cloth and mulch it over. After a season, all parts should be smothered, and you can pull up the mulch cloth and resume gardening as usual.
- Keep an eye out for nearby bindweed outside of your yard, and at best try to keep it from flowering and moving back into your yard. Talk to your neighbors, if need be.