A number of the community gardens in Woodlawn are having problems with bindweed. No easy solution known. Here is some getting started information.
– weedy vine, twines around flowers, bushes, veggie plants, fences, etc.
– arrow-shaped leaves, morning glory like flowers
– leaves: 2-5 inches on mature plant, but smaller on new vine
– deep roots (10′ to 20′ deep), rhizome parts can vegatatively regrow, long lasting seeds
– recommendation is persistent detection and removal
– can take five years to remove
– two species: Field bindweed, Convolvulus arvensis and Hedge bindweed, Calystegia sepium
There are various commercial and DIY herbicides that claim to be organic. One approach here is to NOT try to pull out the plants, but instead use an organic herbicide.
– “Using a non-selective weed killer such as glyphosate (tm Roundup) would be a good option but would need repeated applications when the plant is in flower.”
– … smother them out by excluding sunlight. So something like black plastic of landscape fabric can be placed on the area, being sure to cover all the edges so any bit of light is excluded. Again, this is a multi-year battle.
2 inch root fragment can regenerate.
Washington State Univ
Seeds can lie dormant in soil for 50 years.
The root system is deep, growing as deep as 27 feet, so pulling or hoeing the weed is ineffective. According to one study, it required 13 years to eliminate bindweed using this method; any shoots that are missed will continue to nourish the vast root system.
Avoid using [glysophate] when the field bindweed needs water, because when plants are drought-stressed they slow down all internal activity, thus slowing transport of the systemic herbicides to the roots.
Mulching can sometimes be effective, but must be done with materials which bindweed can not penetrate, such as fabric weed barriers. The entire area infested must be covered for a minimum of one entire growing season, or longer. When fabric weed mats are used, the entire area should be mulched to eliminate shoots that emerge around the edges of between strips of mat, allowing the plants to survive. Horizontal roots can extend for many feet. Plastic mulches do not work because the weed can penetrate them.
I can say from personal experience that mulching (denying light) does not work. I have a bed that I sprayed, sheet mulched with cardboard, then mulched with easily 6-8″ of wood mulch. Within 2 seasons, the roots have moved up towards the surface and sprouted in multiple areas. … Some articles report pulling the shoots is effective, while others dismiss this technique.