The green threads wrapped around this parsley are dodder (Cuscuta). It’s a parasitic plant without any leaves or roots of it’s own. It finds a living plant, wraps around it, and digs sharp spikes into the victim plant to suck the juice. Other names include devil’s guts, devil’s hair, devil’s ringlet, goldthread, hailweed, hairweed, hellbine, love vine, pull-down, strangleweed, and witch’s hair. Essentially it’s a vampire, and the dang thing’s found its way into my garden when I wasn’t looking. What’s worse, it’s flowering. I only hope to goodness I got to it before it set seed.
