It tastes great in salads, but fennel (Foeniculum vulgare) is an unfortunate weed in California. It grows avidly along roadsides and in other disturbed places. This plant grows up to ten feet tall, with feathery leaves and yellow umbrella-shaped umbels of flowers.
Fennel is an invasive species, and takes over areas by forming dense stands where nothing else can grow. This isn’t just because the plants are so numerous that there is no room for any others. They also exude chemicals that actually prevent their competitors from growing!
Check out the above video for an musical animated interpretation of why fennel is a problem…