Mediterranean Desert Knapweed

Volutaria tubuliflora

Big Canyon, Upper Newport Bay, Newport Beach, CA. 4-1-15. © Ron Vanderhoff

Highly invasive exotic species on the RED ALERT Emergent Invasives list
(California Native Plant Society, Orange County Chapter)

Native to southern Europe to the Arabian peninsula

Back to Asteraceae of Orange County, California
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This High Priority and Red Alert invasive weed was first discovered in the U. S. in the Anza-Borrego area in 2010. On March 31, 2015 a second colony was discovered at Big Canyon, Upper Newport Bay. The colony was subsequently surveyed, estimated at 500 to 1,000 individuals and appears to cover approximately .5 acre at the Northern edge of the canyon, adjacent to urban landscaping. Removal and management has begun and will continue for several years, until all plants are removed.

This is a very troublesome annual invasive plant that many experts believe has the potential to spread very quickly through much of California, displace native plants and greatly disrupt healthy ecosystems. Germinating with fall and winter rainfall, it grows quickly up to 1-2 meters high and begins dispersing abundant seed within only a few months. Populations can multiply exponentially from year to year.

Additional occurrences anywhere in the area or the county should be reported immediately to Ron Vanderhoff