Plant of the Month: Teasel

Jul 16

Since nursery sales are paused for the summer, we are taking a break from our native plant blog series to talk about a non-native plant: teasel (Dipsacus spp.)!

All About Teasels

Teasel’s genus name *Dipsacus* comes from the Greek for “thirst”, referring to the cup at the base of its opposite leaves.

Teasels are known for their spiky, pineapple-esque flowerheads, which are used in bouquets and dried flower arrangements. Most teasels only live for 2 years, staying as a small rosette during their first year while developing a thick taproot. In their second summer, they send up 6-foot tall flowering stalks, which bloom just once before the plant dies. Teasels love sunny, seasonally wet zones near creeks or seeps, as well as disturbed places like roadside ditches.

Native to Europe, North Africa, and Asia, teasel was introduced to North America in the 1800s. The most common species in California are wild teasel (Dipsacus fullonum) and Fuller’s teasel (Dipsacus sativus). The dried seedheads of Fuller’s teasel have stiff, gently curved spines and are traditionally used for carding or “teasing” wool. Fuller’s teasel may have been artificially selected from wild teasel, a medicinal species with soft and straight spines that are unsuitable for wool processing.

Why and How to Remove Teasel

While non-native plants like teasel do provide food for generalist pollinators like honeybees, they often do not attract the diversity of specialist insects that native plants support.

In its native range, teasel has many benefits: its role in traditional wool-making, food for insects and birds, and the ability to rapidly revegetate disturbed sites. However, here in California, this means teasel thrives after roadwork, construction, or other impacts, quickly displacing local species like narrowleaf milkweed (Asclepias fascicularis), irisleaf rush (Juncus xiphioides), sneezeweed (Helenium puberulum), mugwort (Artemisia douglasiana), and marsh baccharis (Baccharis glutinosa). These native plants are vital to Indigenous cultures and support a diversity of specialist pollinators. To ensure the continuation of California’s unique biodiversity, it is essential to manage teasel and stop the habitat degradation that enables its spread.

At Byrne Preserve, our dedicated staff and volunteers have transformed a teasel-dominated, horse-compacted floodplain into a biodiverse meadow. We manage teasel by cutting off their flowering stalks until they are exhausted and die, or by digging them up by their taproot. We then sheet mulch to suppress further germination and plant locally appropriate species. Even after mulching and planting, an ongoing effort is needed to remove resprouts and to care for the native vegetation.

*The floodplain zone at Byrne Preserve in 2015 (left) and 2019 (right)*

Get Involved

If you have teasel at home, we encourage you to pull it and install native plants. You can also document teasel populations on iNaturalist or Calflora and sign up for volunteer removal workdays! With funding from Valley Water, Grassroots Ecology staff and volunteers are actively removing a large teasel patch at Palo Alto’s Pearson-Arastradero Preserve.

In addition to restoring teasel-infested areas, we must prevent healthy habitats from being destroyed. Support the protection of intact ecosystems by Indigenous tribes and other responsible land stewards, and do not move seedheads from one place to another.

Thanks for joining us on this month’s excursion into the world of teasels. Next month, we’ll highlight one more non-native species before returning to our native plant posts in September.