Invasive Species

Noxious weed! This “cute” perennial plant grows about 3 feet tall, displaces desirable vegetation, and reduces the biodiversity of our native ecosystems. It was introduced from southern Europe as an attractive ornamental. But it has no natural deterrents, takes over natural habitats, and is quite invasive…

Puncturevine (Tribulus terrestris) is an attractive green plant with small yellow flowers commonly seen growing prostrate along the side of the road. A native to Southern Europe, it’s also referred to as “goathead.” However, underneath its foliage lies danger: spiky seedpods with needle-point spikes. If…

Yellow starthistle is a spiky, fast-growing, invasive weed in home landscapes, parks, rangelands, roadsides, and natural areas. It outcompetes other plants by growing in impenetrable stands and depleting soil moisture. It's also highly flammable which increases the risk of wildfires where it's growing. …

A few strands of thin, feathery, green plants growing under the dock didn’t catch anyone’s attention last spring. But those strands spread quickly and within months the lake’s calm waters were tangled in mats of the feathery Eurasian watermilfoil, an aggressive aquatic plant that grows quickly and clogs…

Visiting Yosemite National Park is an awe-inspiring experience, even for the most seasoned of travelers. The valleys, waterfalls, giant sequoias, and iconic Glacier Point are all bucket list destinations ideal for a family camping vacation. To continue enjoying beautiful parks like Yosemite, it is important…

Help raise awareness of invasive species by participating in the California Invasive Species Action Week (CISAW) held June 6-14, 2026! Invasive species are non-native pests that can negatively impact our waters, native ecosystems, agriculture, health, and economy. Each day during the week, UC IPM will…

Updated May 29, 2026 at 4:30pmAn invasive insect called the glassy-winged sharpshooter (GWSS) has been found on grapevine shipments sold at select Costco locations in Northern California between April 21 and May 21, 2026. Note that the timeframe for grapevine plants sold at Costco has been extended to April…

Looking to keep your brain stimulated this summer? Need information about garden pests? Join us every third Thursday of the month from 12:00 to 1:00pm PST to learn about a wide range of urban pest management topics. This series is free and open to the public, but advance registration is …