Register Today!

Learn about updated guidelines and how they affect your industry in a 90 minute workshop. learn more »

Register as an early bird today!

Join Dr. Daniel Simberloff & Dr. Anthony Ricciardi in Kamloops. Register by April 15th for early bird pricing! learn more »

Parrot's Feather

A popular aquatic garden plant that spreads with water currents, animals, boats/trailers and fishing gear. Dense stands can stagnate water, and increase breeding grounds for mosquitoes

Zebra/Quagga Mussels

These tiny freshwater mussels clog drains, damage infrastructure, and are very costly to control/eradicate learn more »

Giant Hogweed

A towering toxic invasive plant with WorkSafe BC regulations learn more »

Invasive Species Research Conference

Turning Science into Action! Co-hosted by Thompson Rivers University and the Invasive Species Council of BC. learn more »

European Fire Ant

A tiny ant with a toxic sting learn more »

Purple Loosestrife

An aggressive wetland invader that threatens plant and animal diversity learn more »

Orange Hawkweed

Also yellow, these invasive plants replace native vegetation along roadsides, and threaten areas not yet reforested learn more »

Japanese Knotweed

Grows aggressively through concrete, impacting roads and house foundations learn more »

Spotted Knapweed

A single plant spreads rapidly with up to 140,000 seeds per square metre learn more »

Scotch Broom

An evergreen shrub that invades rangelands, replaces forage plants, causes allergies in people, and is a serious competitor to conifer seedlings learn more »

St. John’s Wort

Species
Hypericum perforatum

St. John's-wort (Hypericum perforatum) is a perennial invader of grazed and disturbed lands that creates dense stands, displacing native plant species and reducing available forage for livestock and wildlfie. Plants contain a toxin that causes skin irritation and blistering in light-coloured livestock when exposed to the sun. 

Mature plants grow up to 1 m high and turn a rusty red, prefering dry sandy soils and full sun. It can be found at low- to mid-elevation areas of the coast, grasslands, and forest regions of BC, namely the Kootenays, Okanagan, Boundary, North Thompson, Cariboo, Skeena, Fraser Valley and Vancouver Island. 

St. John's-wort spreads aggressively by a lateral-reaching root system that can form new buds that are separate from the parent plant. Seeds also have a gelatinous coating that aids long-distance dispersal and can survive in the soil for 10 years. One plant can produce over 100,000 seeds per year, spreading by wind and water.

The flowers of this herb have bright yellow petals with black dots that are produced in clusters at the tips of the branches. There can be 25-100 flowers per cluster. The fruit is a capsule with many small, brown to black cylindrical seeds. Stems are often winged with simple veined, opposite leaves.

Gallery: St. John’s Wort