- Author: Belinda J. Messenger-Sikes
The best way to avoid exposure to poison oak is knowing how to identify it. While the classic adage “leaves of three, let them be” can help differentiate poison oak from true oaks, it's not always correct. Poison oak is also deciduous so detecting it in the winter or spring when there are no leaves can be tricky.
More information on about this plant can be found in the recently updated
- Author: Elaine Lander
Brooms are shrubs which were originally planted in California as ornamentals and for erosion control, but are now considered to be invasive weeds since they are highly competitive. They crowd out native plants and form impenetrable barriers to wildlife. There are four common species of broom in California: Scotch broom, French broom, Spanish broom and Portuguese broom.
In the newly revised Pest Notes: Brooms, UCCE advisor Scott Oneto and UC Davis weed scientists Joe DiTomaso and Guy Kyser explain the issues with planting these invasive species. The publication includes expanded sections on biology and management and updated herbicide...
Before hiking, backpacking, or camping, people are warned to avoid poison oak. But what should you do if you find it growing on property that you own or manage?
Careful removal of poison oak is essential, since many people are allergic to it and can develop skin rashes when they come in contact with it. Effective poison oak removal can be achieved through a combination of control methods. Hand pull or use a shovel or pick to remove the entire plant, including the roots. The best time to remove poison oak is early spring or late fall when soil is more likely to be moist.
When removing poison oak, wear protective clothing, including washable cotton gloves over plastic gloves. Wash all clothing thoroughly, including shoes,...
Invasive plants—plants that can disperse, establish, and spread without human assistance or disturbance—pose a serious problem in California's waterways, wildlands and rangelands. Common garden weeds, unlike invasive plants, don't generally thrive outside of cultivation.
About 1,500 non-native plant species are currently established in California, mostly in wildlands. Almost two thirds were intentionally introduced as ornamentals from the nursery industry, or for the purposes of soil stabilization, animal forage, human food, fiber or medicinal plants.
Invasive plants originally introduced as desirable ornamentals include pampasgrass, big periwinkle, and water hyacinth. Dyer's woad was once a valuable dye...
Controlling unwanted trees, shrubs, and woody perennial grasses can be difficult in landscapes, gardens, and natural areas. These troublesome woody plants often resprout after being cut back, and the resprouting shoots can outnumber the original plants. Some woody weed plants are natives but in certain settings can create fire hazards and become problematic to human health and movement.
So how can you manage plants like ivy, bamboo, and poison oak?
A new version of Pest Notes: Woody Weed Invaders, authored by UC Davis plant scientists Joseph DiTomaso and Guy Kyser, is now available online and in print. Use this guide to find answers to the...