- Author: Mackenzie Patton
- Posted by: Gale Perez
The Invasive Pest Spotlight focuses on relevant or emerging invasive species in California. In this issue we are covering brooms, a group of invasive shrubs.
Invasive Broom facts
Brooms are upright shrubs in the legume family that typically produce small, yellow, pea-shaped flowers. Shrubs range from 3 to 10 feet tall. They produce flowers from mid spring to summer and produce seed pods in late summer. All brooms are prolific seed producers, with a single shrub producing as many as 2,000 to 3,500 pods containing up to 20,000 seeds.
While brooms are attractive plants, they grow in dense stands that outcompete many native plants....
- Author: Guy B Kyser
Silverleaf nightshade (Solanum elaeagnifolium) is a perennial subshrub native to the American Southwest, southern states, Mexico, and South America. It's a member of the Solanaceae, thus a relative of tomatoes, potatoes, tomatillos, eggplant, and tobacco, as well as weeds such as tree tobacco, black nightshade, and hairy nightshade.
The photo below shows silverleaf nightshade spreading in a recently disked field near UC Davis. Note that it's pretty much the only plant present: it can regrow from small rhizome fragments, and is very tolerant of hot and dry conditions. It's also poisonous to livestock. It is a listed noxious weed in many states and in a number of Mediterranean-climate countries...
- Posted by: Guy B Kyser
From New York Times, 3 October 2020 - A sad story about a poisonous invasive weed.
- Author: Angelica Reddy
- Posted by: Guy B Kyser
Exotic water primroses (Ludwigia spp.) are aggressive invaders in both aquatic and riparian ecosystems. The plants form dense mats over the water surface. These mats constrain navigation and interfere with recreational activities, irrigation, drainage, and agricultural production. Rapid growth of these weeds also displace native plants and wildlife in aquatic ecosystems.
In the US, several exotic Ludwigia taxa have naturalized and become invasive: Ludwigia hexapetala, L. peploides subsp. peploides, L. peploides subsp. montevidensis, and L. grandiflora. Stakeholders are eager to get these weeds under control by all means necessary and one option is...
- Author: Christy Morgan
- Posted by: Guy B Kyser
South American spongeplant (Limnobium laevigatum) is a free-floating, freshwater aquatic plant that has been introduced to the Sacramento-San Joaquin Delta. Spongeplant can propagate sexually through seed production and asexually through the development of stolons that produce new plants. This vegetative growth results in floating mats of plants that can fragment and spread with the water current.
Between August 2017 and March 2018, two studies were completed to determine the growth potential of South American spongeplant at different temperatures. These studies were designed to investigate how changes in the Delta's water temperature may affect the species' ability to proliferate and spread.
Plants were...