Conservation

Invasive Species

Sesbania

Volunteers removing first year sprouts of Sesbania.

Description

Sesbania punicea (Scarlet wisteria, Chinese rattlebox, Red sesbania) is a riparian plant native to Argentina, South America. It is a woody shrub that can grow up to 15 feet tall. The plant has bright green, drooping leaflets in opposite pairs, and in the spring and summer the plant displays bright red, showy flowers that are similar to pea flowers. Throughout the summer and fall, the plant produces hundreds of seedpods that may stay on the plant through the winter.

The four-winged seedpods are six-to-eight centimeters long, hang in clusters, and mature from green to brown. Each pod contains 3-9 seeds, which create a distinct rattling sound when shaken or moved by a breeze. The pods eventually break open, releasing thousands of seeds which grow into new Sesbania plants. All parts of the plant, particularly the seeds, are poisonous to mammals, birds and reptiles.

Problems with Sesbania punicea:

Sesbania punicea forms solid stands along riverbanks, which displace native vegetation and associated wildlife, and in turn decrease the biodiversity of the riparian area. These dense stands of scarlet wisteria can decrease water flow and quality and decrease access to the river for fishing, boating and other recreational activities. The plant matures in one year and can produce thousands of seeds per year. The winged seedpods drop off of the plant into nearby water and then travel downstream to fertile ground. The seeds have a very high germination rate, so many new plants sprout annually.

Where is Sesbania punicea in the Parkway?

Sesbania punicea can be found along the river from the Highway 41 bridge downstream past the Highway 99 bridge. The large, dense areas of scarlet wisteria occur in both slow-moving water (especially gravel mining ponds and other waterways outside the main channel of the river), and along the main channel. During the summer, scarlet wisteria can easily be spotted from the Milburn Overlook, on the island near Jensen River Ranch, Moen Lakes, and at Scout Island.

What are we doing about Sesbania punicea?

Volunteers and the California Conservation Corps have contributed to removing scarlet wisteria from the Parkway on lands to which we have access. Our staff and volunteers continue to monitor sites where scarlet wisteria has previously been removed. As access to areas of scarlet wisteria infestation become available, staff and volunteers will coordinate scarlet wisteria removal days.

Staff and volunteers also work on Scarlet Wisteria removal during the River Steward workdays.

For more information, read the article "Scarlet Wisteria Alert" from the Summer 2001 Parkway Current.