Common Name: German Ivy or Cape Ivy
Scientific Name: Delairea odorata
Code: DEOD
Group: Dicot
Family: Asteraceae
Growth Habit: Forb/Herb Subshrub Vine
Duration: Perennial

What does it look like?

Cape ivy is a perennial vine with shiny, bright green, shiny, star-shared leaves with 5 to 6 lobes. They alternate on the sides of the stem but are arranged singly and vary in size. There are two tiny stipules at the base of each leaf that are cup-like and shaped like ears. The flowers are arranged in groups of twenty or more and have dime-sized discoids and give off an unpleasant scent (Bossard et al. 2000).

The flowers of Cape ivy produce tiny seeds with a crown of hairs that drops off when the seed detaches. Hard frost stimulates seed set and studies have shown poor germination rates in California. However, once Cape ivy establishes itself it can also spread through vegetative rooting. It is also frost sensitive, so hard frosts knock it back.

Where does it grow?

Over 500,000 acres are infested with Cape Ivy in California, from Del Norte County to San Diego. It prefers sites with year-round moisture and that are shady with some history of disturbances, including stream banks, coastal forests or soils with a high water table.

Cape Ivy can also grow in grasslands, open oak forests, coastal scrublands, pine forests, and other areas without year-round moisture. In these cases, the vines tend to die back in the dry season and grow rapidly during the wet season (Bossard 2000). Cape Ivy is native to moist mountain forests of South Africa. By the 1960s it had naturalized throughout California’s coastal riparian areas.

Is it in our watershed?

Currently this species has not been observed within the Mattole watershed but it is important to raise community awareness. If Cape Ivy is spotted in this area, it needs to be reported and eradicated immediately.

Why is it a problem?

Cape ivy has the ability to grow over most vegetation, especially trees, and form a solid cover that blocks out light and smothers other plants. It also has a tendency to grow in thick masses up the trunks of trees and along branches, causing branches to break and trees to fall in many cases. Infestations of Cape ivy can reduce native plant diversity by as much as 50 percent in many areas, often leading to monospecific habitats (Bossard et al. 2000).

How do you get rid of it?

Manual Removal: When removing this species, it is important to remove the ENTIRE plant, including the roots, because if any fragments are dropped or left behind they will resprout. In riparian areas it is important to begin removal projects at the headwaters and then move down because fragments of cape ivy that drift downstream during floods can reinfest areas where they are deposited.

Mechanical Removal: It is important to clear away all native and invasive vegetation to gain access to the root system of the Cape Ivy. Then, pull roots and stems after loosening the soil with a three-pronged mini-rake (Bossard, 2000). In areas where Cape Ivy grows in mat-like infestations on the ground, it is possible to roll up the entire infestation like a carpet using a potato hoe or a rake (Archbald 1995 in Bossard 2000). Immediately following removal, cape ivy should be placed on or in plastic bags and should NOT come in contact with the ground. Soda lime will help ivy breakdown in the plastic bags (Bossard, 2000).

Sites require monitoring every two months for the first year and every four months the second year to locate and kill resprouts. Examine sites each year, after the second year, to monitor for and control resprouts.

Prescribed Burns: A post-removal burning should occur when the plants are dry. After this, monitor removal sites each month and remove and burn all resprouts (NPS, 2001).

Biological Control: Two South African insects are possible biological control agents: the Cape Ivy gall fly, Parafreutreta regalis, and a tiny moth, Acrolepia sp.

Author:
Unity Peterson, Invasive Plant Program Coordinator, Mattole Restoration Council, Petrolia, CA.

Photographs:
Tony Morosco, 2002

References:
Bossard, CC., J.M. Randall and M. Hoshovsky. (eds.) 2000. Invasive Plants of California’s Wildlands. University of California Press, Berkeley, CA. Online version: http://groups.ucanr.org/ceppc/Invasive_Plants_of_California's_Wildlands/

NPS 2001. Exotic Plant Species List. Scientific and Common Names of known Exotic Plant Species in the Redwood National and State Parks. National Park Service. http://www.nps.gov/redw/epsplist.htm