Invasive Plants in Delaware

What is an invasive plant?

Aggressive, creates problems for native plants, animals and natural communities

Has very few, often no predators in its new location

Not native – does not naturally occur in a specific area

Where do they come from?

45o

30o

45o

30o

Grows quickly

Produces many seeds and/or spreads by underground root systems (rhizomes)

Produces biological toxins that suppress the growth of other plants

Hardy, out-competes natives

Usually non-native

Few predators

What makes a plant invasive?

How do they get here?

ornamental landscapes and gardens

conservation projects, erosion control

pallets and packing material

crop seed

Why should we be concerned?Ecological Impacts

alter soil chemistry

fire hazards

alter hydrology

changes in plant communities and biodiversity

competition with native plants

English Ivy

Hedera helix

Japanese Honeysuckle

Lonicera japonica

Photo by David Cappaert

Multiflora Rose

Rosa multiflora

Phragmites

Phragmites australis