Invasive Plants & More

Invasives 101

(Visit UNH Cooperative Extension's page for LOTS more info!)

What is an invasive plant?

• not native to a particular ecosystem,

• whose introduction does or is likely to cause economic or environmental harm or harm to human health.

• capable of moving aggressively into an area, monopolizing light, nutrients, water, and space to the detriment of native species.

Why should we care?

• Invasive plants can reduce

  • biodiversity,

  • imperil rare species,

  • reduce wildlife habitat by eliminating native foods or changing cover or nest sites,

  • degrade water quality,

  • reduce forest and farm crop production, and

  • cause human health problems.

NH Invasive Plants -- What is Prohibited?

The State of New Hampshire has 27 plant species on a prohibited list.

New Hampshire lists another 24 plant species as restricted, such as rosa rugosa!

What are the rules?

Essentially nobody is allowed to collect, import, transport, sell, propagate, transplant or cultivate any species (including all cultivars and varieties) of those species listed on the "New Hampshire Prohibited Invasive Species List"

Some tricks to identification:

• Invasive honeysuckles have a hollow stem

• Japanese knotweed has a hollow stem and zigzag stem

• Multiflora rose has a hairy stipule

• Oriental bittersweet has orange roots

• Burning bush has winged branches

• Autumn olive has leaves with silver undersides

• Dame’s rocket looks like phlox but has 4-petaled flowers (D-A-M-E) not 5 (P-H-L-O-X)

• European and Japanese barberry are both invasive

• Norway maple has white sap when leaf is broken off, 5-lobed leaves, and a horizontal samara

Adapted from: UNH Cooperative System, Invasive Plants