Invasive Weed Watch

Centaurea maculosa

What are Noxious and Invasive Weeds?

What is a noxious weed?

The term "weed" means different things to different people.  In the broadest sense, it is any plant growing where it is not wanted. Weeds can be native or non-native, invasive or non invasive, and noxious or not noxious. Legally, a noxious weed is any plant designated by a Federal, State or county government as injurious to public health, agriculture, recreation, wildlife or property. (Sheley, Petroff, and Borman,1999) A noxious weed is also commonly defined as a plant that grows out of place and is "competitive, persistent, and pernicious." (James, et al, 1991).

 

Are invasive plants the same as noxious weeds?

Not necessarily, although many noxious weeds are invasive. Invasive plants include not only noxious weeds, but also other plants that are not native to this country or to the area where they are growing. The BLM considers plants invasive if they have been introduced into an environment where they did not evolve. As a result, they usually have no natural enemies to limit their reproduction and spread (Westbrooks, 1998).  Some invasive plants can produce significant changes to vegetation, composition, structure, or ecosystem function. (Cronk and Fuller, 1995).

Invasive Weed Watch

 

Common Name

Scientific Name

Rating*

Volutaria

Volutaria sp.

A

Spotted knapweed

Centaurea stoebe ssp.

Micranthos

A

Artichoke thistle

Cynara cardunculus

B

Barbed goat grass

Aegilops triuncialis

B

Bridal broom

Retama monosperma

B

Canary Island St. John's wort

Hypericum canariense

B

Carnation Spurge

Euphorbia terracina

B

Giant reed

Arundo donax

B

Pampas grass (and jubata)

Cortaderia selloana and

jubata

B

Perennial pepperweed

Lepidium latifolium

B

Purple loosestrife

Lythrum salicaria

B

Purple star thistle

Centaurea calcitrapa

B

French broom

Genista monspessulana

C

Medusahead

Elymus caput-medusae

C

Scotch Broom

Cytisus scoparius

C

Spanish broom

Spartium junceum

C

Yellow star thistle

Centaurea solstitialis

C

Yellow flag iris

Iris pseudacorus

Q

Crown daisy

Glebionis coronaria

N/I**

Devil's thorn

Emex spinosa

N/I**

Eupatory

Ageratina adenophora

N/I**

Fennel

Foeniculum vulgare

N/I**

Globe chamomile

Oncosiphon piluliferum

N/I**

Long-flowered veldt grass

Ehrharta longiflora

N/I**

Milk Thistle

Silybum marianum

N/I**

Pacific bent grass

Agrostis avenacea

N/I**

Perennial veldt grass

Ehrharta calycina

N/I**

Purple false brome

Brachypodium distachyon

N/I**

Stinkwort

Dittrichia graveolens

N/I**

Ward's weed

Carrichtera annua

N/I**