Central Sierra
University of California
Central Sierra

El Dorado County

El Dorado County Invasive Weed Management Group


Invasive Weed Priority List - El Dorado County Invasive Weed Management Group - March 2009

Group 1 - These terrestrial species are: a) not currently found in El Dorado County, or b) documented as small, eradicable populations, or c) deemed controllable along a defined eastern leading edge to prevent spread into the Sierra Nevada Mountains. Encourage active control/eradication efforts and education in El Dorado County.

  • Yellow starthistle (Centaurea solstitialis); eradicate at 3500 ft. elevation and higher
  • Spotted knapweed (Centaurea maculosa)
  • Tall whitetop/perennial pepperweed (Lepidium latifolium)
  • Dalmatian toadflax (Linaria genistifolia ssp. dalmatica)
  • Oblong spurge (Euphorbia oblongata)
  • Tamarisk/saltcedar (Tamarix spp.)
  • Scarlet wisteria/rattlebox (Sesbania punicea)
  • Purple loosestrife (Lythrum salicaria)
  • Canada thistle (Cirsium arvense)
  • Diffuse knapweed (Centaurea diffusa)
  • Rush skeletonweed - control at 3500 ft. elevation and higher (Chondrilla juncea)
  • Hoary cress (Cardaria draba)
  • Lens-podded whitetop (Cardaria chalepensis)
  • Purple starthistle (Centaurea calcitrapa L.)
  • Russian knapweed (Acroptilon repens)
  • Stinkwort (Dittrichia graveolens) - eradicate at 3500 ft. elevation and higher
  • Yellow toadflax (Linaria vulgaris)
  • Giant knotweed (Polygonum ssp.)
  • Sicilian starthistle (Centaurea sulphurea Willd.)
  • Meadow knapweed (Centaurea debeauxii ssp. thuilierii)
  • Dyer's Woad (Isatis tinctoria)
  • Tocalote/Malta thistle (Centaurea melitensis)


Group 2 -
Encourage the management/control of isolated populations of these terrestrial species to prevent further spread in El Dorado County.

  • Brooms (Scotch - Cytisus scoparius, French - Genista monspessulana and Spanish - Spartium junceum)
  • Arundo/Giant reed (Arundo donax)
  • Fennel (Foeniculum vulgare)
  • Goatgrass (Aegilops triuncaialis)


Group 3 - Other terrestrial species of concern; continue to increase public awareness and encourage control efforts on public and private lands.

  • Tree of Heaven (Ailanthus altissima)
  • Himalaya blackberry (Rubus discolor)
  • Puncture vine (Tribulus terrestris)
  • Pampasgrass (Cortaderia selloana)
  • Johnsongrass (Sorghum halepenses)
  • Yellow sweetclover (Melilotus officinalis (L.) Lam.
  • White sweetclover (Melilotus alba Medic.)
  • Medusahead (Taeniatherum caput-medusae)
  • Italian thistle (Carduus pycnocephalus)
  • Hedge parsley/Beggar's lice/Velcro stickers (Torilis arvensis)
  • Bull thistle (Cirsium vulgare)
  • Klamathweed (Hypericum perforatum)
  • Yellow starthistle (Centaurea solstitialis); encourage control below 3500 ft. elevation
  • Big Periwinkle (Vinca major)
  • Cheatgrass, Downy brome (Bromus diandrus)
  • Gorse (Ulex europaeus L.)


Watch List - These terrestrial species are under consideration to be added to the Invasive Weed Priority List; more information is needed to evaluate their invasive characteristics and/or ability to growing in western El Dorado County.

  • Rose campion (Lychnis coronaria)
  • Tree tobacco (Nicotiana glauca)

Aquatic weeds to watch for:

  • Hydrilla (Hydrilla veticillata)
  • Sponge plant/smooth frogbit (Limnobium laevigatum)
  • Eurasian watermilfoil (Myriophyllum spicatum)

Invasive Weeds - Group 1

C051-16
Stinkwort Seeds

Invasive Weeds - Group 2

C012-05
Fennel Flowering Umbel

Invasive Weeds - Group 3

I-CO-MLYP-CD.002
Puncturevine plants damaged by the stem weevil, Microlarinus lypriformis.

Invasive Weeds - Watch List

C244-06
Tree Tobacco Plant
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