What is an “invasive species”?

“Invasive species are organisms (plants, animals, or microbes) that are not native to an environment, and once introduced, they establish, quickly reproduce and spread, and cause harm to the environment, economy, or human health.” (California Department of Fish & Wildlife, https://www.wildlife.ca.gov/Conservation/Invasives/About)

Why are invasive plants a problem?

As stated in the Master Plan for the Claremont Hills Wilderness Park, “Invasive plant species degrade native habitat and displace native plants and wildlife, increase wildfire potential; increase slope erosion potential; and degrade recreational opportunities. Therefore, invasive plant species control and management are important components to preserving the integrity of CHWP’s native habitat.” (Claremont Hills Wilderness Park Master Plan, p 3-19, http://www.ci.claremont.ca.us/government/departments-divisions/human-services/parks/claremont-hills-wilderness-park-chwp/chwp-master-plan).

What invasive plants are present in the Wilderness Park?

Here are the invasive plants that have been observed or reported to date. After each name is a link that species’ Calflora page, which has photos, a map of statewide observations, bloom time, and lots of other useful information.

Cootramundra Wattle (Acacia baileyana) [Calflora]
Longleaf Wattle (Acacia longifolia) [Calflora]
Black Wattle (Acacia mearnsii) [Calflora]
Tree of Heaven (Ailanthus altissima) [Calflora]
Beefwood (Casuarina sp.) [Calflora]
River Redgum (Eucalyptus camaldulensis) [Calflora]
Tasmanian Blue Gum (Eucalyptus globulus) [Calflora]
Forest Red Gum (Eucalyptus tereticornis) [Calflora]
Edible Fig (Ficus carica) [Calflora]
Tree Tobacco (Nicotiana glauca) [Calflora]
Olive (Olea europaea) [Calflora]
Jerusalem Thorn (Parkinsonia aculeata) [Calflora]
Black Locust (Robinia pseudoacacia) [Calflora]
Peruvian Pepper Tree (Schinus molle) [Calflora]
Salt Cedar (Tamarix ramosissima) [Calflora]
Mexican Fan Palm (Washingtonia robusta) [Calflora]

Castor Bean (Ricinus communis) [Calflora]
Silver Senna (Senna artemisioides) [Calflora]
Spanish Broom (Spartium junceum) [Calflora]

Mediterranean Cabbage (Brassica fruticulosa) [Calflora]
Black Mustard (Brassica nigra) [Calflora]
Field mustard (Brassica rapa) [Calflora]
Sahara Mustard (Brassica tournefortii) [Calflora]
Short-pod Mustard (Hirschfeldia incana) [Calflora]
London Rocket (Sisymbrium irio) [Calflora]
Hedge Mustard (Sisymbrium officinale) [Calflora]
Indian Hedge-Mustard (Sisymbrium orientale) [Calflora]

Italian Thistle (Carduus pycnocephalus) [Calflora]
Tocalote (Centaurea melitensis) [Calflora]
Yellow Star-Thistle (Centaurea solstitialis) [Calflora]
Bull Thistle (Cirsium vulgare) [Calflora]
Milk Thistle (Silybum marianum) [Calflora]
Russian Thistle (Salsola tragus) [Calflora]

Ground Covers, Vines, or other Forbs:
Eupatory, Croftonweed (Ageratina adenophora) [Calflora]
Cape-Ivy (Delairea odorata) [Calflora]
Fennel (Foeniculum vulgare) [Calflora]
Gazania (Gazania linearis) [Calflora]
Algerian Ivy (Hedera canariensis) [Calflora]
Smooth Cat’s-Ear (Hypochaeris glabra) [Calflora]
Horehound (Marrubium vulgare) [Calflora]
Oxalis pes-caprae (Bermuda buttercup) [Calflora]
English Plantain (Plantago lanceolata) [Calflora]
Curly Dock (Rumex crispus) [Calflora]
Periwinkle (Vinca major) [Calflora]
Red Stemmed Filaree (Erodium cicutarium) [Calflora]
Puncture Vine (Tribulus terrestris) [Calflora]

Slender Wild Oat (Avena barbata) [Calflora]
Wild Oar (Avena fatua) [Calflora]
Annual False-Brome (Brachypodium distachyon) [Calflora]
Ripgut Brome (Bromus diandrus) [Calflora]
Soft Brome (Bromus hordeaceus) [Calflora]
Red Brome (Bromus madritensis ssp. rubens) [Calflora]
Pampasgrass (Cortaderia selloana) [Calflora]
Bermuda grass (Cynodon dactylon) [Calflora]
Italian Ryegrass (Lolium perenne) [Calflora]
Rat-tail fescue (Festuca myuros) [Calflora]
Foxtail Barley (Hordeum murinum) [Calflora]
Fountain Grass (Pennisetum setaceum) [Calflora]
Smilo Grass (Stipa miliaceum) [Calflora]

If you’ve noticed another invasive plant in the Wilderness Park or if you have a question about whether a plant is invasive, please contact us at info@friendsofthewildernesspark.org.  Please include a photo of the plant in question, if you have one.

What are the Friends doing about invasive plants?

The Friends are currently using CalFlora to map invasive plants in the Wilderness Park, creating a GIS map that shows what species and how many plants are present in a particular location.  You can see what we’ve mapped so far here:

(note that this doesn’t display well on a phone — it’s best viewed with a computer)

This map will help to develop a management strategy and can be used a baseline for monitoring control efforts and new invasions.

If you would like to help with the mapping effort, please contact us at info@friendsofthewildernesspark.org.