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Saturday - March 21, 2009

From: Parker, CO
Region: Rocky Mountain
Topic: Trees
Title: Trees for Parker, Colorado that will not harm horses
Answered by: Nan Hampton


we are searching for trees that will grow well in Parker Colorado and not be poisonous to our horses


The following trees grow in or adjacent to Douglas County, Colorado:

Betula occidentalis (water birch)

Cornus sericea ssp. sericea (redosier dogwood)

Fraxinus pennsylvanica (green ash)

Juniperus scopulorum (Rocky Mountain juniper)

Pinus contorta (lodgepole pine)

Pinus flexilis (limber pine)

Populus angustifolia (narrowleaf cottonwood)

None of them appear in my favorite Toxic Plant databases (Poisonous Plants of North Carolina, Cornell University Plants Poisonous to Livestock, Canadian Poisonous Plants Information System, University of Pennsylvania Poisonous Plants, or Texas Toxic Plant Database.

The Cornus sericea ssp. sericea (redosier dogwood) and the Fraxinus pennsylvanica (green ash) do both occur in the University of California-Davis Toxic Plants) database as possibly causing dermatitis in humans and Juniperus sp. is listed as being a gastrointestinal irritant of mild toxicity if the berries are eaten in large quantities.

Please note that Pinus ponderosa (ponderosa pine) is toxic to livestock, including horses.  If you decide to include pine trees, be sure it is one of the other species named above, not ponderosa pine.

You can see more choices if you go to our Recommended Species page and choose 'Colorado' from the map or pulldown menu.  You can then NARROW YOUR SEARCH by selecting 'Trees' under the Habit (general appearance) option.  If you see another tree that you like, you can check its possible toxicity against the databases above. 

Also, here are several databases that list plants, native and otherwise, that should NOT be included in areas with horses: 

10 Most Poisonous Plants for Horses from EquiSearch.com

Poisonous Plants from Trailblazer Magazine

Toxic Plants:  Horses from the ASPCA

Horse Nutrition:  Poisonous Plants from Ohio State University

You might also like to read Bulletin 415-Plants Poisonous to Livestock in the Western States from the USDA Agricultural Research Service. 

Betula occidentalis

Cornus sericea ssp. sericea

Fraxinus pennsylvanica

Juniperus scopulorum

Pinus contorta

Pinus flexilis

Populus angustifolia




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