Idaho Native Bitterbrush (Purshia tridentata)

Bitterbrush (Purshia tridentata (Pursh) DC), commonly called antelope bitterbrush, is a native shrub species found throughout much of the Intermountain West and is well established across Idaho. This plant belongs to the rose family (Rosaceae) and is an important component of Idaho’s native plant communities. Bitterbrush is well adapted to dry, semi-arid environments and plays a critical ecological role in sagebrush steppe, a dry grassland ecosystem with low rainfall, and open woodland ecosystems across the state.

Purshia tridentata is native to Idaho and occurs widely, particularly in southern and central regions. It grows on well drained, rocky or gravelly soils and is commonly found on slopes, benches, and open flats. Bitterbrush often grows alongside Bluebunch wheatgrass, Idaho fescue, sagebrush, juniper, and ponderosa pine. Its widespread distribution confirms that it is a naturally occurring species rather than an introduced plant.

Bitterbrush is a woody, multi stemmed shrub that can reach heights of up to ten feet. Its wedge-shaped leaves have three small teeth at the tip, which gives the species its name tridentata. In spring, it produces small yellow to cream colored flowers that attract native pollinators. Seeds are often cached by rodents, supporting natural regeneration.

Ecologically, bitterbrush provides critical benefits for wildlife. It is a primary winter food source for mule deer, elk, and pronghorn because it remains accessible and nutritious when other vegetation is limited. It also provides cover for birds and small mammals and improves soil fertility through nitrogen fixation.

In Idaho, bitterbrush is commonly used in rangeland restorationand habitat improvement. However, it is sensitive to overgrazing, frequent fire, and poor regeneration. Maintaining healthy populations is essential for sustaining biodiversity and ecosystem resilience across Idaho’s rangelands. A University of Idaho bulletin describing sagebrush grass habitat types in southern Idaho identifies antelope bitterbrush (Purshia tridentata) as a characteristic shrub in multiple shrub grass communities, reinforcing its native status and ecological importance in Idaho rangelands.

References

Utah Valley University. (n.d.). Purshia tridentata – Antelope bitterbrush. https://www.uvu.edu/crfs/native-plants/purshia-tridentata.html

Eastern Washington University. (2019). Purshia tridentata – Flora of Eastern Washington and adjacent Idaho. https://inside.ewu.pedu/ewflora/purshia-tridentata/

Hironaka, M., Fosberg, M. A., & Winward, A. H. (1983). Sagebrush-grass habitat types of southern Idaho (Bulletin No. 35). University of Idaho, Forest, Wildlife and Range Experiment Station. https://objects.lib.uidaho.edu/fwres/fwres171.pdf

Backyard Garden Fencing

If your inner lumberjack is urging you to build that garden fence to keep wildlife and uninvited produce-pickers out, it would be wise to stop and research first. After all, fencing can be pricey and there may be regulations to follow. You might also want to determine or consider which specific herbivores are feasting and trampling, how visible your garden space is to neighbors, your budget, and any local statutes that may apply. It is also helpful to consider if your neighborhood critters are jumpers, climbers, or diggers. After review, many gardeners realize that they only need winter protection for young fruit trees. It’s worth doing your homework before building that fence.

Fencing Regulations
An understanding of fencing requirements, materials, pricing, purpose, and aesthetics varies with your city, state, and neighborhood. Check your plot map and local regulations; state, county, and municipality. In Idaho, Title 35 addresses building and removing fences and the rights and responsibilities of landowners. Idaho Code 35-101 defines a lawful fence must not be less than 4.5 feet high, and the bottom board, rail, pole, or wire must not be more than twenty inches above the ground. City and town fencing rules are usually found under building and permits, including property easements. Neighborhood HOAs will likely provide additional, detailed requirements and responsibilities.

Consider Local Wildlife
Wildlife in the garden may be more than a neighbor’s pet. In a more open field area, it might be deer, rabbits, raccoons, and/or voles. Your list of pests may also include birds.

Fence Design Considerations
The design must provide sufficient available light for your plants’ needs. Soil type matters too, especially if it’s clay. When clay is wet, fence posts wobble unless secured 2-3 feet deep in a concrete base.

Fence Height
The fence height varies based on which wildlife are most troublesome. Build a 2-3 foot high fence for cats, dogs, and rabbits to block their entry. If raccoons, opossums, voles, or squirrels are a problem, then an underground barrier is needed (usually chicken wire). These animals can also climb, thus leaving the top 18 inches of chicken wire loose will discourage these critters as the fencing will bow down when they try to climb. You could also try an electric wire along the top. If you need to inhibit larger animals, such as deer, then the fence height must be
6-8 feet. For troublesome birds, low visibility metal wires can have negative impacts if the bird collides with the wire. Avoid this by marking it with cloth strips tied to the wire. Bird netting placed over the fenced area, using PVC pipes to support, is an option that prevents flying animals’ entry. 

Fence Materials
Materials can include poultry fencing, chain link, wood, woven wire, and more. Wood choices are varied, and the longest lasting are treated. This is recommended, especially for the posts. Treated wood has a life expectancy of 15-30 years depending on the type of wood you choose. Fences designed in horizontal lines will handle wind gusts more easily than a vertical design. When it comes to cost, wood, iron, and electric are more expensive than chain link, woven wire, or poultry fencing. You may be able to install a wood fence yourself. This option can also be good for a bit of privacy from passersby and neighbors. Electric fencing is

normally used to contain livestock but can be successful for pet containment and denying some animals entry. Just add some cloth flags or smooth PVC on the top wire for a visual warning to birds and humans. Barbed wire is often used in-between the top and bottom electric wires. With any of these fencing options, should you have a problem with the “diggers”, about 3 inches of buried chicken wire under the fence row should keep those critters out. Select a fencing that meets the broadest variety of possible avian and animal invaders. Of course, don’t forget to plan for at least one gate to enter the garden area.

Tree Guards
Finally, don’t forget tree guards if your fruit trees or other trees and shrubs are afflicted by girdling, fresh bud nipping, or leaf eating. Creating a physical barrier is the best overall prevention strategy. Surround the tree with a sturdy fence in the fall, after clearing mulch and grass, to prevent voles and mice. Bury the bottom of the fencing in the soil and set it to at least 18-24 inches in height above an anticipated snow line. A bit of planning and research protects your garden and wildlife for years to come.