Invasive Species

Invasive Species at Buford Park

Invasive weeds are the largest single issue challenging the integrity of native ecosystems on Mt.Pisgah (Lane County Parks’ Howard Buford Recreation Area). The rare and valuable prairie, oak savanna and woodland habitats which dominate Mt. Pisgah are among the largest native dominated remnants in the Willamette Valley. A planned park-wide Habitat Management Plan should eventually address how to manage invasive species. This page describes some of the most problematic weeds that can displace native plant communities and wildlife that depend on them.

If you’d like to help protect rare habitats on Mt. Pisgah, please contact our Volunteer Coordinator.

A Rogue’s Gallery of Invasive Weeds

False Brome (Brachypodium sylvaticum)

This lovely, hairy grass stays bright green late into the fall. Unfortunately, it forms dense monocrops that replace diverse native understory plant communities in large areas of forest and woodland,especially in rare oak habitats. Although it prefers shady areas, it also is known to eventually spread into open meadow habitats. Currently, false brome is a great threat to native habitats on Mt. Pisgah, and it is exploding across western Oregon. At this time, control methods are experimental.

Shining Geranium (Geranium lucidum)

Like false brome, this low-growing species forms extensive, pure stands in shady areas. Few native wildflowers and grasses seem to be able to grow in its presence once it moves in. Because it is a new arrival like false brome, little is known about effective control methods.

Armenian blackberry (Rubus armeniacus)

Formerly mistaken for Himalaya blackberry (Rubus discolor), this widespread, mounding vine is familiar to many people in the Willamette Valley, both for its robust invasive qualities and tasty berries in late summer. Birds eat the fruits and spread the seed. Blackberry can become established nearly anywhere, but prefers full to part sun, especially along shorelines and moist soils. As it grows, it physically overwhelms shorter vegetation. The recent introduction of a fungal disease may help in controlling this plant.

Scot’s broom (Cytisus scoparius)

Many people know this shrub as well as they know blackberry. It has bright yellow flowers in spring, and can colonize disturbed, poor soils because the bacteria that live on its roots add nitrogen to the soil. That is a good thing in the garden, but not necessarily in nature. It is very invasive in sunny habitats, such as prairies and savannas. Friends of Buford Park works to remove Scot’s broom from meadows on Mt. Pisgah that serve as nesting habitat for Western Pond Turtle.

Reed canarygrass (Phalaris arundinacea)

This species has choked out native vegetation along shorelines of rivers and in marshes and greatly reduced native biodiversity in those areas. It is very difficult to control because it usually grows in moist to wet areas that are near water and often difficult to access.

Tocalote (aka Maltese starthistle) (Centaurea melitensis)

This spiny, yellow-flowered member of the Aster family looks almost exactly like the dreaded yellow starthistle, but its spines are a bit shorter. Two populations were discovered on Mt. Pisgah’s southern slopes, where FBP crews and volunteers have twice removed it by hand. Additional monitoring and control measures are necessary to curb its spread.

Meadow Knapweed (Centaurea pratensis)

This pink-flowered knapweed has no spines. Like tocalote, it prefers to invade sunny habitats, including meadows and river shorelines. Early invasions can be controlled by repeated hand pullings, but larger infestations may require different methods.

Canada Thistle (Cirsium arvense)

This familiar weed forms patches that spread from underground rhizomes. It is very difficult to get rid of once established. It prefers slightly moist to moist areas, part shade to full sun.

Tansy Ragwort (Senecio jacobaea)

Tansy was very common quite a few years ago until Oregon Department of Agriculture introduced three biocontrol agents (cinnabar moth, flea beetle, seed fly). These insects have reduced its presence significantly, but recently this weed has been increasing again. In response, the insect predators are likely to increase and bring it under control again.

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