Habitat Restoration January 2022

Weed of the Month - Shiny Geranium

Winter on the west side of the Cascades is a good time to survey for one of the most aggressive invasive species we encounter on the Refuge. Shiny geranium (Geranium lucidum) is a Eurasian plant species that is not only quick to establish on disturbed open ground but can also infest healthy native landscapes. Listed as a Class B invasive by the state of Washington, and included on the state’s quarantine list, shiny geranium has started to show up as a contaminant in nursery stock. Shiny geranium is shade tolerant and will establish at the base of shrubs and trees and quickly spread underneath a shrub layer. Because the plant stays green after other plants have shed leaves now is the time search it out.

Early detection is crucial to hand removal or covering small patches. One effective covering method is to staple down cardboard over the offending plants and cover with mulch. If hand digging be sure to thoroughly clear plants and roots and bag the material. Shiny geranium is our current “biggest” problem plant within the oak restoration area so if you visit please be sure to use our boot cleaning stations before entering and after visiting the Refuge.

Shiny geranium has the ability to build pressure within the seed pod and literally shoot its seed several meters, so if you have a reproducing patch you will need to expand your search and treatment area.

There are native geraniums, but shiny geranium has “shinier” petals, a redder non-hairy stem, and its petals are more deeply notched, especially the ones closest to the stem. Flowers have 5 petals and the structure the flower is attached to is deeply keeled.

Shiny geranium responds to herbicide, but it will likely take more than one application if patch is well established. Broad leaf herbicides help retain surrounding grasses, but glyphosate is also effective.

-Keith Rutz, FRNWR Habitat Restoration Coordinator