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shiny geranium (Geranium lucidum)
ODA rating: B
 
USDA Symbol: GELU
Oregon shiny geranium distribution

Other common names
shiny-leaf geranium and shiny-leaf hawksbill

Click on image to view larger photo.
 
Image courtesy of Bruce Newhouse of Salix Associates.

Image courtesy of Bruce Newhouse of Salix Associates.
 

Images courtesy of Molly Juillerat.
If images are downloaded and used from the ODA web site please be sure to credit the photographer.
Description
Shiny geranium grows predominantly as an annual weed though it may become biennial depending on moisture conditions. In Europe, it is described as growing up to 0.5 meters high and being very shade intolerant. Here in the Pacific Northwest, it is predominantly a forest understory species, very shade tolerant and only seen up to 10 -12” high (Newhouse and Brainerd 2006). Stems are red colored growing from a weak central root. Leaves are rounded, deeply lobed with a waxy appearance that makes dense infestations easy to recognize. Flowers are pink, 5 petaled and grow interspersed with the leaves; rather then above them. Geranium lucidum sprouts in the late summer or early fall with the first heavy rainstorm of the season. By early spring, patches of G. lucidum are very pronounced. During April and May, dense low-lying patches form and flowering commences. By late June and July, seed formation is completed and the plant material melts back into the forest floor. The seeds are small and rapidly transported to uninfested areas on boots, vehicles, and by wildlife. Shiny geranium grows in the Pacific Northwest predominantly as an understory species intermixed with grasses, forbs, and moss. Oak woodlands and forest openings are ideal locations for G. lucidum to establish and dominate. Conifer forests offer suitable habitat for G. lucidum though dense second growth plantations often create excessive shade, limiting growth and density.

Impacts
Geranium lucidum has a limited distribution in Oregon and the Pacific Northwest though its effects in oak woodlands, seasonally wet ash forests and on forest edges are quite pronounced. Utilizing the abundance of early spring moisture, Geranium lucidum quickly establishes, then dominates sites pushing out many other early season wildflowers and seedlings of perennial plants. As soils dry few other plants are able to establish through the receding weed canopy. Sites dominated by heavy grass stands or false brome (another invasive plant) may be resistant to significant intrusion.

Introduction
The species has been used in herbal treatments for centuries primarily as a diuretic and an
astringent. Such uses may still occur in Europe and Asia but it is less well known in North America. Geranium lucidum is common throughout much of Eurasia from the British Isles through the Middle East to the Himalayas and India. It also grows in North Africa.
 
Distribution in Oregon
The USDA Plants profile for Geranium lucidum indicates that only California and
Oregon contain populations though Washington now has many confirmed locations.


Biological control
No approved biological control agent is currently available.