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The Production and Invasion of Buddleja davidii in Oregon Julie Ream with Dr. James Altland Butterfly bush worldwide • Grows on old industrial sites and bomb sites in England • Problem on river bars, floodplains, and forest plantations in New Zealand • Thrives on interstate medians and rivers in Washington state Butterfly bush in Oregon • High value product in nursery, landscape, and retail garden industry • B-listed as a noxious weed Why butterfly bush was listed • Very invasive in certain riparian areas • Grows on many roads in Oregon • As big a problem as scotch broom for some foresters • Thrives where nothing else grows My project goals • To describe in detail the natural sites invaded by Buddleja davidii • To determine nursery production practices that could limit or eliminate invasiveness Natural sites: materials and methods • Site selection: -Planned to do 3-4 sites of each type (riparian, roadside, natural area, old industrial area) in each geographic region -Geographic regions included Portland metro area, Coos Bay area, Oakridge area, and rural North Willamette Valley Natural sites: materials and methods • Marked out the area of each site using set guidelines • Established 5 subplots per site for certain data questions • Simply answered the other data questions Natural sites: observations • Grows everywhere from floodplains to mountain slopes • Appears to be a pioneering species • Densest invasions were on burn sites and regularly disturbed sites • Grows mostly in rocky and sandy soils, but found some in clay soils • Herbicides control it if applied by hand Natural sites: results Drop Page Fields Here Overall density of bushes vs. type of site Average of Overall Density of Bushes (bushes/m2) 0.25 0.2 0.15 Drop More Series Fields Here Total 0.1 0.05 0 Natural Area Old Industrial Type of Site Riparian Roadside Natural sites: results Density of immature bushes (bushes/m2) Density of immature bushes vs. % cover 0.3 0.2 Density of Immature Bushes (bushes/m2) 0.1 0 0 20 40 Cover (%) 60 80 Nursery production: materials and methods • Visited both retail (9) and production (10) nurseries • Asked about management practices • Looked for and collected escaped seedlings Nursery production: observations • Nurseries that did not cut back over winter had more escaped seedlings • Loose cuttings rooted themselves • Most nurseries with escapees were wholesale/production operations Nursery production: results • Determined that 37% of nurseries I visited had escaped seedlings • Of those 37%, 71% were production nurseries Nurseries with escaped seedlings (%) 37% 63% Total % with escapees Total % w/o escapees More to be done • Visit more nurseries and more natural sites • Herbicide trials • Seed tests -when seeds are released -how far wind blows seeds from mother plant -if seeds need heat to germinate Acknowledgements • HHMI Program • OAN and the Nursery Industry • Dr. Mark Wilson of Botany and Plant Pathology Dept. • Rod Jordan of Moore Mills Timber Co. • Jim Carr of Menasha Forest Products • Portland Parks and Recreation • Dr. James Altland of Horticulture Dept. • Steve Wickham of Plum Creek Forest Products • Wanda Crannell, BRR advisor • Tim Butler and Glenn Miller of the ODA • The Nature Conservancy • Bruce Kelpsas of Helena Chemical Company