Guidebook to Invasive Nonnative Plants of the Elwha Watershed Restoration Olympic National Park, Washington Cynthia Lee Riskin A project submitted in partial fulfillment of the requirements for the degree of Master of Environmental Horticulture University of Washington 2013 Committee: Linda Chalker-Scott Kern Ewing Sarah Reichard Joshua Chenoweth Program Authorized to Offer Degree: School of Environmental and Forest Sciences Guidebook to Invasive Nonnative Plants of the Elwha Watershed Restoration Olympic National Park, Washington Cynthia Lee Riskin Master of Environmental Horticulture candidate School of Environmental and Forest Sciences University of Washington, Seattle September 3, 2013 Contents Figures ................................................................................................................................................................. ii Tables ................................................................................................................................................................. vi Acknowledgements ....................................................................................................................................... vii Introduction ....................................................................................................................................................... 1 Bromus tectorum L. (BROTEC) ..................................................................................................................... 19 Cirsium arvense (L.) Scop. (CIRARV) .......................................................................................................... 35 Cytisus scoparius (L.) Link (CYTSCO) ......................................................................................................... 45 Digitalis purpurea L. (DIGPUR) .................................................................................................................... 55 Geranium robertianum L. (GERROB) .......................................................................................................... 63 Hedera helix L. ssp. helix (Stace 1997) (HEDHEL) .................................................................................... 73 Hedera helix L. ssp. hibernica (Stace 1997) (HEDHIB) ............................................................................ 73 Ilex aquifolium L. (ILEAQU) .......................................................................................................................... 84 Lathyrus latifolius L. (LATLAT) .................................................................................................................... 95 Lathyrus sylvestris L. (LATSYL) ................................................................................................................... 95 Phalaris arundinacea L. (PHAARU) .......................................................................................................... 104 Polygonum cuspidatum Sieb. & Zucc. (POLCUS) .................................................................................... 117 Polygonum sachalinense (POLSAC) .......................................................................................................... 117 Polygonum xbohemicum (POLBOH) .......................................................................................................... 117 Potentilla recta L. (POTREC) ....................................................................................................................... 129 Rubus armeniacus Vest. (RUBARM) ......................................................................................................... 139 Rubus laciniatus Willd. (RUBLAC) ............................................................................................................. 139 Senecio jacobaea L. (SENJAC) .................................................................................................................... 151 Glossary ......................................................................................................................................................... 165 Appendix: Nonnative Species Present as of 2011 in the Elwha Watershed .................................... 175 i Guidebook to Invasive Nonnative Plants of the Elwha Watershed Restoration Figures Figure 1: Lake Aldwell before Elwha Dam removal ................................................................................... 2 Figure 2: At the border of Olympic National Park, near Madison Falls, Elwha River ......................... 3 Figure 3: A female Chinook salmon excavates a nest in the Elwha River ............................................ 4 Figure 4: Former Lake Aldwell, October 22, 2012 .................................................................................. 10 Figure 5: Drained Lake Aldwell—a difficult place to grow plants ....................................................... 12 Figure 6: B. tectorum infestation ................................................................................................................ 20 Figure 7: B. tectorum seeds showing long, straight awns ..................................................................... 21 Figure 8: B. tectorum lemma, awn .............................................................................................................. 21 Figure 9: Ligule fringed, sheath closed only at bottom ......................................................................... 22 Figure 10: B. tectorum roots ........................................................................................................................ 25 Figure 11: Plant turns purple at maturity................................................................................................. 27 Figure 12: C. arvense ..................................................................................................................................... 35 Figure 13: Hairless stems lack wings ......................................................................................................... 36 Figure 14: Rosette (juvenile) stage ............................................................................................................. 36 Figure 15: First true leaves .......................................................................................................................... 38 Figure 16: Leaves are densely white-hairy beneath ................................................................................ 38 Figure 17: Fluffy white pappi help disperse seed in wind .................................................................... 39 Figure 18: Highway crews have planted C. scoparius to control erosion .......................................... 45 Figure 19: Year-round green stems makes C. scoparius look green overall when not in bloom .. 46 Figure 20: Bilabiate--two-lipped flower. .................................................................................................... 48 Figure 21: Pods are green, with hairy edges, turning brown in summer ........................................... 49 Figure 22: Monocultures are common ....................................................................................................... 50 Figure 23: Foxglove is so common that many think it's native to the Pacific Northwest. ............. 55 Figure 24: In the rosette stage, toxic D. purpurea is easily confused with other plants ............... 56 Figure 25: Drooping flowers have spots inside ....................................................................................... 58 Figure 26: G. robertianum can grow just about anywhere ................................................................... 63 Figure 27: Red foliage on exposure to sun or cold ................................................................................. 64 Figure 28: The rounded, lobed foliage and 5-petaled flower of G. robertianum ............................. 65 Figure 29: Dicentra formosa. ....................................................................................................................... 65 Figure 30: G. robertianum seedlings, just outgrowing their kidney-shape ....................................... 66 Figure 31: G. robertianum stems are hairy .............................................................................................. 67 Figure 32: Beaked G. robertianum fruits .................................................................................................. 68 Figure 33: Invasive ivy infesting a forest understory ............................................................................ 74 ii Figure 34: Mature, shrub form .................................................................................................................... 75 Figure 35: Modest-size roots being removed ........................................................................................... 76 Figure 36: Unusual situation of mature form growing prostrate with juvenile form ..................... 77 Figure 37: Mature leaves, flowers, and fruit ............................................................................................ 78 Figure 38: Invasive ivy killing a deciduous tree ...................................................................................... 79 Figure 39: Ilex aquifolium ............................................................................................................................. 85 Figure 40: Berberis aquifolium yellow flowers .......................................................................................