Plant Indicator Species Of Coastal Forested Slopes
The following tables illustrate the great diversity of plants and plant community associations that can be found growing on Puget Sound shorelines. There are other plants that you may be familiar with which are not listed.
The influences of Puget Sound’s intricate waterways, the surrounding mountains, and long term human impacts have contributed to a wide variability in plant occurrence and range. Some species are found only in specific locales while others are seen throughout the region.
Representative trees, shrubs, and herbaceous species have been included to furnish readers with information relating to the assessment of relative slope stability and other characteristics of the vegetation found on a given shoreline area. Caution should be exercised in the use of the tables; natural processes and vegetational development is more complex than can be represented here.
For those more comfortable with common names; an index of common names is provided.
This list is not to be used in determining appropriate species for use in revegetation and restoration of slopes on Puget Sound. Neither should it be considered an exhaustive list of species occurring on coastal slopes in this region. Nature is more variable and complicated than can be competely represented in a chart. This table is necessarily a simplification. The attributes described in this table are accurate only for forested coastal bluffs on Puget Sound. In using this information all of the species present on a slope should be considered. Large old trees can be considered an indicator of stability. Small, young trees are often an indicator of recent disturbance or instability. For purposes of this list, marine riparian areas are considered by their nature to be disturbed. A wet hydrologic regime often indicates unstable conditions on slopes. For this reason, wetland species are considered a warning sign of potential slope instability. Species marked as both deciduous and evergreen may show vegetative growth during mild coastal winters.
Lowest Strata: Groundcovers, Subshrubs, And Vines
= Non-Native Invasive Plant — Usually indicative of disturbed and/or unstable conditions
| Botanical Name | Common Name | Life Form | Successional Stage | Hydrologic Regime | Tolerance | Erosion Control Value | Relative Slope Stability |
|---|---|---|---|---|---|---|---|
| See Common Name Index for Cross Reference | A=Annual P=Perennial H=Herbaceous W=Woody D=Deciduous E=Evergreen O=Overstory Canopy U=Understory Canopy |
E=Early T=Transitional L=Late |
W=Wet M=Moist D=Dry |
SS=Salt & Spray S=Shade NI=No Information |
D=Detrimental V=Variable EC=Surface Erosion Control SS=Slope Stabilization |
U=Unstable V=Variable D=Disturbed S=Stable |
|
| Arctostaphylos uva-ursi | Kinnikinnik | P, W, E | T | D | EC | D | |
| Blechnum spicant | Deer Fern | P, H, D, E | T, L | W, M | S | EC | S |
| Carex spp. (1) | Sedge | P, H, D, E | T, L | W, M, D (1) | S | EC | U, V |
| Cirsium arvense | Canada Thistle | P, H, D | E | M, D | D | U, D | |
| Cornus unalaschkensis | Bunchberry | P, H, D | T, L | M, D | S | EC | S |
| Digitalis purpurea | Foxglove | P, H, D | E | D | D | U, D | |
| Epilobium angustifolium | Fireweed | P, H, D | E, T | D | D, V | U, D | |
| Equisetum spp. (2) | Horsetail | P, H, D, E | E, T | W, M, D (2) | S | EC, D, V | U, D |
| Fragaria spp. (3) | Strawberry | P, H, D | T, L | M, D | SS, S | EC | S |
| Hedera helix | English Ivy | P, W, E | T, L | M, D | SS, S | D | U, D |
| Heracleum mantegazzianum | Giant Hogweed | P, H, D | E | M, D | S | D | U, D |
| Juncus spp. | Rush | P, H, D | E, T, L | W, M | S | EC | U, V |
| Linnaea borealis | Twin Flower | P, H, D, E | E, T, L | M, D | S | EC | D, S |
| Lysichiton americanum | Skunk Cabbage | P, H, D | L | W | S | V | |
| Mahonia nervosa | Low Oregon Grape | P, W, E | T, L | M, D | SS, S | EC | S |
| Maianthemum dilatatum | False Lily of the Valley | P, H, D | T, L | W, M, D | SS, S | EC | V |
| Mimulus guttatus | Monkey Flower | P, H, D | E, T | W, M | V | ||
| Polygonum cuspidatum | Japanese Knotweed | P, H, D | E, T | W, M, D | S | D | U, D |
| Polystitchum munitum | Swordfern | P, H, D, E | T, L | M, D | SS, S | EC | D, S |
| Potentilla pacifica | Silverweed | P, H, D | E, T | W, M | SS | U | |
| Pteridium aquilinum | Bracken Fern | P, H, D, E | E, T | M, D | D, V | U, D, V | |
| Rubus ursinus | Trailing Blackberry | P, W, D, E | E, T | D | SS, S | EC | D, V |
| Tiarella trifoliata | Foam Flower | P, H, D | T, L | M | S | EC | U, V |
| Tellima grandiflora | Fringecup | P, H, D | T, L | D | S | EC | D, S |
| Tolmiea menziesii | Piggyback Plant | P, H, D | T, L | M, D | S | EC | D, S |
| Urtica dioica | Stinging Nettle | P, H, D | E, T | M, D | S | EC, V | D, V |
Middle Strata: Shrubs and Small Trees
= Non-Native Invasive Plant — Usually indicative of disturbed and/or unstable conditions
| Botanical Name | Common Name | Life Form | Successional Stage | Hydrologic Regime | Tolerance | Erosion Control Value | Relative Slope Stability |
|---|---|---|---|---|---|---|---|
| Acer circinatum | Vine Maple | P, W, D, U | E, T, L | M, D | S | EC, SS | D, S |
| Acer glabrum (4) | Douglas Maple | P, W, D, O | T, L | D | SS | SS | D, S |
| Amelanchier alnifolia | Serviceberry | P, W, D | E, T, L | D | SS, S | EC, SS | S |
| Arctostaphylos columbiana | Hairy Manzanita | P, W, E | T, L | D | SS | EC, SS | S |
| Buddleia davidii | Butterfly Bush | P, W, D | E, T | D | D | U, D | |
| Ceanothus sanguineus (5) | Red-stem Ceanothus | P, W, D | E, T | D | NI (SS) | EC, SS | D, S |
| Ceanothus velutinus (5) | Snowbrush | P, W, E | E, T | D | NI (SS) | EC, SS | D, S |
| Cornus stolonifera | Redtwig Dogwood | P, W, D | E, T | W, M, D | NI (SS) | EC, SS | D, V |
| Corylus cornuta | Beaked Hazel | P, W, D | E, T, L | M, D | S, SS | EC, SS | D, S |
| Crataegus douglasii | Black Hawthorn | P, W, D | T, L | W, M, D | S | EC, SS | D, S |
| Cytisus scoparius | Scot’s Broom | P, W, D | E, T | D | SS | D | U, D |
| Gaultheria shallon | Salal | P, W, E | T, L | D | SS, S | EC | S, V |
| Holodiscus discolor | Oceanspray | P, W, D | E, T, L | D | SS, S | EC, SS | S, V |
| Ilex aquifolium | English Holly | P, W, E | E, T, L | M, D | SS, S | D | D |
| Lonicera hispidula | Purple Honeysuckle | P, W, D | T, L | D | SS | EC | S |
| Lonicera involucrata | Twinberry | P, W, D | T, L | W, M, D | SS, S | EC, SS | S |
| Mahonia aquifolium | Tall Oregon Grape | P, W, E | E, T, L | D | SS | EC, SS | S |
| Oemleria cerasiformis | Indian Plum | P, W, D | T, L | D | S | EC | S |
| Philadelphus lewisii | Mock-orange | P, W, D | T | D | SS | EC, SS | S |
| Physocarpus capitatus | Pacific Ninebark | P, W, D | T, L | W, M | S | EC, SS | S |
| Rhododendron macrophyllum | Bigleaf Rhododendron | P, W, E | T, L | D | S | EC | S |
| Ribes lacustre | Swamp Gooseberry | P, W, D | T, L | W, M | EC | U, V | |
| Ribes sanguineum | Redflowering Currant | P, W, D | T, L | M, D | SS | EC, SS | S |
| Rosa eglanteria | Sweetbriar Rose | P, W, D | E, T | W, M, D | NI, SS | D | D |
| Rosa gymnocarpa | Baldhip Rose | P, W, D | T | D | S | EC, SS | S |
| Rosa nutkana | Nootka Rose | P, W, D | T, L | M, D | SS | EC, SS | D, S |
| Rosa pisocarpa | Swamp Rose | P, W, D | T, L | W, M, D | S | EC, SS | S |
| Rubus discolor (=R. ameniaca); | Himalayan Blackberry | P, W, D, E | E, T | M, D | SS | D | U, D |
| R. laciniatus | Cutleaf Blackberry | P, W, D, E | E, T | M, D | NI (SS) | D | U, D |
| Rubus parviflorus | Thimbleberry | P, W, D | T | M, D | SS, S | EC | D, V |
| Rubus spectabilis | Salmonberry | P, W, D | E, T | W, M, D | SS, S | EC, D | D, V |
| Sambucus racemosa | Red Elderberry | P, W, D | E, T | M, D | S | EC | D, V |
| Shepardia canadensis | Soapberry | P, W, E | T | D | SS | EC, SS | D, S |
| Symphoricarpos albus | Common Snowberry | P, W, D | T | D, M | SS | EC, SS | D, S |
| Ulex europaeus | Gorse | P, W, E | T | D | SS | D | D |
| Vaccineum ovatum | Evergreen Huckleberry | P, W, E | E, T, L | D | S | EC | S |
| Vaccineum parvifolium | Red Huckleberry | P, W, D | E, T, L | D | S | EC | S |
Upper Strata: Trees
= Non-Native Invasive Plant — Usually indicative of disturbed and/or unstable conditions
| Botanical Name | Common Name | Life Form | Successional Stage | Hydrologic Regime | Tolerance | Erosion Control Value | Relative Slope Stability |
|---|---|---|---|---|---|---|---|
| Abies grandis | Grand Fir | P, W, E, O | T, L | M, D | SS, S | SS | S |
| Acer macrophyllum | Bigleaf Maple | P, W, D, O | T, L | M, D | SS, S | SS | S |
| Alnus rubra | Red Alder | P, W, D, O | E, T | W, M, D | SS | V, SS | U, D, S, V |
| Arbutus menziesii | Pacific Madrone | P, W, E, O | E, T, L | D | SS | SS | D, S |
| Cornus nuttallii | Pacific Dogwood | P, W, D, U | T, L | D | S | SS | S |
| Picea sitchensis | Sitka Spruce | P, W, E, O, U | L | W, M, D | SS, S | SS | S |
| Pinus contorta | Shore Pine | P, W, E, O | T | M, D | SS | SS | S |
| Pinus monticola | Western White Pine | P, W, E, O | T, L | M, D | SS | SS | S |
| Prunus emarginata | Bitter Cherry | P, W, D, O | E, T | M, D | SS | SS | D, S |
| Pseudotsuga menziesii | Douglas Fir | P, W, E, O | E, T, L | D | SS | SS | S |
| Quercus garryana | Oregon White Oak | P, W, D, O | T, L | M, D | SS | S | |
| Rhamnus purshiana | Cascara | P, W, D, U | T | M, D | S | EC, SS | D, S |
| Salix hookeriana | Hooker’s Willow | P, W, D, O | E, T | W, M | SS | SS | D, V |
| Salix scouleriana | Scouler’s Willow | P, W, D, O | E, T | M, D | SS | SS | D, V |
| Taxus brevifolia | Pacific Yew | P, W, E, U | L | M, D | SS, S | SS | S |
| Thuja plicata | Western Red Cedar | P, W, E, U, O | L, T | W, M, D | SS, S | SS | S |
| Tsuga heterophylla | Western Hemlock | P, W, E, U, O | T, L | M, D | S | SS, V | S, V |
Notes
(1) Carex deweyana occurs in moist forest understories. Carex Inops and C. tumulicola occur on well-drained prairies, coastal rocky balds, and coastal sandy bluffs. All other Carexes occur in wet situations.
(2) Equisetum hyemale may occur in both wet conditions and on sandy well-drained coastal bluffs.
(3) The three coastal Fragaria species in the Puget lowlands may occur in open coastal and forested areas.
(4) Acer glabrum is locally common in the San Juan Islands; otherwise rare in the Puget lowlands.
(5) These Ceanothus species occur from Hood Canal north on the Olympic Peninsula. They require episodic fire for natural germination and establishment.
Common Name Index
Lowest Strata: groundcovers, subshrubs, & vines
= Non-Native Invasive Plant — Usually indicative of disturbed and/or unstable conditions
| Common Name | Botanical Name |
|---|---|
| Bracken Fern | Pteridium aquilinum |
| Bunchberry | Cornus unalaschkensis |
| Canada Thistle | Cirsium arvense |
| Deer Fern | Blechnum spicant |
| English Ivy | Hedera helix |
| False Lily of the Valley | Maianthemum dilatatum |
| Fireweed | Epilobium angustifolium |
| Foam Flower | Tiarella trifoliata |
| Foxglove | Digitalis purpurea |
| Giant Hogweed | Heracleum mantegazzianum |
| Horsetail | Equisetum spp. |
| Japanese Knotweed | Polygonum cuspidatum |
| Kinnikinnik | Arctostaphylos uva-ursi |
| Low Oregon Grape | Mahonia nervosa |
| Monkey Flower | Mimulus guttatus |
| Piggyback Plant | Tolmiea menziesii |
| Rush | Juncus spp. |
| Sedge | Carex spp. |
| Silverweed | Potentilla pacifica |
| Skunk Cabbage | Lysichiton americanum |
| Stinging Nettle | Urtica dioica |
| Strawberry | Fragaria spp. |
| Trailing Blackberry | Rubus ursinus |
| Twin Flower | Linnaea borealis |
Middle Strata: shrubs and small trees
= Non-Native Invasive Plant — Usually indicative of disturbed and/or unstable conditions
| Common Name | Botanical Name |
|---|---|
| Baldhip Rose | Rosa gymnocarpa |
| Beaked Hazel | Corylus cornuta |
| Black Hawthorn | Crataegus douglasii |
| Butterfly Bush | Buddleia davidii |
| Common Snowberry | Symphoricarpos albus |
| Cutleaf Blackberry | Rubus laciniatus |
| Douglas Maple | Acer glabrum |
| English Holly | Ilex aquifolium |
| Evergreen Huckleberry | Vaccineum ovatum |
| Gorse | Ulex europaeus |
| Hairy Manzanita | Arctostaphylos columbiana |
| Himalayan Blackberry | Rubus discolor (=R. ameniaca); |
| Indian Plum | Oemleria cerasiformis |
| Mock-orange | Philadelphus lewisii |
| Nootka Rose | Rosa nutkana |
| Oceanspray | Holodiscus discolor |
| Pacific Dogwood | Cornus nuttallii |
| Pacific Ninebark | Physocarpus capitatus |
| Pacific Rhododendron | Rhododendron macrophyllum |
| Purple Honeysuckle | Lonicera hispidula |
| Red Elderberry | Sambucus racemosa |
| Red Huckleberry | Vaccineum parvifolium |
| Red-Flowering Currant | Ribes sanguineum |
| Red-stem Ceanothus | Ceanothus sanguineus |
| Redtwig Dogwood | Cornus stolonifera |
Upper Strata: overstory trees
= Non-Native Invasive Plant — Usually indicative of disturbed and/or unstable conditions
| Common Name | Botanical Name |
|---|---|
| Bigleaf Maple | Acer macrophyllum |
| Bitter Cherry | Prunus emarginata |
| Cascara | Rhamnus purshiana |
| Douglas Fir | Pseudotsuga menziesii |
| Grand Fir | Abies grandis |
| Hooker’s Willow | Salix hookeriana |
| Oregon White Oak | Quercus garryana |
| Pacific Madrone | Arbutus menziesii |
| Pacific Yew | Taxus brevifolia |
| Red Alder | Alnus rubra |
| Scouler’s Willow | Salix scouleriana |
| Shore Pine | Pinus contorta |
| Sitka Spruce | Picea sitchensis |
| Western Hemlock | Tsuga heterophylla |
| Western White Pine | Pinus monticola |
| Western Red Cedar | Thuja plicata |
The information presented here is from the author’s personal observations, the observations of colleagues in related fields, and a variety of published sources, as listed below:
- Burns, R. M. and B. H. Honkala, Technical Eds. 1990. Silvics of North America, Volumes 1 and 2, Agricultural Handbook 654. USDA Forest Service.
- Haeussler, S., et al. 1990. Autecology of Common Plants in British Columbia: A Literature review. FRDA Report 158. Canada-BC Forest Resource Development Agreement Project.
- Klinka, K., et al. 1989. Indicator Plants of Coastal British Columbia. University of British Columbia Press.
- Lesher, R. D. and J. A. Henderson. 1992. Indicator Species of Forested Plant Associations on National Forests of N. W. Washington. R6-MBS-TP-041-1992. USDA Forest Service.
- Menashe, E. 1993. Vegetation Management: A Guide for Puget Sound Bluff Property Owners. Pub. No. 93-31. Shorelands and Coastal Zone Management Program. Washington Department of Ecology.
- Minore, D. 1979. Comparative Autecological Characteristics of Northwestern Tree Species: A Literature Review. GTR-PNW-87. USDA Forest Service. PNW Forest and Range Experiment Station.
Readers who have additional information, additional bibliographic citations, or comments are invited to contact the author.