Plant Indicator Species Of Coastal Forested Slopes

The following tables illustrate the great diversity of plants and plant community associations that can be found rowing 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

Sorry, your browser does not support inline SVG. = 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

Sorry, your browser does not support inline SVG. = 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

Sorry, your browser does not support inline SVG. = 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

Sorry, your browser does not support inline SVG. = 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

Sorry, your browser does not support inline SVG. = 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

Sorry, your browser does not support inline SVG. = 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.