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Stream Orchid
Epipactis gigantea
About Stream Orchid (Epipactis gigantea) Nurseries Show All Photos Epipactis gigantea is a species of orchid known by the common names stream orchid and giant helleborine. This wildflower is native to western North America from western Canada to central Mexico. This is one of the most abundant orchids of the Pacific coast of North America.

Epipactis gigantea is an erect perennial reaching anywhere from 30 centimeters to one meter in height. Its stems have wide or narrow lance-shaped leaves 5 to 15 centimeters long and inflorescences of two or three showy orchids near the top. Each flower has three straight sepals which are light brownish or greenish with darker veining, each one to two centimeters long. The two top petals are similar in shape and reddish-brown with purple veins. The lowest petal is cup-shaped with a pointed, tongue-like protuberance and is brighter red-brown and more starkly veined, often with areas of yellow. The fruit is a hanging capsule 2 or 3 centimeters long which contains thousands of tiny seeds. This plant grows in wet areas in a variety of habitats, including riverbanks, hot springs, and meadows. Unlike some of its relatives, this species is an autotroph. A distinctive race with burgundy colored foliage is known from The Cedars in Sonoma County California, an area of serpentine rock, and it is called forma rubrifolia (P M Brown).

Epipactis gigantea is cultivated in the specialty horticulture trade and available as a non-wild collected propagated ornamental plant for: natural landscape, traditional, native plant, and habitat gardens. A maroon leaved (forma rubrifolia) cultivar is also grown, called 'Serpentine Night'.
Plant Description
Plant Type
Perennial herb

Max. Height
1 - 2.3 ft (0.3 - 0.7 m)

Max. Width
6 in (15cm)

Upright Columnar


Growth Rate

Summer Deciduous

This species is a monocot with parallel venation in the leaves

Flower Color
Orange, Red, Yellow, Green, Purple, Brown

Flowering Season
Spring, Summer

Native Status

Natural Setting
Site Type
Almost always found in wetland-riparian areas including seeps, wet meadows, and streambanks, adjacent to a variety of other vegetation types, including chaparral, grassland, and several types of woodland or forest.

Part Shade, Sun

Elevation ?
-293' - 8682'

Annual Precip. ?
4.0" - 97.8"

Summer Precip. ?
0.15" - 4.04"

Coldest Month ?
28.3° F - 58.8° F

Hottest Month ?
52.4° F - 87.5° F

Humidity ?
0.09 vpd - 40.41 vpd

Soil Description
Tolerant of sand and clay

Soil Texture
Clay, Clay Loam, Silt, Silt Clay Loam, Silt Loam, Silty Clay

Soil PH
5.0 - 8.0

Fast, Medium, Slow

Cold Tolerance(° F)
Tolerates cold to -10° F

Sunset Zones ?
1, 2, 3, 4*, 5*, 6*, 7*, 8, 9, 10, 14*, 15*, 16*, 17*, 18, 19, 20, 21, 22*, 23*, 24*

Companion Plants
Leopard Lily, Seep Monkeyflower, Scarlet Monkeyflower, Hedge Nettle, various Rushes and Sedges

Wildlife Attracted
Insects, especially flies in the Syrphidae which are the primary pollinators

Landscaping Information
Water Requirement ?
Moderate - High
Extremely Low
Very Low
Moderate - High

Moderately Popular

Max. Summer Water ?
Keep moist
No Summer Water
Keep moist

Propagation ?
Requires mycorrhizal fungi to germinate.

Common uses
Bogs and Ponds, Deer Resistant

Nursery Availability
Commonly Available

Other Names
Common Names
Giant Hellebore, Giant Helleborine, Heleborina Gigante

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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