Mountain Hemlock
Tsuga mertensiana
- Native to:
- Canada, United States
Walter Siegmund (talk)
Taxonomy
- Division:
- Coniferophyta | - Conifers
- Family:
- Pinaceae
- Genus:
- Tsuga
- Species:
- Tsuga mertensiana
- USDA Symbol:
- TSME
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Tree
- Height:
- 4000 cm
- Light Requirements:
- Full Sun,Part Shade,Shade
- Drought Tolerance:
- Low
- Bloom Months:
- apr,may,jun
Wildlife Benefits
- Caterpillars:
- ★★☆☆☆ Recorded caterpillar host plant (HOSTS Database)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★★★ Butterfly & moth species supported by this genus (NWF)
Host Plant for Caterpillars
Apotomops wellingtoniana, Eupithecia annulata, Eupithecia longipalpata, Eupithecia palpata, Eupithecia spermaphaga, Eupithecia unicolor, Imitated Melanolophia (Melanolophia imitata), Syngrapha rectangula
Reported Fauna Sightings
Butterflies:Anise Swallowtail (Papilio zelicaon), Anna Blue (Plebejus anna), Cabbage White (Pieris rapae), California Sister (Adelpha californica), California Tortoiseshell (Nymphalis californica), Clodius Parnassian (Parnassius clodius), Common Buckeye (Junonia coenia), Common Checkered-Skipper (Pyrgus communis), Coronis Fritillary (Speyeria coronis), ⚠️Edith's Checkerspot (Euphydryas editha), Field Crescent (Phyciodes pulchella), Great Basin Fritillary (Speyeria egleis), Hoary Comma (Polygonia gracilis), Hoffmann's Checkerspot (Chlosyne hoffmanni), Lilac-bordered Copper (Lycaena nivalis), Lorquin's Admiral (Limenitis lorquini), Lupine Blue (Plebejus lupini), Lustrous Copper (Lycaena cupreus), Mexican Cloudywing (Thorybes mexicana), ⚠️Monarch (Danaus plexippus), Mourning Cloak (Nymphalis antiopa), Mylitta Crescent (Phyciodes mylitta), Northern Checkerspot (Chlosyne palla), Northwestern Fritillary (Speyeria hesperis), Orange Sulphur (Colias eurytheme), Pacific Fritillary (Boloria epithore), Pacific Orangetip (Anthocharis sara), Painted Lady (Vanessa cardui), Pale Swallowtail (Pterourus eurymedon), Propertius Duskywing (Erynnis propertius), Rocky Mountain Dotted Blue (Euphilotes ancilla), Sandhill Skipper (Polites sabuleti), Sheridan's Green Hairstreak (Callophrys sheridanii), Sierra Blue (Plebejus podarce), Sonoran Skipper (Polites sonora), Sooty Hairstreak (Satyrium fuliginosa), Spring White (Pontia sisymbrii), Square-dotted Blue (Euphilotes battoides), Western Pine Elfin (Callophrys eryphon), Western White (Pontia occidentalis), 🛑Zerene Fritillary (Speyeria zerene)
Garden & Ecology Notes
- Wildlife Value:
- birds, small mammals
- Deer Resistant:
- Yes
- Fire Notes:
- Mountain hemlock is thin-barked and highly susceptible to fire damage; typically occurs in moist, high-elevation sites with infrequent fire.
Soil Requirements
- Soil Type:
- moist, well-drained, acidic soil
- pH:
- 4.5 - 6.0 (acidic to slightly acidic)
- Drainage:
- excellent drainage required
- Moisture:
- consistently moist
- Notes:
- prefers high organic matter content
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 60–120 days
- Germination Time:
- 14–42 days
- Notes:
- Seeds require light for optimal germination. Cold stratification improves germination rates significantly.
The above propagation data sourced from Claude AI
Pre-treatment: Seeds are placed in cold moist stratification for 30-90 days
Establishment: T. mertensiana is found from 0 to 2400 m elevation; from Alaska and British Columbia south to California, Montana, Idaho, and Nevada. It is also commonly found on the western coast of North America. There is a conflict in the pre-treatment protocol duration between the two sources.
Source: npn.rngr.net