Tsuga mertensiana 'Glacier Peak'


Michael's Opinion

This evergreen tree, Tsuga mertensiana, the Mountain Hemlock is quite the beautiful conifer. Its needles are multi coloured with grey-green and blue, to silver-white misting on newer growth; like someone painted each needle individually with such care as to make each one perfect. The needles are soft and thin, small, and abundant on the thin but strong branches. The one in the conifer garden at Fanshawe is still quite small, but its one of my favourite types of tree and I hope that it will be around for many years to come and get to be as high as some of the other trees in the garden.

Botanical Information

FamilyPinaceae
GenusTsuga
Speciesmertensiana
Cultivar'Glacier Peak'
CategoryWoody
TypeShrub (evergreen)
OriginMertensiana is named after a man named Karl Heinrich Mertens, a German botanist who discovered it in 1827. Native to Southern Alaska, along the pacific coast to British Columbia, as well as the mountains to Central California. It is naturalized in Boring, Oregon. A seed was cultivated by Iseli Nursery who named it in honour of the glacier-capped Cascade mountains of Washington and Oregon.
Ethnobotanical Uses
Disclaimer
Today this cultivar is used as ornamental trees/shrubs in small to large, protected microclimate gardens.

Details

USDA Hardiness Zone5
USDA Hardiness Ref.
Canadian Hardiness Zone6b
Canada Hardiness Ref.
RHS Hardiness ZoneH5 - H7
RHS Hardiness Ref.
Temperature (°C)(-29) - (-23)
Temperature (°F)(-20) - (-10)
Height1.5 - 3 m
Spread2.5 m
GrowthFast
Flowering PeriodApril, May

Description and Growing Information

General DescriptionFast growing cultivar, ‘Glacier Peak’ of the straight species, Tsuga mertensiana. This conifer is very attractive in colour, and has soft needles that are dense and abundant on each branch. It comes with an assortment of colours, from green, blue, and silver to grey foliage from new to older growth. Perfect for a protected location where it can grow year-round as a small tree or horizontal cover. A beautiful hemlock to be admired.
ID CharacteristicThe Tsuga species are stately, graceful, pyramidal trees and maintain their good Characteristics into maturity. Needles are soft to the touch. and the blue needles appear silver from afar.
ShapeBroad upright bluish conifer. Narrow cone shape/pyramidal.
LandscapeThe straight species is found on high mountains, and can grow up to 30 M and 15 M wide. It’s a slow growing conifer that prefers mountainous growing conditions. It still performs relatively well in the landscape at lower elevations. This tree is desirable in urban planting locations where other native conifers might quickly outgrow the space. The cultivar ‘Glacier Peak’ is less favourable of open spaces, and it requires a closed in microclimate protected space to grow successfully.
PropagationMountain Hemlock is possibly the least adaptable of the hemlocks. Cultivars are less likely to get very tall or wide.
CultivationSun – mostly sunny, will tolerate partly shaded areas. Even moisture, regular watering. Average well drained rich organic soils. Thrives in highly organic, moist, well-drained soil. Tolerant of partial shade but requires full sun and protected locations.
PestsHemlock borer, hemlock looper, hemlock fiorinia scale, hemlock scale, leaf blight, cankers, blister rust, needle rust, sapwood rot, spruce leaf miner, grape scale, spider mites, woolly adelgid (Adelges tsugae) – leads to decline and death. Highly susceptible to Phytophthora root rot. Also prone to sun scorch and drought injury.
Notable SpecimensThere is a beautiful specimen at Fanshawe college in the conifer garden. It is still rather small but its very beautiful and healthy looking. Protected by the closed in area of the surrounding buildings.
HabitatHorticultural origin.
Bark/Stem DescriptionDark reddish brown with deep, narrow ridges and furrowed.
Flower/Leaf Bud DescriptionLight yellowish green for new growth portions on branches. Buds are rounded and not resinous. They are purple before reaching maturity, changing to a light brown colour.
Leaf DescriptionRadically spreading, 0.85 cm to 0.75 cm (2.5 cm) long, 0.15 cm wide. Obtuse apex, convex above and often keeled, almost round in cross section. Entire, stomatal lines on both surfaces resulting in a blue-green to grey-green colour.
Flower DescriptionGreen, yellow to small purple and brown flower buds turn into large purple cones before turning brown with the season change.
Fruit DescriptionCones 2 to 7 cm long and wide, purple-green maturing brown, are slightly pendent.
Colour DescriptionBluish-green, greyish-silver needles. Shades of purple when young. Green, yellow, purple, and browns for blooming period before cones are ready to release seeds.
Texture DescriptionSoft to the touch. Light to dark green, to blueish silver.

Photographs