Picea wilsonii
Wilson's Spruce
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Picea wilsonii, or Wilson’s Spruce, is a species of spruce endemic to central China, and one that has seen little use anywhere outside of its natural range. It is a tall evergreen tree that will form a beautiful, large pyramidal form with age. Though a beautiful species of spruce, it has remained in the shadows of its closely related, more popular lookalike Picea abies. The tree is most commonly used for naturalization and reforestation but makes a remarkable ornamental tree in the same ways many common spruce species are already used. As a rare top-tier spruce, it would make a positive addition to any North American garden. The name of this tree comes from Ernest H. Wilson, a famous plant collector known for his expeditions to China in the late 19th century and early 20th century.
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Family |
Pinaceae |
Genus |
Picea |
Species |
wilsonii |
Category |
Woody |
Type |
Tree (evergreen) |
USDA Hardiness Zone |
5a – 7b |
Canadian Hardiness Zone |
4a – 7a |
RHS Hardiness Zone |
H7 |
Temperature (°C) |
-28 – (-23) |
Temperature (°F) |
-18 – (-9) |
Height |
10 - 50 m |
Spread |
4 - 7 m |
General Description |
Picea wilsonii is a large evergreen tree endemic to central China. It grows at a medium rate, and in its natural habitat can reach an impressive 50+ m tall. Wilson’s Spruce has seen little to no use in North America, primarily because of closely related spruce species that are easier to obtain and just as easy to maintain, while also supplying the same vague characteristics as Wilson’s Spruce. |
Landscape |
Common uses are in naturalization and reforestation efforts. It has the possibility to make a great ornamental tree in North America with its long stretching branches and mighty pyramidal form. |
Cultivation |
Similar to many spruces, Picea wilsonii prefers full sun to partial shade. Tolerant of dry and moist conditions, with well-draining moist soil being optimal with neutral to mildly acidic pH levels. There are select North American nurseries offering the Wilson’s Spruce and claiming that the tree is extremely tolerant of salt and urban pollution, although these are questionable statements due to lack of testing. |
Shape |
When young it has a tall, conical form before transitioning into a spreading, pyramidal shape. In maturity, Picea wilsonii can be described as mighty or stoic. |
Growth |
Medium |
ID Characteristic |
Immature cones emerge in colours of bright purple and red, maturing to a light brown. Picea wilsonii is a tall spruce that develops a wider pyramidal form with age. Needles on the top portion of branches will be directed forwards, while needles on the bottom portion of the branch will be spreading. |
Pests |
Green Spruce Aphids could infect this species, however extreme population sizes are required to severely damage the tree. Wilson’s Spruce can also be a host to Needle Rust of Fir, which causes premature foliage death and loss. However, this has only been documented in the wild populations of Picea wilsonii and does not pose any larger risk to the entire species population. Otherwise, the Wilson’s Spruce is a relatively pest-free tree. |
Habitat |
Wilson’s Spruce is endemic to central China, meaning that this is the only place that Wilson’s Spruce naturally occurs. Picea wilsonii can be found growing along mountains and river basins throughout multiple Chinese provinces. It is most commonly found growing between elevations of 1400 m and 1800 m. |
Bark/Stem Description |
New growth starts as a yellowish green or yellowish grey, and transitions to its typical pale grey or brown grey. Bark is glabrous until it reaches maturity, when it becomes irregularly flaky, and greyer in colour. This tree does not develop any thorns. |
Flower/Leaf Bud Description |
Needle buds show up a bright green in the spring. Immature cones show up bright purple or red, before transitioning to a light brown. New growth begins in early spring after a mandatory dormant period. |
Leaf Description |
Dark green needles are slightly curved, and measure 7-15 mm long, and only 1 mm thick. Needles are directed forward and much denser on the top portion of branches, spreading on the bottom portion of the branches. Pushing your hands against them, the needles will have a slight bend to them but will not poke to hurt you. |
Flower Description |
A monoecious tree, with males aligning along the axillary buds, and females being placed at the terminal buds. Early cones are bright purple or red in colour, and transition to a light-medium brown. They are 2-5 cm long and no thicker than 2 cm. Pollination takes place in the late springtime. |
Fruit Description |
Seed cones fully mature in October, are light-medium brown in colour and will be 5-9 cm in length and 2-4 cm thick. Seeds are 3-4 mm long and both seeds and cone scales have an obovoid shape. Seeds of Picea wilsonii have an attached wing measuring 7-10 mm long. |
Colour Description |
Dark green foliage that becomes slightly paler in the winter but will not suffer or look too poorly. New stems on the tree emerge yellowish-grey or yellowish-brown and transition to pale grey or brown. Needle buds emerge bright green and immature cones show up bright purple or red, with mature cones being light-medium brown. |
Texture Description |
Needles of the tree are moderately stiff, but the point is not sharp enough to cause pain. Bark is glabrous until maturity when it starts to flake and irregularly exfoliate. |
Notable Specimens |
There is a quality, mature specimen located at the Birr Castle, County Offaly, in Ireland. Planted in 1912, there is a Wilson’s Spruce located at the Arnold Arboretum in Boston, United States of America, that is most likely the oldest specimen in all North America. |
Propagation |
Propagation by seed is the most common method. To do so, sow the seeds 1-3 mm deep in a slightly compacted media. Keep the seeds moist but not waterlogged, and do not let them dry out. Scarification and stratification are not required by any means. If you wish, you may soak the seeds in water for 24 hours before sowing. Make sure to sow between January and June. Cuttings and grafting are both extremely rare forms of propagation for the Wilson’s Spruce. |
Ethnobotanical Uses (Disclaimer) |
Just like most spruce species, in spring the tips can be gathered and used in a variety of ways, including spruce tea and candied spruce tips. It is not documented how the flavour profile aligns with the most common species of spruce used. Aside from the uplifting effects of tea, there are no known medicinal uses for Picea wilsonii. The wood can be used for construction, as well as small tool making. |