Classification, origin and diffusion
It is a tree native to the central-western regions of North America, from western Wyoming to New Mexico. Imported to Europe in the mid-nineteenth century.
Colorado spruce var. Glauca - Picea pungens Engelm. (photo www.connonavk.com)
Colorado spruce var. (photo www.aujardin.ch)
Size and bearing
Tree up to 40 meters high, with pyramidal and dense crown.
Trunk and bark
It has an erect trunk with monopodial growth, dense branches, red-gray flaky bark.
The leaves are tetragonal needle-like, up to 3 cm long, green or glaucous, rigid and pungent, inserted completely in a radial pattern on the branch.
It is a monoecious plant: the male flowers are in small apical reddish strobilis, the female ones green, first erect then pendulous and yellowish-brown (8 cm long). The scales, wide at the base, shrink towards the middle to end in a narrow apex.
Used as an ornamental plant, many park and even dwarf cultivars have been selected.
There are several mostly ornamental varieties, among which the most renowned are: [no source]
- Picea pungens var. Koster (Kosteriana) and var. Glauca: with gray-blue hair.
- Picea pungens var. Fat Albert: it is a fairly compact variety, with a naturally pyramidal shape, with deep blue needles.
- Picea pungens var. Hoopsii: has a regular crown (although not always), with the branches slightly turned upwards at the ends. It has long, pointed needles in a silvery blue color, more intense in the spring. It is not very demanding as regards the reaction of the soil, as long as they are neither too alkaline nor too acidic. It resists temperatures up to -35 ° C. It has elongated pendulous cones, mostly present at the top of the plant, which when ripe are light brown in color.