Picea pungens f. glauca (Colorado Blue Spruce)
Michael's Opinion
A very common landscape tree in Southern Ontario, with a wide variety of forms and colours amongst those planted. Cultivars of the form are more consistent and uniform and hence my preference towards them over the form.
Botanical Information
| Family | Pinaceae |
| Genus | Picea |
| Species | pungens |
| Forma | glauca |
| Category | Woody |
| Type | Tree (evergreen) |
| References | The Gradens of Fanshawe College, London, Ontario. |
| Origin | Southwestern United States, introduced to Ontario in 1862. |
| Pronunciation |
Details
| USDA Hardiness Zone | 5 |
| USDA Hardiness Ref. | |
| Canadian Hardiness Zone | 2 |
| Canada Hardiness Ref. | |
| RHS Hardiness Ref. | |
| Temperature (°C) | -46 |
| Temperature (°F) | -10 |
| Height | 40 m |
| Spread | 3-6 m |
| Growth | Medium |
| Flowering Period | May |
Description and Growing Information
| General Description | Picea pungens f. glauca is variable in form and colour intensity. It can be broad and squat to narrowly pyramidal, while colour intensity can vary from a dull blue-green to a rich, intense blue. |
| ID Characteristic | Varying forms and intensity of colour. Needles are four sided, leaving the petiole on the stem when removed. The cones have distinct wavy scales. |
| Shape | Conical/pyramidal. |
| Landscape | Often used as an accent or specimen plant. Suited to windbreak, highway and urban planting since it is highly salt-tolerant. |
| Propagation | Propagated by seed; requires no pretreatment and thus can be sown when ripe or stored for a later date. Cultivars are grafted in January or February. |
| Cultivation | Grows well on most soil types except in wet or boggy conditions. Tolerant of drought, road salt and mild urban pollution. |
| Pests | Aphids, caterpillars, bagworm, gall insects, needle cast, nematodes, rust, saw flies, scale, spider mites and canker. |
| Notable Specimens | The Gardens of Fanshawe College, London, Ontario. |
| Habitat | Southwestern United States. |
| Bark/Stem Description | Blocky, grey-brown. |
| Flower/Leaf Bud Description | Yellow-brown, broadly conical to spherical, blunt, not resinous. Scales loosely appressed and long-pointed. |
| Leaf Description | Spread around the stem, 15-30 mm long and ridged, stout and very prickly, usually a dull grey-green to blue-green colour with the new growth more intense in colour. |
| Flower Description | The tree is monoecious with the small staminate flowers being a deep orange colour while the pistillate flowers are a dull green to purple colour. |
| Fruit Description | Oblong, cylindrical, with a short stalk. Cones are a light beige and are about 5–6 cm long and 2.5 cm wide with wavy scales and toothed at the apex. |
| Colour Description | Blue-green needles, and grey-brown bark. Cones are green when young, tan or beige when ripe. |
| Texture Description | Medium-fine foliage, coarse bark. |
Photographs
Picea pungens 'Thume'.
Picea pungens 'Koster'.
Picea pungens 'Glauca Globosa' standard.
Picea pungens 'Iseli Fastigiate'
Picea pungens 'Hoopsii'.