Side by side
Colorado blue spruce or Norway spruce? How to tell them apart
Picea pungens · Picea abies
You can tell a Colorado blue spruce by its very stiff, sharply pointed, blue-grey to silver-blue needles and its cones of 6–10 cm; a Norway spruce has green, less prickly needles, longer cones of 10–15 cm and side shoots that hang down like curtains.
Look at the colour and carefully grasp a shoot: on the Colorado blue spruce the needles are bluish from a waxy coating and really prick, on the Norway spruce they are green and stiff but less sharp. Both have four-sided needles all round the shoot, on small woody pegs, and hanging cones. Not every Colorado blue spruce is equally blue: there are greener forms too.
Photo: USDA-NRCS PLANTS Database / Herman, D.E. et al. 1996. North Dakota tree handbook. USDA NRCS ND State, Public domain · source
Colorado blue spruce Picea pungens
| Colorado blue spruce | Norway spruce | |
|---|---|---|
| Needles | Needles 2–3 cm, square in cross-section, very stiff and sharply pointed, blue-grey to silvery blue (‘Glauca’), all round the shoot on small woody pegs. | Needles 1–2.5 cm, stiff, pointed and square in cross-section (you can roll them between your fingers). They grow all round the twig on small woody pegs that remain when the needle falls. |
| Flowering | – | – |
| Cones and seeds | Hanging, light brown cones of 6–10 cm with crinkly scale edges. | Hanging, cigar-shaped cones 10–15 cm that fall whole. |
| Bark | Grey and scaly. | Red-brown, thin and flaking in small round scales. |
| Shape and height | Conifer, 15–25 m (in gardens usually 10–15 m) | Conifer, 30–50 m |
| Site | Full sun, any garden soil, normal | Sun or partial shade, acid soil, normal |
| Native to Belgium | No, planted | No, naturalised |
| Good for bees, butterflies and birds | Yes, for birds | Yes, for birds |
| Poisonous to people and pets | Not known to be poisonous | Not known to be poisonous |
| Pruning months | May–June | August–September |
The best feature in each season
- Spring
- In May the buds burst: the young shoots of the Colorado blue spruce are often silver-blue, those of the Norway spruce fresh light green. On both, the cones form mainly high in the crown.
- Summer
- The shape gives them away: the Colorado blue spruce is a regular, dense cone with branches down to the ground; the Norway spruce has a narrow crown with long, hanging side shoots.
- Autumn
- The cones are ripe: light brown, 6–10 cm, with crinkled scale edges on the Colorado blue spruce; cigar-shaped and 10–15 cm on the Norway spruce. On both they fall whole.
- Winter
- Evergreen, so you can compare them all year. Look at the bark: grey and scaly on the Colorado blue spruce, reddish-brown and flaking in small round scales on the Norway spruce.
Where do they grow?
The Colorado blue spruce comes from the Rocky Mountains and is found here mainly in gardens, parks and Christmas tree nurseries. The Norway spruce grows naturally in the mountains and the north of Europe; here it is found in many forestry plantations, especially in the Ardennes.
Which one for your garden?
- At 30–50 m the Norway spruce is too big for a garden and is easily blown over in storms; for a small garden, dwarf forms such as the bird’s nest spruce are better. The Colorado blue spruce also reaches 10–15 m tall and 5 m wide in gardens: for a small garden, choose a slow-growing or dwarf form.
- Both are shallow-rooted, and the ground under the crown is dry and acidic: little grows there. The needles of the Colorado blue spruce are very sharp: do not plant it next to a path, a play area or a seating area. In our damp climate it is also prone to green spruce aphid.
Did you know? The needles of both spruces sit on small woody pegs that stay on the shoot when the needle falls: a bare spruce twig therefore feels rough as a rasp, while a bare silver fir twig feels smooth.
Read on
- Plant profile: Colorado blue spruce
- Plant profile: Norway spruce
- Colorado blue spruce: when and how to prune
- Norway spruce: when and how to prune
- Identification key: the question that separates them