The blue spruce, Picea pungens, is an attractive evergreen conifer, ideal for adding structure to the garden.
Picea means spruce, and pungens means pointed, in reference to its upright, needle-like leaves. These are covered in a glaucous wax, which gives the tree its characteristic blue-green colour. The cylindrical cones are green, turning pale brown as they ripen. The tiers of horizontal branches form a conical shape that becomes more columnar as the tree grows.
Also known as the Colorado spruce, the blue spruce originates from the Rocky Mountains in the USA. It’s a slow-growing tree but can eventually reach 12m tall. Smaller cultivars are available – many have striking silvery-blue foliage.
How to grow blue spruce
The blue spruce will thrive on any fertile, moisture-retentive but free draining soil with a neutral to acidic pH. Grow in a sunny spot. It does not need pruning. Feed with a balanced fertiliser in spring to encourage healthy growth.
Blue spruce: jump links
- Planting blue spruce
- Caring for blue spruce
- Propagating blue spruce
- Growing blue spruce: problem-solving
- Buying blue spruce
- Best blue spruce to grow
Where to grow blue spruce
Grow on any fertile, moisture-retentive but free draining soil with a neutral to acidic pH, in a sunny spot. The blue spruce looks particularly good planted with other contrasting conifers, winter heathers and other plants with winter interest, such as dogwoods. The blue spruce is drought tolerant when established and is suitable for exposed or windy sites.
How to plant blue spruce
You may find blue spruce available either as a bare-root tree (which will need planting when the tree is dormant, between November and March) or as a pot-grown tree, which can be planted at any time of year.
If you have bought a pot-grown blue spruce for use as a Christmas tree that you now want to plant outside, bear in mind that your tree will be going from a centrally heated home to cool temperatures outside. Acclimatise it gradually by standing in a cool place such as a porch or cool greenhouse for a few days.
- Stand the tree in water to ensure its roots are damp. Dig a square hole that’s wider than the pot your tree is in, and the same depth. Lightly fork the base and sides of the hole to to loosen it
- Stand the tree in the planting hole, checking that the top of the root ball is level with the soil surface
- Backfill with excavated soil around the rootball, then use your heel to firm the soil around it
- Water the tree thoroughly, then keep it well for at least the first year
- Mulch with a layer of bark to help retain moisture while the soil establishes
Read our detailed guide to planting trees.
If you want to grow a blue spruce in a pot, plant out into a larger pot, filled with John Innes No.3 compost. Keep well watered, especially in hot weather in summer.
Caring for blue spruce
The blue spruce does not need regular pruning. You could remove any dead, damaged or crossing shoots in spring. Keep well watered after planting while the roots are establishing; mature plants should get all the moisture they need from rainfall. Feed with a balanced fertiliser in spring to encourage healthy growth.
How to propagate blue spruce
You can grow blue spruce from seeds that have been saved from the cones of a tree or bought online. They need a period of chilling before sowing. Sow at any time of year.
- Soak seeds in water for 24 hours, then drain and place in a freezer bag
- Place in the fridge for 4-6 weeks, checking them weekly to check that they are not drying out
- In a cool greenhouse or cold frame, sow the seeds into 9cm pots filled with peat-free, multi-purpose compost. Sow onto the soil surface, and cover with a very thin layer of vermiculite. They should germinate in a few weeks
- Keep the seedlings in a sheltered spot outside, potting on when necessary. They should be ready to plant out in the garden within three years
You can also propagate blue spruce by taking semi-ripe cuttings in late summer. Read more about taking conifer cuttings.
Growing blue spruce: problem solving
The blue spruce is largely problem free.
Dying foliage on a plant growing in a pot is often due to lack of water or restricted roots.
Adelgids may be a problem – these are aphid-like insects that suck sap. They’re often covered with a waxy coating and you may also spot pineapple-shaped galls on young shoot tips. Damage is usually minor. Control is difficult thanks to the waxy coating, so remove by hand where practical and encourage predators, such as birds, that will eat them.
Advice on buying blue spruce
- You may find bare-root trees available in winter, which need to be planted when the tree is dormant (between November and March)
- Pot-grown trees are widely available at garden centres in the run up to Christmas. Check that the tree is pot-grown (grown in the pot) as opposed to potted (which means it has been dug up from the ground and placed in the pot). A potted plant will have few roots attached to it and will not survive in the pot or in the ground long-term. Pot-grown trees can be planted in the garden at any time of the year
- Blue spruce can reach 12m tall, but smaller cultivars are available – check the ultimate size before you buy
Where to buy blue spruce online
Best varieties of blue spruce to grow
Picea pungens (Glauca Group) ‘Hoopsii’
Picea pungens (Glauca Group) ‘Hoopsii’ has eye-catching, pale silver-blue needles. It is a compact tree, ideal for a smaller garden. It has the prestigious RHS Award of Garden Merit (AGM). Height x Spread: 4m x 1.5m
- Buy Picea pungens (Glauca Group) ‘Hoopsii’ from Crocus
- Buy Picea pungens (Glauca Group) ‘Hoopsii’ from Primrose
Picea pungens (Glauca Group) ‘Globosa’
Picea pungens (Glauca Group) ‘Globosa’ has silver-blue needles. It also has the RHS Award of Garden Merit (AGM). It’s very compact, ideal for a container. H x S: 1.2m x 1.5m.
Picea pungens ‘Waldbrunn’
Picea pungens ‘Waldbrunn’ is an extremely compact and low growing conifer that makes good evergreen ground cover at front of a border or in a rockery. It has blue-grey foliage. H x S: 50cm x 100cm.
Picea pungens ‘Eric Frahm’
Picea pungens ‘Eric Frahm’ has silver-blue foliage and is similar to ‘Hoopsii’, although its leaves are smaller and more dense. H x S: 10m x 3m
Picea pungens ‘Edith’
Picea pungens ‘Edith’ is considered one of the ‘bluest’ of the blue spruces, with ice-blue foliage. It has an upright habit. It holds the RHS Award of Garden Merit (AGM). H x S: 4m x 1.5m