Bloom Period and Seasonal Color
Grown mostly for its Christmas tree like shape and blue-green needles
Mature Height x Spread
30 to 50 feet x 10 to 20 feet. There are also dwarf and weeping forms that are shorter.
Native, deer resistant
This classic evergreen tree is a standard for Christmas trees, but also makes an excellent large specimen in the yard and a great informal hedge. There are also dwarf, weeping and creeping forms that look beautiful combined with other shrubs and flowers. The horizontal, stiff branches hold their shape well and the attractive blue needles make this tree noteworthy, especially in winter. The blueness of the needles varies depending on the tree you select. It grows slowly in a conical shape and produces small cones. The needles are stiff and sharp making this also a good tree to plant in hedges to keep out wildlife. It makes a nice living Christmas tree, as long as it’s planted into the ground right after the holiday.
When, Where and How to Plant
Colorado blue spruce is hardy in our region. Purchase trees from a local nursery or garden center. Plant trees in full sun from spring to summer in well-drained, slightly acidic, humus-rich, moist ground. Space specimen trees 20 to 30 feet apart. Plant weeping, creeping and dwarf forms closer together.
Although blue spruce trees are more drought tolerant than other types of spruce, keep trees well watered. In a lawn setting, create a mulch ring around trees and add bark mulch, pine needles or wood chips to keep the soil moist and protect the trees from damage due to string trimmers and lawn mowers.
Regional Advice and Care
Colorado blue spruce grows naturally into a beautiful, pyramidal shape. You can prune the growth tips on branches in spring to shape the tree even more if desired. They usually form branches to the ground when grown in full sun. Insects, such as the spruce gall aphid, can cause growth tips to dieback and deform individual branches. Spider mites can cause poor growth on new branches. Spray insecticidal soap to control this pest. Colorado blue spruce are tolerant of salt spray, so can be planted along roads or the near the ocean.
Companion Planting and Design
Plant Colorado blue spruce as a specimen tree in a large yard. Mix it with other large evergreens, such as fir trees, to create an informal hedge to block a view. Birds and other wildlife will appreciate the winter cover these trees provide. Plant dwarf forms in a mixed shrub border with other evergreens. Plant weeping tree types in the garden as a focal point plant. Plant creeping types on a bank or cascading over a wall.
‘Thompsen’ and ‘Hoopsii’ are two common large, pyramidal varieties with good needle color and plant shape. ‘Fat Albert’ is a dwarf blue spruce that grows 20 feet tall with good blue needle color. ‘Glauca Pendula’ is a creeping or weeping variety, depending on the selection. ‘Glauca Globosa’ is a shrub form that grows 4 feet tall and wide.
Excerpted from my book, New England Getting Started Garden Guide.