January Tree of the Month-Colorado blue spruce

Evergreens are the kings of ‘Winter Interest’, a term I often use because of its importance in the garden. Winters can be LONG. A third of the year in St. Louis gardens is spent in dormancy. That’s a long time to look at a bare patch of mulch while you wait for your bulbs or perennials to emerge. Deciding on just what evergreens to include in your garden takes research. There is an evergreen for every garden!  

Nothing seems to beat the visual impact of a Colorado blue spruce, Picea pungens, in a sea of winter burn, dull greens, straw-colored grasses, and bare branches. Blue spruces come in all sizes, from dwarf cutie-pies perfect for containers to giants that tower 30′ or higher. Rule # 1 in gardening is RESEARCH! Read nursery plant tags and look the plant up online using the botanical name, not the common name to avoid confusion. 

The globe-shaped Colorado spruce (P. pungens’ Globe’ or P. pungens’ Glauca Globosa’)above is most common in the trade around the STL metro area. These shrubs can grow up to 5′ high and wide and also come as a Standard, more commonly called “Lollipop,” resembling a mini tree perfect for small gardens.

The common name “Colorado” should be the first clue that they will have issues in St. Louis. We trade enough cool mountain air for flatlander heat and humidity to send any Colorado native running. If Colorado spruces had legs, they would run, too. Diseases are not limited to needle cast, cytospora canker, and rust. Look out for bagworms, aphids, and spider mites as well. Despite all the issues, it makes my heart sing to come across a mature specimen-many are found in the older neighborhoods of St. Louis and St. Louis County.

How do you keep a Colorado spruce happy here in the Midwest? Rich but well-drained soil and good air circulation are critical, but don’t let the soil dry out too long, especially when the tree is young and still getting established. Full sun is preferred for a perfect shape. And nothing makes a Colorado native happier than a good wet, sloppy snow. 

What I love about this plant;

-Very low-maintenance shrub-no trimming or shearing required!

-Great blue color year-round.

-Deer and rabbit tolerant!

-Comes in every shape and size.

-Will carry heavy, wet snow without damage, unlike arborvitae. 

What I’m not crazy about-

-Can have disease and pest problems in St. Louis. Keep an eye out for bagworms!

Words and photos by Jo Batzer

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