Plant of the Week
Blue Spruce
Latin: pica pungens
In a way landscape trees are a kind of time
machine, transporting us back to the period when they were planted. By gazing at
them you can glimpse the choices arrayed before the homeowner as they chose the
trees for their residence. Just as planters grow old and die, so do trees. As
these older trees succumb, a portal to the past closes as they are replanted
with the trees of current fashion.
One of the trees one hardly ever encounters today is the
Colorado Blue Spruce, Picea pungens. In the 1920's and 1930's it was a
tree that proclaimed, "we’ve made it," a kind of silvan status symbol.
The blue spruce is a coniferous evergreen with layered branches
that decrease in length as they ascend the 60-foot trunk, giving the tree a
perfect symmetrical form. In the western mountains where it grows, mostly 6,000
to 10,000 feet from Yellowstone to northern New Mexico, it usually has green
needles and the somber character of most spruces in a forest setting.
But some trees - especially those confined to high, dry places -
develop a waxy bloom on their inch long needles that turn the tree a gorgeous
blue that makes it highly prized as a landscape specimen. This waxy bloom is
produced by glands on the needle surface and can be rubbed off, revealing a
typical green leaf beneath.
To skiers in Colorado, the evergreens on the slopes look more or
less alike. But, thanks to the efforts of a St. Louis doctor named George
Engleman (1809-1884), the world learned of the two spruces that inhabit that
region, the Engleman spruce and the Blue spruce.
Engleman immigrated to the United States in 1832 and eventually
established a medical practice in the rapidly expanding city. While earning his
living in medicine, botany was his passion and as often as possible he would
take extended trips into the unexplored parts of the desert southwest and into
the Rockies. He is probably best known for his work with cacti, but his work
with conifers is equally significant.
He was the first botanist to describe the blue spruce and was no
doubt involved in the first seed collection project that occurred in 1862.
German and Dutch nurserymen were especially fond of the tree and by the end of
the century were making selections of the bluest types and selling grafted
clones. The first and still one of the best of these was ‘Koster’ blue spruce
that was released by a Dutch nursery in 1901.
American nurserymen used a simpler technique. They planted seeds
and selected the bluest seedlings for growing on to salable sizes. After the
trust-busting legislation of the Teddy Roosevelt administration, there was a
general redistribution of wealth and the middle class expanded. Homes were first
on the list of acquisitions for many of these newly well-to-do families.
The largest conifer grower in the nation during the post WW I
period describes the blue spruce as the ultimate status symbol for the era. For
the less-well-off, seedlings with less blue color could be had very cheaply. For
those of moderate income the bluest seedlings could be purchased. For the well
heeled, the grafted selections imported from European nurserymen were available.
But after WWII the nursery industry began changing and container
production became more important. Blue spruce did not readily adapt to growing
in containers in warm climates, so it lost ground to plants better suited to the
new market direction.
Blue spruce is only adapted in the higher elevations of
Arkansas, and even then it suffers from our heat and humidity. In the wilds of
Colorado it may live to be 700 years old, but in landscape situations it usually
becomes so ratty looking by its 60th year that it is taken down. It must be in
full sun with a reasonably fertile, well-drained soil. It should be watered
during dry spells. Bagworms are the most serious pest of the tree, but like most
trees grown out of its natural range, a host of other ailments can afflict it.
By: Gerald Klingaman, retired
Extension Horticulturist
- Ornamentals
Extension News -
January 10, 2003
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