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Sunday, November 22, 2015



Sunday, 9:30 AM.  21 degrees F at both the ferry dock and the back porch.  Wind SSW, calm with moderate gusts.  The sky is clear, the sunshine bright.  The humidity is 78% and the barometer falling, now at 30.06".  It is a cold but pleasant day.
   The Colorado blue spruce, Picea pungens, in the Pine Family, the Pinaceae, is a very large conifer, that can reach a height of well over 100' in its native habitat of the mountains of the southwestern US.  It prefers a moist loam soil but is quite tolerant of various soil and moisture conditions, withstands drought and is hardy north.  
   Because it is a very attractive tree, the Colorado blue spruce has been universally over-planted, its main landscape features being its blue-green to silver-blue needle color and its formal, conical shape. The silver-blue trees are very expensive. Only about 10% of Colorado spruce seedlings have a truly blue color of new needle growth, so the true-blue color demands a premium.  Many of the silvery-blue trees sold at nurseries are patented, grafted selections, which are also very expensive.  
   It is sometimes difficult for many to distinguish a spruce tree from a fir tree, but there are some easy clues.  The needles of the spruce species are quite characteristic in being very stiff and sharp, also in the fact that they are rather square in cross section.  An easy way to distinguish spruce from fir needles is that you can roll a spruce needle in your fingers; a fir needle is flat and won't roll.  Another easy way to distinguish spruce from fir species is that spruce and most other conifer species cones are pendent (they hang down). Fir cones are borne upright on the branches.
   Colorado blue spruce is rather ubiquitous in American landscaping, and of course has held this position because it is esthetically attractive, but it has lately become subject to a very disfiguring, ultimately fatal,  needle   -cast fungus which is difficult to control, and unless a good cure or preventative comes along, I can no longer recommend it.  And, The further away from its native range it is planted, the more subject it seems to be to other insect and disease problems. such as spruce gall (caused by an aphid), canker and red spider mite (can be severe in hot, dry conditions).

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