‘Mission Blue’ blue spruce new growth in spring Pests and diseases The blue spruce is attacked by two species of Adelges, an aphid-like insect that causes galls
 Five years before transplanting, the total root surface area of 2-meter-high trees was doubled by pruning the roots of blue spruce.
 Cultivars Common cultivars (those marked AGM have gained the Royal Horticultural Society’s Award of Garden Merit): • ‘Glauca Globosa’ AGM – shrub from 3–5 feet
(0.91–1.52 m) in height • ‘Fat Albert’ – compact perfect cone to 10 feet (3.0 m) of a silver blue color • ‘Glauca Pendula’ – drooping branches, spreads to about 8 feet (2.4 m) wide by 4 feet (1.2 m) tall • ‘Sester’s Dwarf’ – denser
foliage than the species, slowly grows to about 6–8 feet (1.8–2.4 m) tall • ‘Hoopsii’ AGM • ‘Koster' • ‘Baby Blue Eyes' • ‘Baby Blue' Uses The Navajo and Keres Native Americans use this tree as a traditional medicinal
plant and a ceremonial item, and twigs are given as gifts to bring good fortune.
 Blue spruce always grow naturally in the soils which are in the order Mollisols, and the soil will also be in the orders histosols and inceptisols in a lesser extent.
 Blue spruce is generally considered to grow best with abundant moisture.
 Rooting habits Blue spruce seedlings have shallow roots that penetrate only 6.4 cm (2.5 inches) of soil during the first year.
Canker caused by Cytospora attacks one of the lower branches first and progressively makes its way higher up the tree.
It often first attacks trees which have blown over by the wind and when the larvae mature two years afterwards, a major outbreak occurs and vast numbers of beetles attack
nearby standing trees.
An elongated white scale insect, the pine needle scale feeds on the needles causing fluffy white patches on the twigs and aphids also suck sap from the needles and may cause
them to fall and possibly dieback.
Mites can also infest the blue spruce, especially in a dry summer, causing yellowing of the oldest needles.
The tree can grow larger if the tip is cut when it is at least 3 years old.
 Although freezing can’t damage much in blue spruce, frost will cause seedling loss.
 The blue spruce is susceptible to several needle casting diseases which cause the needles to turn yellow, mottled or brown before they fall off.
 It has been widely introduced elsewhere and is used as an ornamental tree in many places far beyond its native range.
Various rust diseases also affect the tree causing yellowing of the needles as well as needle fall.
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Photo credit: https://www.flickr.com/photos/barkbud/8762189906/’]