Colorado Blue Spruce
The 'Fat Albert' spruce is a cultivar of the Colorado blue spruce (Picea pungens), a species of conifer native to the western United States. It is hardy in U.S. Department of Agriculture plant hardiness zones 3 to 7.
The Colorado spruce is notable for its dense branches covered with stiff, silvery-blue needles. Some cultivars can attain heights of up to 70 feet, and others are ground-hugging shrubs that remain a foot high or less.
'Fat Albert' is a semi-dwarf cultivar that usually reaches a height of between 10 and 15 feet. It gets its name from its wide, pyramidal shape which, with a spread of 7 to 10 feet, may be nearly as wide as the tree is tall. When the tree is young, its width may be particularly pronounced; because its lowest branches are very close to the ground, the immature tree often has a globe-like profile.
Like most Colorado spruce varieties, 'Fat Albert' grows relatively slowly. In good growing conditions, it will add 6 to 10 inches in height per year, and it takes 10 years or more to reach its full mature height. Its growth rate, however, depends largely on climate and cultural conditions. In unfavorable sites or in periods of drought, the tree may only grow 3 to 4 inches per year. Under optimal conditions, it may grow a foot per year.
Best Growth Conditions
Spruce trees grow best in full sun and in soil that is well-drained and slightly acidic, with a pH level between 5.5 and 7. In heavy clay soils that do not drain well, or in alkaline soils, spruces grow more slowly. A 3- or 4-inch layer of mulch around the base of the tree will retain soil moisture and help the tree to grow by decreasing its stress.
A slow-growing tree's growth rate may be enhanced with a spring application of fertilizer. After the last frost and before the middle of June, apply a dry fertilizer with a nitrogen proportion of 10 percent or less. For trees with a trunk diameter of less than 6 inches, apply at a rate of .15 pounds of nitrogen, and for bigger trees, apply .3 pounds of nitrogen. For example, if you're fertilizing a 5-inch tree with a 10-10-10 fertilizer, apply a total of 1.5 pounds of fertilizer. Spread the fertilizer in a circle with a diameter one and a half times the spread of the tree, and water thoroughly after the application.