Blue spruce trees can grow up to 50 feet tall and may spread as wide as 20 feet. These trees have a pyramidal structure, being wider near at the base and tapering to a point at the top. The needles of blue spruce trees are pointed, have a bluish tint to them and grow to less than 2 inches long. Blue spruce trees are known for their slow growth rates and work well as windbreaks, and in ornamental landscaping. Blue spruce trees grow best in full sun in U.S. Department of Agriculture hardiness zones 4a through 7b.
Transplanting Young Spruce
Select a site for the new tree. Blue Spruce prefer moist, rich soil in full sun but are adaptable to other soil types and locations. They grow best in slightly acidic soils (pH of 5.5 to 7.0) but they will grow, only slower in heavy clay soils or those with more alkaline pH values above 8.0.
Decide on the size of spruce to be planted. Container-grown plants are available from nurseries and big box gardening stores. Larger, field grown spruce will have their root systems and adjoining soil encased in burlap ("balled and burlapped"). Barerooted seedlings are also available from tree nurseries.
Dig a planting hole large enough so that the roots of container plants and barerooted seedlings are not bent. Trim any stray roots if necessary. Plant the trees, making sure that the soil is no deeper than one inch above the uppermost roots. The stems of spruces planted too deeply decay and die.
Water thoroughly and deeply to settle the soil and encourage deep root development. Apply a three- to four-inch layer of mulch as wide as the tree canopy, keeping the mulch two to three inches away from the tree's trunk.
In the spring, apply fertilizer formulated for evergreen conifers.
Blue spruce trees are among the most drought-tolerant species of spruces, which means they can survive prolonged dry periods. But to thrive, these trees require moist, well-drained soil with a pH between 6.0 and 7.5. Though they can survive periods of drought, blue spruce trees cannot tolerate flooding and do not do well in soil that retains so much moisture that it remains wet.
Establishing Blue Spruce
To encourage healthy growth, water newly planted blue spruce trees at least once a week during the first year after planting until the ground freezes for the winter. During the hot summer months it may be necessary to water more frequently to keep the ground moist.
Watering Blue Spruce
Feel the soil near the blue spruce tree to a depth of about 1 inch. If the soil feels dry, it is the right time to water the tree. Thoroughly soak the soil around the roots of the tree but avoid over-watering to prevent root rot. If you water a blue spruce tree too much, the water could fill the air pockets in the soil that the roots of the tree need to obtain oxygen. To help the soil retain moisture, spread 3 to 4 inches of mulch around the base of the tree -- this will also help to suppress weeds and moderate the soil temperature.