Root Growth in Blue Spruces

Seedling Roots

• Seed is the common tree propagation method. The emerging seedlings are shallow rooted with roots growing only 2-1/2 inches long in the first year of growth. This causes loss from frost heaving in soil. Seedling roots are also prone to fatal damage by the root lesion nematode in nursery propagation. Other root diseases include the cylindrocladium root rot.

Mature Tree Roots

• The blue spruce tree remains shallow rooted at maturity. However, the shallow roots have little bearing on the tree's lifespan of 600 years. The tree's roots are sturdy enough to anchor it well in the face of high winds.

Root Pruning

• Tree root pruning reduces the rootball's size around the tree circumference before transplanting. This encourages growth of new feeder roots around the rootball and helps faster establishment in the new site. The blue spruce responds well to root pruning. When roots are pruned 5 years before transplanting, the total surface root area of 6-foot tall trees doubles. Root pruning also increases the root system's density from 40 to 60 percent. This creates a higher transplanting success rate for the blue spruce especially in landscapes.

Soil and Site

• The blue spruce is best adapted to U.S. Department of Agriculture plant hardiness zones 3 to 7 and prefers areas of full sun for optimal growth. Plant it in well-draining, moist, fertile soil. The tree tolerates dry winds and is drought tolerant once established. Blue spruce is good for creating windbreaks and screens in landscape or as individual specimens. However, due to the shallow root system, avoid planting very close to concrete pavings and driveways.