Dwarf varieties of traditional spruce trees have the same colour, texture and shape as their larger counterparts. The only difference is size. Dwarf spruce trees rarely grow taller than 10 feet and they are used as shrubs. They are often grown in rock gardens, planter boxes, pots and under windows. Dwarf spruce varieties often are sold in December as miniature Christmas trees.
Dwarf Alberta Spruce
The most common dwarf conifer is Picea glauca Conica, or dwarf Alberta spruce. This slow-growing spruce, used as a formal foundation shrub, has small, light-green needles and a pyramidal shape. At maturity, it reaches 10 feet tall and 3 feet wide. Its needles appear soft from a distance. It is best suited to sites where air circulates around it on all sides.
There are other dwarf spruces, but they are not as widely available as dwarf Alberta spruce. P. glauca "Jean's Dilly" has an unusual, twisting needle and grows to only 5 feet tall. P. glauca "Pixie Dust" is a more compact and dense form and grows to 8 feet tall. P. glauca "Rainbow's End," also 8 feet tall at maturity, has a midseason second flush of growth tinged yellowish-green or cream-yellow.
Dwarf spruce varieties are native to North America. They require full to part sun and are hardy in U.S. Department of Agriculture Plant Hardiness Zones 2 through 6. Moist, well-drained soil is recommended. Plant them in the fall or spring. Place these shrubs several feet away from the house or any other structure.
Dwarf Alberta spruce is prone to insect infestation, especially from mites that flourish in spring and summer moisture. Spruces planted next to a house or other structure are especially at risk. Mite infestation leads to browning of foliage and stem and needle death. For this reason, the Ohio State University Extension recommends only using this shrub in open areas with good air circulation. An annual pesticide application may also be necessary.