Bird's nest spruce (Picea abies "Nidiformis") is a dwarf, multistemmed, evergreen shrub hardy in U.S. Department of Agriculture plant hardiness zones 3 to 7. Its new foliage emerges lime green in spring. The shrub gets its common name from a depression in the center that makes it look like a bird's nest. It generally forms a compact ball but can be pruned into other shapes. Severe pruning is not needed because the shrub grows slowly. However, light pruning is recommended because it helps the shrub develop a denser crown and rids it of dead branches.
Shape the bird's nest spruce into the desired form and size in late May or early June. Use small hedge shears to make slanting cuts on limbs that grow upward, which prevents water from pooling in the cuts. Leave at least one live bud on each pruned branch, pruning 1/2 inch above the bud; otherwise, the branch will likely die.
Lightly prune new growth as it develops, maintaining the shrub's shape. If two leading shoots develop on the top of the bird's nest spruce, prune back the weaker one using bypass clippers to keep the shrub structurally sound.
Prune out lower branches of an older bird's nest spruce to open up the canopy. Branches thicker than a pencil may require a pruning saw.
Cut off branches identified with disease, pruning back to the nearest living lateral branch or to the main stem of the bird's nest spruce. Prune these branches in late winter before diseased spores are released in the spring. Cut off shoots infected with bug invasions. Put the diseased or insect-infected cuttings in a garbage bag and dispose of them. Disinfect the shears with a 10 percent bleach solution between cuts and after all infected material has been removed to avoid spreading the disease.
Prune away dead or damaged bird's nest spruce branches, cutting them off flush with the main stem. You can prune dead branches throughout the year as long as the weather is dry. Otherwise, remove them in late May or early June when you do the rest of your pruning.