Picea spp
Spruce species are commonly grown worldwide for both ornamental purposes and timber production. While Colorado blue (P. pungens) and Norway spruce (P. abies) are two of the most common species in landscapes, there are many species native to Europe, Asia, and North America. The English word ‘spruce’ derives from a term that translates to ‘from Prussia’.
- Culture
- Concerns
- Management
Culture for Spruce West
Performs best with moist but well drained, organic-rich, acidic soils. Many species suffer when night temperatures are not sufficiently cold. Shallow root system benefits greatly from mulch and other organic matter additions.
Concerns about Spruce West
Numerous concerns. Needle-cast fungal disease often defoliates older portions of twigs. Cytospora canker causes dieback of branches, particularly in stressed trees. Phytophthora root disease can be a problem in wet or poorly drained soils. Caterpillar defoliators such as tussock moths can be an issue. Also susceptible to spider mites, spruce bud scale, and two different gall forming adelgids (Eastern and Cooley spruce galls). In the western States and Provinces, often attacked by spruce tip weevil, leading to dead terminal leader, and the green spruce aphid, which leads to mottled chlorotic needles and defoliation. Drought stressed spruce also may be attacked by twig borer beetles.
Management Practices for Spruce West
Fertilize according to nutrient analysis, also excellent candidate for root invigoration. Treat mites, scales, aphids, and caterpillars as warranted based on inspection. Needle cast should be treated preventatively in dense plantings or in areas with history of disease. Good cultural care and possibly growth regulation will reduce Cytospora canker.
Photos related to Spruce West
Discolored needles typical of needlecast infection prior to defoliation
Oozing resin is a sign of cytospora canker infection
Chlorotic mottling or banding caused by green spruce aphid