The Black Hills Spruce (Picea glauca ‘Densata’) is a popular and hardy evergreen, known for its dense, conical shape and attractive deep green to blue-green needles. This cultivar of white spruce is highly adaptable and suitable for various landscapes, often used as a specimen tree, for privacy screens, or as a windbreak due to its compact growth and low maintenance needs. This guide provides comprehensive instructions for successfully planting and caring for this resilient tree.
Choosing and Preparing the Planting Site
A proper planting site ensures the Black Hills Spruce’s long-term health. The tree thrives in full sun (at least six hours daily) but tolerates partial shade, though growth may be slower. Protection from strong winds benefits young trees. Given its mature size (30 to 70 feet tall, 15 to 25 feet wide), adequate space is necessary to prevent crowding.
Black Hills Spruce adapts well to various soil conditions, including clay, loam, and sand, but requires well-drained soil to prevent root rot. It prefers slightly acidic to neutral soil, with a pH range of 4.0 to 7.5. If your soil is heavy clay or very sandy, amending it with organic compost can improve drainage and fertility.
When preparing the planting hole, dig it two to three times wider than the root ball, but only as deep as the root ball’s height. Ensure the root collar, where the trunk flares out before meeting the roots, rests at or slightly above ground level. Planting too deep can hinder the tree’s establishment and overall health.
When to Plant Black Hills Spruce
Key planting times ensure successful establishment of Black Hills Spruce. The best periods are early spring, after the last frost, or early fall, several weeks before the first hard freeze. These cooler temperatures and often moist conditions allow the tree to establish its root system with less stress.
Planting during these seasons helps the tree adapt before facing extreme heat in summer or severe cold in winter. Avoiding mid-summer heat and drought, or late winter’s frozen ground, reduces transplant shock and increases survival.
Step-by-Step Planting Process
Begin by removing the Black Hills Spruce from its container or burlap wrapping. Inspect the root ball for any circling roots, loosening them to encourage outward growth once planted. Place the tree in the prepared hole, ensuring the root collar is positioned at or slightly above the surrounding soil level.
Once the tree is properly positioned, begin backfilling the hole with the original soil, mixing in some organic compost if desired. Tamp the soil around the root ball to remove any large air pockets, but avoid compacting it too firmly.
After backfilling, water the tree deeply to settle the soil around the roots. This initial deep watering helps eliminate any remaining air pockets and ensures good contact between the roots and the soil. Apply a 2 to 4-inch layer of organic mulch, such as shredded bark or composted leaves, around the base of the tree. Keep the mulch a few inches away from the trunk to prevent moisture buildup and potential disease issues.
Initial Care After Planting
Consistent, deep watering is important for a newly planted Black Hills Spruce during its first year. Water deeply, especially during dry periods, to ensure the soil is moist down to the root ball. While regular watering is necessary, it is equally important to avoid overwatering, which can lead to root rot. Check the soil moisture by feeling about three inches deep before watering again.
Staking is not necessary for Black Hills Spruce unless the planting site is very windy or the tree is young and unstable. If staking is required, use flexible ties and ensure they do not girdle the trunk as the tree grows. Proper staking allows for some natural movement, which encourages stronger trunk development.
Protecting young trees from potential threats helps ensure their survival. Voles and deer can sometimes browse on young evergreens, so physical barriers like tree guards or fencing can help. In exposed areas, especially in colder climates, wrapping young trees with burlap in late fall can protect them from winter desiccation and harsh winds.
Long-Term Care and Maintenance
Once established (after the first year or two), Black Hills Spruce trees become more self-sufficient regarding water. They are drought-tolerant, requiring supplemental watering mainly during prolonged dry spells. Deep watering during these periods helps maintain their health.
Fertilization is not needed for established Black Hills Spruce trees unless a soil test indicates specific nutrient deficiencies. If necessary, apply a balanced fertilizer in early spring, at least one year after planting. Avoid fertilizing after August, as this can stimulate new growth that may be vulnerable to winter damage.
Black Hills Spruce has minimal pruning needs due to its naturally dense, conical shape. Pruning should focus on removing any dead, damaged, or diseased branches, which can be done at any time. Major shaping or size reduction should be done in late winter or early spring before new growth begins, but avoid topping the tree or heavy pruning that alters its natural form.
Regularly inspecting the tree for signs of common pests, such as spider mites, aphids, or bagworms, and diseases like needle cast, helps in early detection and management. While these issues are rarely severe enough to kill a healthy tree, addressing them promptly can prevent significant damage.