How to Grow and Care for Skyrocket Juniper Tree

One of thirteen junipers native to North America, the Skyrocket Juniper (Juniperus scopulorum) is indigenous to the western United States and Canada. A slow-growing conifer in the cypress family, it is typically narrow and pyramidal in form, growing to 30-40 feet tall. The reddish-brown bark sheds in thin strips and the foliage is silvery-blue to dark green and lies flat against the branches. As additional interest, the cones are waxy blue and berry-like and are enjoyed by birds and small mammals.

Commonly called the Rocky Mountain Juniper, the tree prefers full sun, moist, well-drained soils and does well in dry, sandy soil. It is drought, salt spray, erosion, dry soil, and air pollution tolerant. It does not thrive in wet soils, high humidity, or high night temperatures.

Skyrocket Juniper Care

Once established, a Skyrocket juniper requires very little care. It grows best in full sun in well-draining, dry soils. Since it is slow-growing, pruning is not required other than removing damaged or broken branches. The junipers make an excellent hedge or screen and tolerate most conditions except soggy soils and excessively heavy ice storms.

When planting as a hedge, space the trees at least 24 inches apart to allow for growth while maintaining full privacy coverage. If planted in a well-chosen location, Skyrocket juniper has no serious threats from diseases or insect pests. 

If you desire heavy cone production, plant male and female specimens near each other.

Light

While some cultivars can withstand partial shade, the trees will thrive when planted in full sun or in a location with 6 to 8 hours of sunlight per day.

Soil

This tree is adaptable to loam, rocky, sandy, and even clay soils, the area must be well-draining. Soggy soils will result in root rot and stunted growth. It can tolerate periods of drought, salt spray, and erosion. The soil pH should be neutral - not too acidic or alkaline.

Water

Once established, the trees seldom require supplemental watering. They prefer dry roots. Newly planted trees should be watered deeply once a week or so for several months to establish deep roots and then watered sparingly.

The trees do not fare well in areas with wet winters and can develop root rot.

Temperature and Humidity

Skyrocket junipers prefer cooler climates and low humidity. In rainy areas, they may be susceptible to blights which causes the dieback of the stem tips.

Because they prefer low-humidity areas, the trees are susceptible to injury or death from fires due to their thin, stringy bark and the volatile oils contained in the branches.

Fertilizer

It is usually unnecessary to fertilize this tree unless you have a soil deficiency. However, if you do feed the tree, the juniper will benefit from a slow-release fertilizer feeding in early spring and once again during the growing season. Fertilizers that are high in nitrogen (16-4-8 NPK) will promote lush green growth. Do not feed late in the growing season.

Types of Skyrocket Juniper

There are numerous Juniperus scopulorum cultivars with slightly different foliage and growth patterns.

• Juniperus scopulorum 'Blue Creeper': Blue foliage, low-growing, mounding shape.
• Juniperus scopulorum ''Blue Arrow': Narrow, upright growth with blue-green foliage.
• Juniperus scopulorum 'Wichita Blue': Compact, conical shape with blue to blue-gray foliage, male plant.
• Juniperus scopulorum 'Table Top': Low-growing, flat-topped juniper with silvery-blue foliage, female plant.
• Juniperus scopulorum 'Snow Flurries': Narrow small tree, columnar to fastigiate with blue foliage showcasing creamy white spots.
• Juniperus scopulorum 'Pathfinder': Broader, pyramidical shape with blue-green foliage in flat spray branches.
• Juniperus scopulorum 'Gray Gleam': Slow-growing, dense, columnar tree with silver-gray foliage.
• Juniperus scopulorum 'Cologreen': Upright, narrow form with bright green foliage.
• Juniperus scopulorum 'Blue Heaven': Small, conical tree with light blue foliage.
  

Pruning

The skyrocket juniper is slow-growing and does not require pruning unless you wish to keep the trees short. If a shorter tree is desired, select one of the cultivars that do not grow so tall. The only pruning that is required is to remove any broken or storm-damaged limbs.

Propagating Skyrocket Juniper

1. Select young, healthy, vigorous, semi-hardwood cuttings in mid to late summer.
2. Remove the lower leaves, then coat the cut end with a rooting hormone.
3. Place the cutting in a mixture of perlite and coarse sand, and keep the cutting moist and warm until roots develop.
4. After 8 to 10 weeks, you can transplant the cutting into a larger pot filled with a loam and sand mix.
5. Allow the juniper to develop a hardy root system throughout the fall and winter. Protect the plant from excessive moisture and harsh winds.
6. Transplant to a permanent location in the spring.

How to Grow Skyrocket Juniper From Seed

Growing a skyrocket juniper from seed requires time, patience, and multiple steps.

1. If the seeds are collected late in the season and appear dry, soak the seeds for two days in room-temperature water.
2. Prepare a mixture of equal parts horticultural sand and peat-free compost to fill each small 2-inch pot.
3. Make a small hole in the mixture and add a seed, covering it lightly with the mixture.
4. Place the pot in a shady location outdoors for at least six months and water when the mixture feels completely dry to the touch.
5. Check regularly after a few months and when a seedling appears, move to a larger pot containing a similar mixture.
6. Water the seedlings (but don't keep the soil soggy) and leave them in a cool, shady spot until multiple leaves appear.
7. When the roots have filled the pots, transplant the young trees into one-gallon pots, taking care not to disturb the roots too much.

When the roots have filled the larger pots, dig a hole in a sunny spot big enough to accommodate the root ball in well-draining soil. Carefully ease the plant out of the pot and place it carefully in the hole. Make sure the stem is at the same depth as it was in the pot, and firm backfill the hole with soil. Water deeply for several months until the roots are firmly established.

Overwintering

There are no special requirements for overwintering Skyrocket junipers unless a heavy ice storm is predicted. Use a protective cover to prevent branches from snapping under the weight of the ice.

Common Pests and Plant Diseases

Skyrocket junipers do not have any severe threats from pests or plant diseases. In rainy seasons, they may be susceptible to blights which causes the dieback of the stem tips. Phomopsis twig blight may occur as well as Cedar-apple rust and other rust diseases. In poorly drained soils, root rot can occur. Aphids, bagworms, scale, and spider mites are potential insect pests but seldom kill the tree.

Common Problems With Skyrocket Juniper

The most common complaint about this easy-to-care-for tree is its slow growth pattern. It can take up to 10 years for the tree to reach its mature height.