Blue Star juniper is a needled evergreen shrub with silvery-blue, densely-packed foliage. If you take a bird's-eye view of the shrub, you will notice that the clusters of needles atop the tiny stems resemble stars. The needles are awl-shaped, unlike the long, slender needles, such as those that grow on eastern white pine trees, with which many people are most familiar. A member of the cypress family, this shrub is a conifer. The female cones are berry-like, with one seed. This slow-growing plant is a dwarf, forming a compact mound that reaches just 1 to 3 feet in height at maturity. It tends to grow out rather than up. Along with certain types of wildflowers and native plants, this may be one of the lowest-maintenance plants you could possibly choose to grow in the landscape.
|Common Name||Blue star juniper, flaky juniper, Himalayan juniper, singleseed juniper|
|Botanical Name||Juniperus squamata 'Blue Star'|
|Mature Size||1 to 3 ft. tall, 1.5 to 3 ft. wide|
|Soil pH||Acidic, alkaline|
|Hardiness Zones||4-8 (USDA)|
Watch Now: How to Grow and Care for a Blue Star Juniper
Blue Star Juniper Care
As dwarf shrubs, blue star junipers are effective specimens for very small spaces, such as in plantings for narrow patio areas or in foundation beds. For larger spaces, they can be used as edging plants or as ground covers. Because they are drought-tolerant once established, they are a good choice if you wish to include a dwarf shrub in your rock garden (they are not suited to small rock gardens but could work in larger ones). The bluish color of Blue Star juniper goes well with plants with golden foliage.
Plant new shrubs in a shallow, broad hole that is as deep as the root ball and three times as wide. Add some compost to the soil and replace the soil up to the base of the plant. Give the new plant a good watering. cover the ground around it with a 2-inch layer of mulch, but keep the mulch 4 inches away from the stem. Water new plants weekly during the first growing season.
Plant this small evergreen bush in full sun. Give it an open, sunny space with good distance to other herbaceous plants or large shrubs.
Its natural preference is for light, sandy soil but blue star juniper does well in a variety of soil types, from slightly acid to alkaline (pH 5.0 to 8.0), as long as they are well-drained. It does not tolerate water-logged soil.
Make sure to water these dwarf evergreen shrubs properly their first year in the yard so that they can become established, then let them go. Water established plants occasionally when they look dry, or more often in extreme heat, keeping in mind this plant doesn't like overly wet conditions. They are relatively drought-tolerant shrubs once mature.
Temperature and Humidity
Having developed in the mountains of Asia, the blue star juniper will not do well in areas with high heat and humidity.
You will only need to fertilize blue star juniper in the late winter or early spring of its first year. Use a general 10-10-10 fertilizer. For the amount to use, follow the product label instructions. Once established, it won't need routine fertilization. Fertilize your plants by applying compost to the soil.
Types of Juniper squamata
There are no other varieties of Blue Star juniper but there are other cultivars of Juniperus squamata, including:
- Juniperus squamata 'Meyeri' is the cultivar from which Blue Star originated as a sport. It has a more upright habit, so it would not work as well where a short, spreading shrub is needed.
- Juniperus squamata 'Floreant' has two-toned, light and dark foliage. Its compact growth habit also makes it suitable for growing in containers.
- Juniperus squamata 'Dream Joy' has white foliage in the spring, which makes this compact shrub stand out.
Their slow growth rate means that Blue Star juniper shrubs hardly ever have to be pruned unless you are trying to fit them into an area with very little room.
One thing to be aware of is that this plant can experience a sudden growth spurt following several years of no significant increase in size. So it might happen that it perfectly fits into a tight spot without any need for pruning for a long time and then it may sneak up on you size-wise and will require pruning.
Because Blue Star is a cultivar, the only way to propagate a plant true to type is the vegetative way, through stem cuttings, and not through seeds. Here's how it's done:
- In the late fall or winter, using a sharp knife or pruners, cut off a strong stem at least 5 inches long. Remove any side shoots and the needles from the lower portion of the stem.
- Fill a 4-inch pot with potting mix and dip the cut ends in rooting hormone. Make a hole in the soil with a pencil or stick and insert the cutting in the hole. Water well until the soil is evenly moist.
- Place the pots in a protected outdoor location such as a cold frame that gets bright, indirect light. Keep it evenly moist.
- In the spring repot any cuttings that have rooted to larger individual pots and let them grow in pots for a couple of seasons. The stronger they are when transplanted, the better their chance of survival in the landscape.
Potting and Repotting
To grow Blue Star juniper in a container, choose one that is at least 8 inches wider than the nursery container so it has room to grow for at least two to three years before requiring repotting. The preferred container material is terracotta so the container does not topple over easily.
Like all container plants, Blue Star grown in a pot needs more frequent watering than in garden soil, especially during the hot summer months.
Blue Star is a hardy evergreen that can tolerate winters up to USDA zone 4 without protection. Potted plants, however, need to be moved to a sheltered outdoor location. The containers should also be insulated as the roots don't have enough soil around them to protect them from the winter cold. You can winterize the container by wrapping the container in burlap or bubble wrap.
Common Pests & Diseases
Blue Star juniper is a tough shrub that is mostly unbothered by pests and diseases when planted in well-drained soil. Soggy soil can lead to root rot. Any disease or bug-pest problems will generally occur on these shrubs only in hot, humid regions. One such problem is spider mites. If you detect spider mites on your plant in time, you can simply hose the bush down with a very strong spray. This may knock the pests off. Check your bush regularly thereafter to ensure that the spider mites do not return. Repeat the hosing-down as needed. Deer do not eat blue star junipers (probably because the foliage is so bristly), making them a deer-resistant shrub.
Is Blue Star juniper a ground cover?
Botanically it is a shrub but since it is so low-growing, the dense, globe-shaped foliage makes it an attractive ground cover.
Can you grow Blue Star juniper in a container?
How far apart should I plant blue star junipers?
It depends how you want to use them. For individual specimens, plant them 6 to 8 feet apart, measuring from the center of the plant. As a groundcover, plant them densely, about 2 feet apart.