The striking vertical form of many of the popular cultivars of evergreens, including Rocky Mountain juniper (J. scopulorum), Chinese juniper (J. chinensis), and arborvitae (Thuja occidentalis), offer an important and unique element in the landscape. They direct our eyes upward without being overly demanding of precious horizontal real estate. Used alone or as a platoon of soldiers at attention, they serve their “landscape” as powerful specimens, small groupings, or as extensive screens or hedges.
The cultivar I’m most excited to add to my list of tried and true performers in this category is Star Power™ juniper (Juniperus chinensis Star Power™ [‘J.N. Select Blue’]). I’ve been admiring it for the past few years for its great ornamental and favorable production characteristics. After last winter’s harsh treatment of evergreens, I also admire its winter burn resistance relative to other junipers.
Name: Juniperus chinensis ‘J.N. Select Blue’
Trade name: Star Power™
Hardiness: Zones 3 to 6
Mature height (~20 years): Up to 17 feet
Mature spread (~20 years): Up to 7 to 9 feet
Classification: Upright evergreen
Landscape use: Specimen, grouping or hedge; outstanding focal point or backdrop for other landscape plants
Ornamental characteristics: Pronounced, blue-green, pointed juvenile needles with a silvery upper edge that radiate around stems for the first 15 years of the plants’ life. Adult plants maintain the fast growth and develop scaly, bluegreen foliage typical of the species. The plant is dense, symmetrical, fast growing and provides great color and texture year round.
Junipers are generally more winter-burn tolerant than other species, but the winter of 2013-14 definitely put them to the test. The upper Midwest can be especially challenging for winter burn with our frequent combination of winter sun, cold and low humidity. Landscape professionals in our region have learned to stick to the more tried and true cultivars (‘Techny’, ‘Technito’, and ‘Pyramidalis’ arborvitae, ‘Wichita Blue’ juniper, some of the forms of our native eastern red cedar, and so on). Care in the Midwest and other regions should also be had with cultivars of Rocky Mountain cedar (J. scopulorum) where the fungal pathogen Phomopsis is prevalent.
Star Power™ (J. chinensis) not only shows promising winter burn and Phomopsis resistance, but also combines important ornamental and practical traits important for it to be a success in the industry. The blue-green, awl-shaped needles are large, have a silvery stripe on their upper surface, and radiate beautifully around the stems. The 3-D, star-shaped effect of the pointed juvenile needles and its great growth rate inspired its clever name.
It a delight to grow for both the production phase as well as after it is in the landscape. Plants are incredibly uniform, dense and robust. They have an early growth rate about 25 to 40 percent greater than other popular upright junipers (6 to 7 feet in five years). Making up size fast and looking consistent and full in a pot contributes substantially to profitability and puts it literally head and shoulders above the competition.
The gorgeous juvenile foliage is star-like and continues for a long time during the life of this plant, changing to mature tissue once plants exceed 15 years of age. Adult tissue has the scaly foliage typical of the species, which also is attractive and has the beautiful bluish green color of the juvenile foliage.
Like other junipers, Star Power™ does best in sites with full sun, modest to moderate nutrition, slightly acidic to moderately alkaline pHs and welldrained soil. Star Power™ keeps its plump, upright form throughout its lifetime and, because of the strength of its branches, it typically requires minimal to no pruning to maintain its great shape. With its blue-green color and fine to medium texture, it can be a wonderful backdrop for some of the colorful leaved cultivars of elderberry, ninebark and smokebush, flowering shrubs like mockorange, wiegela and roses, and the larger growing dramatic herbaceous perennials.
Star Power™ is from the work of well-known woody plant propagator and breeder Mike Yanny from JN Plant Selections in Menomonie Falls, Wisconsin. He identified it over 20 years ago in an open pollinated lot of J. chinensis seedlings.
The pronounced, pointed juvenile needles not only provide distinctive beauty, but contribute to its deer resistance. Star Power™ is routinely propagated by grafting onto J. chinensis ‘Hetzii’ as a rootstock. In addition, it is one of the few upright junipers that can be rooted reliably from cuttings. The list of licensed growers of this great new plant is expanding. Reports from across the Midwest are all very favorable.