If you are developing a juniper cultivar known as “Spartan” (Juniperus chinensis “Spartan”), you are probably knowledgeable about its tall, narrow shape. A Chinese juniper, this variety reaches 15 to 20 feet tall, but only grows 4 to 5 feet wide. Although this evergreen does not require routine pruning, a “Spartan” juniper that’s becoming too tall or contains some spreading branches near its top can be cut back successfully, as long as you follow several guidelines.
Selecting the best Time
“Spartan” juniper grows in U.S. Department of Agriculture plant hardiness zones 5 through 10, getting partially dormant in winter, when its growth slows. It is possible to do a small amount of light pruning at any given time, but in case you are intending to do major pruning, it’s ideal to postpone this until early spring, just before the dormant buds open and new growth appears. This takes advantage of the new flush of spring growth that starts soon after your pruning semester, while also letting you remove any divisions damaged or broken during winter storms. Avoid doing any major pruning in late summer.
Trimming the very best
To trim the surface of a “Spartan” juniper, cut the terminal end of each branch to remove the final, or apical, bud. This encourages development of new side shoots, encouraging the plant to become more full and giving it a powerful shape. Junipers are typical evergreens and can not produce new growth from brownish, leafless branches, known as “dead wood.” When pruning, you can cut the branches back badly, but make sure that you leave some green leaf on the plant and do not cut so drastically that only dead wood stays, because this can destroy the shrub. To prune the top back more gently, trim back about one-third of those divisions in the initial pruning semester, then repeat this again during the next two seasons to complete the job. Sterilize your pruning blades by wiping them with a cloth soaked in rubbing alcohol between cuts. This helps prevent the spread of plant diseases.
More Trimming and Tying
After you prune back the very top of a “Spartan” juniper, watch the new growth to decide if you need to shape the tree more. When side branches appear, you can prune back any that protrude outside the main canopy to help preserve the juniper’s narrow, columnar form. If only a few branches need trimming, you can do it at any given moment. For more major trimming, delay until the next spring. If branches start to lean away from the main portion of the plant since they produce new development, it is possible to keep these in position by using soft ties or plastic straps, which you can buy in nurseries, anchoring them into main branches to train them into position. Leave these in place until tender new growth strengthens, which can take a year or two.
Giving Extra Care
Junipers are usually tough shrubs that need little special care, tolerating drought and other tough conditions well. But after providing a “Spartan” juniper a major pruning, provide the plant some additional care. Make sure it gets about 1 inch of water weekly, including water from rain. Water the plant during dry spells, especially during the summer. Insert a 3- to 4-inch layer of organic mulch under the canopy to help conserve soil moisture and keep down weeds. Do not allow the mulch touch or rest against the plant’s back, since this can encourage infection and decay.