How to Prune a Spiral Topiary

Spiral topiary trees make a stunning focal point in any landscape especially when planted in the midst of a low growing ground cover or when surrounded by a neat border of mulch. There are a variety of evergreen species that lend themselves well to spiral cutting. Once the original spiral shape has been established, all that is required to maintain the shape of your topiary is semi-annual shearing and minor deadwood pruning.

Things You'll Need

• Twine
• Spray-on artificial snow
• Bypass pruning shears
• Curved topiary shears

Instructions

1. Choose a well-shaped evergreen plant with dense foliage. Conifers such as hemlock, juniper and Alberta spruce are commonly used for spirals because all three species respond well to shearing. Boxwood is another popular choice for spiral topiary. A conical or rounded conical shaped plant works best.

2. Fasten a piece of twine at the top of the plant and arrange it evenly in a wide descending spiral on the outer foliage of the tree ending in a full circle at the widest part of the base.

3. Following the string as a center line, use a water-soluble spray-on artificial snow product to mark the foliage that will remain after pruning. The marked area of the plant should be wider than the spiral that remains green. The entire top few inches of the tree should be marked. Pruning will begin below that. Even before pruning begins, you should now easily be able to visualize how the pruned topiary will appear. Now is the time to apply any finishing touches to the marked pattern.

4. Starting at the top, carefully reach in toward the trunk and identify the branches whose outer foliage remains green. Remove these one by one at the trunk using a bypass pruner or secateur working all the way down to the bottom of the plant. Remove the string and use a hose to rinse away the artificial snow.

5. Finish by judiciously clipping the remaining foliage into an inwardly curved form using topiary or grass shears. It is better to remove too little foliage than too much. Clip again after the last frost and before mid-summer each year. Each successive trimming will help the plant produce a tighter surface of foliage. This, in turn, will make it easier to achieve a more finished sculpted appearance.

Tips & Warnings

• Topiaries planted in the landscape tend to require less care than potted topiaries, which require a rigorous schedule of watering and fertilization.

• The best time to plant your spiral topiary outdoors is late fall.

• Always be sure your pruning tools are sharp and clean. Dirty or dull tools can cause permanent damage to your plants.

• Clip with caution, sheared plants do not admit as much light as naturally growing plants so inner branches are often bare. Once these bare branches have been accidentally exposed by over-pruning, repair can take a long time.

References

• Topiary Growing Guidance
• Pruning Ornamental Shrubs