How to Care for a Gardenia Topiary
Topiaries are always high maintenance, and gardenia topiaries are no exception. While some topiaries are sliced and diced into complex shapes, a gardenia topiary is usually just a gardenia shrub that has been pruned to be a small tree with a clear trunk and a rounded, pleasing top.
This makes sense because a gardenia's natural shape is somewhat more open and airy, and its leaves are much larger than the typical boxwoods that are pruned into precise figures.
Whether your gardenia (Gardenia spp.) was given to you as a gift and has not yet been planted in the landscape, or you are training an existing gardenia topiary already gracing your yard, the basics of pruning and caring for gardenia topiaries are the same.
Basic Gardenia Care and Pruning
Gardenias usually need little pruning, but they are fussy about their environment, so whether yours is a topiary or maintained in its natural shrub form, take care to provide the environment a gardenia needs to thrive.
You face some challenges if you have a potted gardenia and it's still too cold to plant it out in the landscape. Gardenias require some humidity, which is hard to maintain indoors. Consider running a humidifier or placing the gardenia pot on a tray filled with wet pebbles. However, don't allow the pot to sit in standing water; monitor the water level carefully.
Fertilize with a formula for acid-loving plants. Before planting your gardenia in the landscape, ensure a location with well-draining soil and lots of organic matter.
Sun, Water and Soil
Gardenias can accommodate full sun or partial shade, but too much shade will reduce flowering. Avoid water with a high salt composition, such as water that has been treated with water softeners.
Ensure a location with well-draining soil and a lot of organic matter. Gardenias prefer a slightly acidic environment, with a pH between 5.0 and 6.5; outside of this range, their leaves turn yellow.
Gardenias appreciate regular fertilization, about two to three times per year, ideally in late winter, summer and early fall. Choose a fertilizer formulated for acid-loving plants, such as azaleas and blueberries—these are readily available at any garden store.
General Pruning Tips
As a woody, broad-leaved evergreen shrub, a gardenia requires little pruning. Remove old or weak stems in the summer after the gardenia blooms to encourage new, leafy growth. Avoid hard pruning in the fall, which will result in less growth the following year.
If the plant becomes misshapen or too leggy, prune it in the spring, cutting it within 6 to 8 inches of the ground to encourage new growth. Take care, however, to delay any pruning until your area's last killing frost because new, green growth can be killed by cold, which will set the plant back.
Maintaining a Gardenia Topiary
Your gardenia was pruned by experts into a lovely tree shape, called a "standard" in the nursery trade, and you don't want it to revert to a bush.
So first things first: Prune off any new growth emerging from the trunk as soon as you see it; if it's brand new, you might be able to rub it off with your fingers. Otherwise, use sharp, sterilized pruners to snip off new growth at a 45° angle so that water runs off the cut.
Avoid pruning about six weeks before your area's last frost so that you don't encourage new growth just before cold sets in.
For the crown, perform a light pruning. First, take the time to examine the gardenia's shape, and then start by pruning away anything dead or damaged.
If your gardenia has developed heavy growth in its interior, prune out a few branches, cutting about 1/4 inch from the parent branch, to provide circulation, which will help avoid disease. The general guideline is to prune off no more than 1/3 of the foliage each year, as harder prunings can stress the plant.
Most experts recommend using sharp bypass hand pruners for topiaries rather than hedge trimmers or hedge shears, which are less forgiving when you're trying to achieve a certain shape.
Prune off any branches that mar the shape, snipping to just above a leafy node. Most topiary experts recommend allowing plants to put on at least some growth. For instance, if your topiary began as a small tree with a leafy crown of about a 2-foot circumference, don't try to maintain that size indefinitely.
- Texas A&M Agrilife Extension: Follow Proper Pruning Techniques
- University of Florida IFAS Extension: Gardenias at a Glance
- Purdue University: Gardenia: A Gardener’s Challenge
- Wilson Brothers Gardens: How to Prune, Trim & Maintain a Live Topiary Plant
- Michigan State University Extension: Danish Garden Center Trends: Topiaries, Training and Trellising Plants
I garden in the Pacific North west, previously Hawaii where I had an avocado orchard. I have a Master Gardeners certificate here in Eugene, Oregon.