These gardenias, freeze damaged in December, showed no signs of recovery in March. Photo by H. N. Kolich, UGA Extension.

While some landscape shrubs rebounded from the extended December deep freeze, others have not. A freeze-blackened hedge of gardenias has been a source of debate in my household: Do we continue exercising patience or dig them out and plant something new?

On close examination, the upper stems are flexible (a good sign), but the inner stems are brown, indicating dead tissue (a bad sign).

A stem of a gardenia which has been scraped to show more brown stem beneath. This indicates it is dead.
Brown stem tissue: Brown tissue under the bark indicates the stem is dead. Photo by H. N. Kolich, UGA Extension.

With all stems on these erstwhile evergreen shrubs showing dead leaves, brown tissue, and no new leaf buds, it’s worthwhile to consider replacement plants. Before completely giving up on this established gardenia hedge, however, I spent two hours last weekend giving each plant a renewal pruning.

Renewal pruning is a technique used to reduce the size of overgrown shrubs – and sometimes as an opportunity to reshape shrubs into a more desirable form – by pruning the shrub down until the branches are just 6-12 inches above the ground. Mid-March is a good time to do renewal pruning.

Most broadleaf shrubs are good candidates for renewal pruning. It can be reinvigorating for azaleas, camellias, ligustrum, abelia, and other landscape shrubs. Because of the timing, shrubs that flower on floricane, or second year wood, won’t flower in the first year after renewal pruning. This aggressive pruning method should not be used on boxwoods and narrow-leaf evergreens, such as junipers, rosemary, arborvitae, cypress, and pines, as these plants do not recover from pruning that removes their foliage.

Although renewal pruning appears brutal, there’s intentionality in the cuts. In the case of the apparently dead gardenias, I used sharp, by-pass hand pruners to cut back small branches (less than in inch in diameter) on a slight angle just in front of a node where a bud would grow. Larger branches (up to two inches in diameter) required loppers. If I didn’t see living tissue – stems showing moist, bright wood with a rim of green just under the bark – I cut back to the next node.

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Prune Safely -Wear protective equipment when pruning: Gloves to protect your hands and long sleeves and safety glasses to protect your arms and eyes from scratches when you reach and lean in to make cuts.

Two gardenia stems of similar size. The left has healthy, moist wood with a green rim. The other has darkened wood and no green tissue.
The living stem on the left shows moist, bright wood and a green rim under the bark. The dead stem on the right has dry, darkened wood and no green tissue under the bark. Photo by H. N. Kolich, UGA Extension.

I eventually found green tissue on most branches, indicating that perhaps only the tops of the plants were dead. Hopefully, the root systems retain enough spark to push out new leaves and stems now that the dead upper canopy and the completely dead branches are gone.

As I pruned my way through the hedge, I tried to maintain a uniform height along the line and a slightly rounded shape to the individual shrubs. I also took the opportunity to remove ground level branches and reduce excess branching. Providing improved air circulation under and through the shrubs will help reduce fungal diseases.

A gardenia bush severely pruned back after a late season freeze.
After cutting back to living tissue, the shrubs stand 6-12 inches above the ground. New leaf and stem buds should form within 2-3 weeks after mid-March renewal pruning. Photo by H. N. Kolich, UGA Extension.

Renewal pruning should produce new bud swell within 2-3 weeks and good growth by summer, but it’s still possible the root system is damaged or too weak to recover. If replacing the plants does turn out to be necessary, select plants that are suited to the existing conditions of the planting site (sun, shade, soil conditions, wind exposure, etc.), will provide the desired function in the landscape (screening plant, evergreen foundation planting), and will naturally maintain a size or shape suitable for the space.

UGA Extension has a couple of on-line publications that provide excellent information to guide plant selection for various growing environments and aesthetic attributes. Landscape Plants for Georgia, UGA Extension Bulletin 625, covers Georgia-hardy landscape plants from ground covers to large trees. Native Plants for Georgia Part 1, UGA Extension Bulletin 987, focuses on native trees, shrubs, and woody vines. Click on the “View PDF” button for a reader-friendly version.