Garden News: Give plants time before pruning

When Mother Nature sent south Louisiana into a deep freeze earlier this month, she played havoc with landscape plants.

Although the results are often obvious, LSU AgCenter horticulturists warn not to be too eager to react.

If you haven’t done any major pruning, they suggest waiting a while.

“Do not prune anything for a week or more after a freeze,” says horticulturist Dan Gill. “It often takes a week or so for all of the damage to become evident.”

Damage on nonwoody tropical plants, such as cannas, elephant ears, birds-of-paradise, begonias, impatiens, philodendron and gingers, may be pruned back to living tissue, especially if the damaged tissue is oozy, mushy, slimy and foul-smelling.

Gill says to remove damaged foliage from banana trees, but don’t cut back the trunks unless you’re sure they’ve been killed.

You can remove dead leaves from woody plants to make them look neater. If you can clearly determine which branches are dead, prune them off.

Azaleas are generally cold hardy, says horticulturist Allen Owings. But you may find some isolated cold damage on certain varieties.

You also can expect to see considerable damage on woody tropical-type plants, such as ixora, cassia, copper plant, plumbago, tibouchina and hibiscus.

Symptoms are often sectional, with some parts of the plant staying green while others are dying. It’s best to wait for new growth in the spring, then prune plants that are still alive to the point where new growth starts.

You can also check underneath the bark of these plants by scratching the bark with a fingernail. Green tissue indicates wood that is alive. Brown, black or tan indicates dead plant tissue.

Patience is the key as we wait to see how our landscapes recover during the next couple months. Spring growth will be a good indication. Wait to prune, if possible.

In the future, plan to move plants, cover plants and mulch plants prior to a severe cold period.

Got a gardening question? Write to GardenNews@agcenter.lsu.edu.