EXTENSION CONNECTION: Treating cold-injured King Sago plants

Published: Monday, June 30, 2014 at 02:29 PM.

Many North Florida landscapes' King Sago plants still look sad following cold injury from our recent winter.

Want to know what to do with sagos not fully recovered?

Bob Bayer, a University of Florida-Okaloosa County Extension Master Gardener, and I can help!

Two scenarios

In many cases, all the cold-injured sagos' fronds, or leaves, turned brown, requiring removal.

Many King Sagos responded well to the dead-frond removal and to being fertilized. May and June's higher temperatures have allowed slow recovery in many cold-damaged sagos. They now are displaying new, feathery, dark-green fronds, which will harden, giving the plants their characteristic appearance.

Other sagos have not been as fortunate.

Cones' energy source

Sago plants are either male or female. Some male sagos now produce cones instead of new fronds. This resembles a yellow to tan pine cone up to 2 feet long.

Cone production wouldn't be a problem if the fronds had not been lost to cold damage. Without green fronds to produce food for the plant (through photosynthesis), the cones draw energy for growth from stored food (sugars) in the trunk.

Also, heavy rains have leeched away many nutrients that were in the soil.

As a result, these weak sago plants are attempting to propagate their species before they possibly die.

Preventing fungal infection

In addition to producing cones, some sagos produce off shoots (pups), a vegetative means of propagation. This is a draw of energy from the parent plant without replacement. There is no guarantee that removing these pups will ensure the parent's survival.

Cone removal will decrease the plant's stress, but it also creates an open wound, which subjects the plant to possible fungal infection. Snapping off the cone will not hurt the plant. But after removing the cone, you should treat the resulting wound with a copper-based fungicide.

Always follow label directions when using any pesticide, including fungicides.

Producing new fronds

Older, mature female sago plants will eventually produce a tan reproductive structure that somewhat resembles a flattened basketball or cabbage.

You'll see walnut sized, orange-red seed as this structure slowly opens. Removing the seeds as they develop provides more energy for frond production on the cold-injured, stressed sagos.

But do not remove the female structure; this can cause permanent damage and the plant's possible death. The resulting wound would be too large to treat.

Use a complete fertilizer containing about 18 percent nitrogen to encourage new frond production.

Larry Williams is an agent at the University of Florida's Extension office in Crestview.

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