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Frondless King Sago plants

Many King Sago, Cycas revolute, plants in our North Florida landscapes still look sad as a result of cold injury that occurred during our most recent winter.

In today’s article, Bob Bayer, UF/IFAS Extension Master Gardener in Okaloosa County, and I explain what to do with sagos that have not fully recovered.

In many cases all of the fronds (leaves) turned brown, requiring removal, on cold injured sagos. Many King Sagos responded well to the dead frond removal and to being fertilized. Warmer temperatures of May and June have allowed slow recovery in many of the 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. Sago plants are either male or female. Some male sagos are now producing cones instead of new fronds. The cone resembles a yellow to tan-colored pine cone up to 2 feet long. Cone production would not 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 are drawing energy for growth from stored food (sugars) in the trunk. Also, many of the nutrients that were in the soil have leached away by heavy rains. As a result, these sago plants are weak and are attempting to propagate their species before they possibly die.

In addition to producing cones, some sagos are producing off shoots (pups) which is a vegetative means of propagation. Once again this is a draw of energy from the parent plant without replacement. There is no guarantee that removal of these pups will insure survival of the parent. But cone removal will decrease the stress the plant is under. However, cone removal creates an open wound. An open wound subjects the plant to the possibility of fungal infection. Snapping off the cone will not hurt the plant. But following removal of a cone, treat the resulting wound with a copper based fungicide. Always follow label directions when using any pesticide, including fungicides.

Older, mature female sago plants will eventually produce a tan-colored reproductive structure that somewhat resembles a flattened basketball or cabbage. Walnut sized, orange-red seed will be seen as this structure slowly opens. Removal of the seeds as theydevelop will provide more energy for frond production on the cold injured, stressed sagos. But DO NOT remove the female structure as this can cause permanent damage and possible death of the plant and the resulting wound will be too large to treat.

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

Larry Williams, UF/IFAS Extension Agent, Okaloosa County, June 26, 2014

Permanent link to this article: http://okaloosa.ifas.ufl.edu/lng/2014/09/29/frondless-king-sago-plants/