Freeze Recovery Advice

Josh McGill freeze

Winter Storm Elliott brought freezing temperatures to the cold-hardy region Dec. 24–28, 2022, resulting in significant injury to citrus. Danielle Williams, Muhammad Adnan Shahid and Mujahid Hussain, all with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), provided storm recovery advice in a recent edition of the Cold Hardy Citrus Connection newsletter. Following is a summary of their recommendations.

Freeze-damaged wood with living tissue (left) vs. freeze-damaged wood with dead tissue (right)

Since it’s difficult to truly determine the extent of the damage after a freeze, growers are still in the “wait and see” period. Leaves shedding a few days after the freeze is a positive sign as this indicates the wood is likely not damaged or dead, whereas leaf retention usually indicates dead wood. In general, green tissue indicates live wood, while brown tissue indicates dead wood.

By now, growers may be seeing small new growth on trees, depending on variety. This new growth developing on freeze-damaged trees will often dieback later as the wood behind the new growth dies. This may continue through May/June. Therefore, proper time should be given for dieback to cease and for new healthy growth to fully expand before pruning. When it’s time to prune, cut into live wood, just below dead wood.

It’s best to also wait until spring before fertilizing. Fertilizer should be applied frequently, but the rates should be reduced, depending on the degree of damage. Trees that are severely damaged (50% to 60% wood loss or more) will most likely not produce fruit this season, and their rate of fertilizer should be lowered to promote a slow recovery. Trees with 10% to 15% wood loss should receive a regular fertilizer program as fruit will be expected.

Trees with significant damage may show signs of nutrient deficiency because the leaves require nutrients to regenerate large amounts of new growth necessary to replace lost foliage. Therefore, foliar applications of micronutrients will be important for new growth.

Trees will require less water due to leaf loss and transpiration being reduced. Therefore, the amount supplied to the tree should be reduced. Over-irrigating in the winter can induce new growth which could be damaged by a later freeze. However, trees with new growth should not be water stressed.

An effective pest management plan to reduce stress from weeds, insects and disease will be important for recovery. Weeds will compete heavily with trees for nutrients, water and light, and proper management should be implemented. Fungicide applications in the spring to help protect infection of new flushes and next year’s crop will be essential.

To learn more about citrus freeze recovery, see Freeze Damage Symptoms and Recovery for Citrus and attend the Citrus Health Forum on Feb. 23 at the UF/IFAS North Florida Research and Education Center.

Source: UF/IFAS

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