Citrus trees per IFAS.
The type of care needed for citrus trees that have been freeze injured will be determined by a number of factors, including the time of year at which the freeze occurs, the overall condition of trees at the time of injury, and the weather conditions immediately following injury. Twigs and branches may continue to die for a period of several months to a couple of years following a severe breeze. Therefore, making it impossible to determine the full extent of the injury. Citrus trees on which twigs and branches have been killed by cold should receive extra care during the following growing season.
- Pruning – No attempt should be made to prune or even assess freeze damage until the new spring flush gets fully expanded and mature. In early spring, freeze-damaged trees often produce new growth that soon dies back. Early pruning does not promote recovery and delaying pruning to the proper time will save money. It is advisable to remove heavy brush from the grove immediately after the pruning operation.
- Fertilization– Should be reduced until the trees are back to their original canopy size and foliage density. Fertilizer should be applied more frequently, but rates should be reduced in proportion to the amount of tree damage and to the expected crop load. Foliar sprays of micronutrients will be beneficial, due to the nutrient deficiency symptoms that are intensified in freeze-damaged trees. Leaves require nutrients in order to regenerate large amounts of growth necessary to replace lost foliage.
- Irrigation– When leaves are lost, transpiration from the tree canopy is greatly reduced. Therefore, the tree will require less water, and thus the amount of water supplied to the tree should be reduced. Over-irrigation in the winter following a cold injury should be avoided, because it may induce new vegetative growth which could be damaged by subsequent freezes.
- Weed and Disease Control– To ensure rapid recovery from freeze damage, an effective weed control program should be implemented. Weeds will compete heavily with the trees for available water, nutrients, and light. Fungicide applications for greasy spot control after a freeze in May and July are essential. Even on non-fruiting trees, one or two fungicide applications should be made to help prevent infection of new flushes and of next year’s crop.
Hydrangeas
From https://rootingforblooms.com/how-to-help-your-hydrangea-recover-from-damage-due-to-frost-and-cold/
Wait On Warm Weather
If you’ve found damage to your Hydrangeas from the cold weather, the time to act is not the next day or even the next week. The weather should be consistently warm before you start working, as you don’t want to prune your plants right before another freeze starts. This could expose the new parts of the plant to further frost damage, causing the issue to worsen.
Also, time will repair some minor damage on its own. If your Hydrangea has been damaged by frost or cold, wait a few weeks before you move on to pruning back the dead and dying foliage and stems.
Prune Back Frost Damaged Growth
The next step is to prune the plant in the right spots. You should prune all unhealthy stems, leaves, and blooms back to the portion of the plant that looks healthy. Look for new growth or leaves and trim back to just before those areas.
Remember to time this effort when you’re confident that the weather will stay warm for a while. Pruning will drain much of the plant’s energy. It takes time for the plant to recover after you prune its spots. Pruning while it is warm ensures it will recover well.
