If you have freeze-damaged plants, is there anything you can do for them? While you cannot save plants that have died from the cold, there are things you can do for those plants that lived but are just damaged. Some of these steps call for immediate action, while others require patience.
For damaged plants that are herbaceous—plants that do not have woody stems—you want to remove any dead leaves. This should be done as soon as possible since these dead leaves may promote disease, especially if they are touching the base of the plant.
For plants with woody stems, you need to be patient. Instead of pruning off what you feel may be dead wood immediately, you want to give your plants time to grow again. This way, you can see where your plants are sprouting and can determine which parts need removing. Watering is one thing you can do after the immediate danger of continued freezes is over. The water will not help the plant to grow, but may thaw any ice which has formed in the soil.
You may find you have some damage on your trees. If you have a newly planted tree, its roots may have suffered, while a tree that has been in the ground for some time may only have damage to the ends of its stems. You will need to wait until spring to assess each tree individually. Follow the advice for woody-stemmed plants and wait until new growth appears to determine where damage has occurred. Trees may take more time to bud out than shrubs, and even one side or a portion of the tree may take more time than the rest of it, so be very patient with large plants. The worst damage that may occur on trees or woody plants is cracks in the trunk. If the crack extends to the base, prepare yourself for the possibility you may lose the plant entirely.
For vines that you feel have frozen, wait until the weather warms then cut the partially dead stems to new growth, as low as around six inches above the ground. Patience will be required since it may take months or possibly years for your vine to once again grow to its prior length.
Lastly, lawns may have suffered damage, too. It is best not to walk on grass that is frozen, so wait until temperatures warm before going out to check on your lawn. Although you may immediately see damage, again, this calls for patience. You can remove the damaged areas and replace with sod or plugs in the spring. Remember, many grasses turn brown in the winter naturally in their dormant state, so things may not be as bad as it initially looks. Also, the fact that these freezes came late in the winter may have helped insulate your lawn against damage since a longer blade length would help freeze damage from occurring.
The one thing that you do not want to do whether you are talking about lawns, shrubs, trees, perennials, or vines is to fertilize. Fertilizing now would only promote quick growth which might attract pests and would be more susceptible to damage from future frosts later in the season. Let your plants rest now and later you may give them the appropriate amount and type of fertilization at the proper time.
What makes these latest freezes so damaging, besides the extremely low temperatures, is that the plants may have already been putting on new growth. The good thing is that by the middle of April, the possibility of another freeze should just be a memory.