The Cold Hard Truth on Plant Freeze Recovery
If a sudden deep freeze leaves you in the cold, it’s nothing compared to what it may have done to your customers’ shrubs and trees. While prevention is always the best method to protect against frost damage, an unexpected late-spring or early-fall cold snap can leave little or no time to prepare.
Once a freeze hits, the questions become what can be saved and how. Our plant freeze recovery tips will help. We’ll go over how to assess the damage, whether you should water plants after frost and even talk about the need to wait and see what develops.
Determine a Plant’s Condition
The first thing to do with post-frost plants is seeing how they have held up. Shrub and tree damage can be effectively checked a few ways.
- Smaller branches should still be pliable, bendable or springy. If they snap while testing their elasticity (slightly bending the smaller parts of the branch), it’s a sign of damage.
- Leaves that are damaged will drop from the branches naturally if the actual branches remain intact. A branch that holds dead leaves or doesn’t drop them is no good. (An exception to this rule would be certain types of oak trees that hold onto their leaves until the new spring buds push off the old dead leaves. Be sure to know what kind of trees you have.)
- Use the “simple scratch” test. Start scratching at the tip of the branch and continue to move back and forth making small scratches every foot until you find green. The deeper you go to find green the deeper the damage. If green appears early in the process the tree or shrub should survive.
Patiently Wait to See How Much Damage There Really Is
Sometimes, plant frost damage won’t reveal itself right away. Patience is a virtue in assessing the damage. If you can hold up on pruning, you’ll be better off.
As plants leaf back out over the next few weeks, a month or even next spring, you will see how extensive the damage may be. If the tips of a plant have not come back or “re-leafed,” you will be able to determine just how far you need to prune.
Check Sensitive Plants
Plants like Loropetalum, Rosemary, Hawthorns, Wax Leaf Ligustrum and other similar varieties, will probably need to be replaced after a deep freeze. If they were protected from colder winds, or were closer to a house, they still may survive. Give them a few weeks to see how they rebound. If in 30 days, of consistently above 40 degree temps, nothing has happened, then it’s likely time for replacing.
Get the Mush out of there!
Is vegetation mushy and rotting? That’s disease waiting to infect your landscape.
- If foliage is mushy, remove the material as soon as possible. Be sure to only remove the wet and mushy parts.
- Do not remove the whole plant unless it is all mushy. Agave and Aloes could come back from the roots. However, depending on the plant size, this can be a slow process and it might be easier to replace than nurse the plant back.
- In the case of Agave and Aloes, as well as some cactus, it can take a year plus for them to rebound.
- For palms, brown fronds should be removed to help stimulate possible new fronds sprouting from the center of the trunk. It could be eight or more weeks before new fronds emerge. However, waiting is the only way to determine if a plant will rebound.
Know When to Wait
Remember those nice perennials that you planted the past few years? They may or may not be coming back after a hard freeze. A lot of the popular, trendy, new perennials were not made to handle deep hard freezes. Your best practice is to patiently wait to see how much damage did, or did not, occur. Perennials can take their time coming back up in the spring so be sure to be patient. A good guide is to wait to see if anything sprouts up after about 30 days of consistent temperatures above 40.
Replace Lost Plants
Once you’ve determined that a plant is lost, you should replace it as soon as possible so the new one has the most time to grow and flourish. Follow these helpful tips and start replacing lost plants as soon as all chances of more hard deep freezes are past.
- If you are looking at annuals and softer material, you are good by mid-March to early April in warm regions. For colder regions, you may not be able to plant outside until mid-to-late May. Watch the long-range forecast to be sure.
- Start with plants that don’t mind cool lows at night.
- Be sure you’re sourcing planting material that is hardy for your specific growing areas.
- If you are replacing lost product with dormant trees or shrubs you will have a much wider window of lower temps that could be ok.
Be sure to check with your SiteOne nursery associate if you are unsure or have any questions.
Fertilizing Recovering Plants
At the start, access your stressed plant material and make sure everything is hydrated. When it comes to watering plants after frost, remember you will want to water them, not drown them. A moderate amount of water can go a long way. You should also take care to water the soil directly instead of the foliage. This gets more water to the roots and helps the soil retain heat, which provides insulation against future temperature drops.
If your plant is alive and taking water, help it along with some food. There are three things to be sure of before you fertilize plants recovering from frost.
- Be sure that you are past the possibility of another cold snap before you begin to feed your plants. Fertilizer will stimulate your plants to start growing, but another frost during this stimulation can be damaging.
- Stay away from fertilizer that has a very high first number in the formula followed by two very low numbers after, such as 28-3-10 or 24-0-0. These fertilizers are designed to push top growth and can do more damage to an already weak plant.
- Use fertilizers that offer a mild blend/balanced formula like LESCO Granular L&O 14-14-14. There is a lower chance of burning and the balanced formula will address your plants’ overall needs. You’ll also want to stick with a granular formula over a liquid feed. This will promote an extended release that lasts longer and will deliver nutrients in a more balanced way.
Nothing can completely undo the damage plants and shrubs faced in the freeze. But our nursery branches are poised to help you with questions and replacements. Visit SiteOne.com to start sourcing new plant material or visit your local branch for in-person assistance.