Last week, we noticed that a majority of our potted hostas out in retail had significant frost damage. We think the extent of the damage was worsened by the timing on our irrigation system. Sprinklers run from midnight to 6:00 AM, one section at a time, for 30 minutes. Some hostas were worse off than others. The hostas that were given more time to dry off before the coldest hours of the morning fared better than the ones that were watered right before the temperature dipped below freezing. It is important to keep the soil nice and moist when trying to prevent frost damage, but droplets of water on a leaf’s surface is something that should be avoided. Thankfully, the hostas back in our stock houses were still looking great, so operation ‘Hosta Swap’ was put into action. There were some varieties that only had a few leaves showing frost damage, so these were cleaned up by simply removing the damaged leaves. Most everything else needed much more attention. We cut the foliage all the way back on a majority of the hostas and replaced them with healthy ones. In a few weeks, the hostas we cut back will have sent out new leaves and will be ready to return to the sales bench!
The following are some tips to consider when trying to prevent frost damage on any plant:
- Cover the plant. Things often used to cover plants include sheets, blankets, buckets, mulch, leaves, etc. If you are using a sheet or blanket, it is best to use some sort of supporting structure to avoid contact with the foliage.
- Move container plants into the garage or onto the porch.
- Keep the soil moist. A healthy plant is much more likely to survive a hard frost than an unhealthy plant. Keeping your plants well watered before a frost not only ensures you have a happy, healthy plant, but also creates humidity around your plant, which helps buffer a dramatic change in temperature.
- Don’t prune or cut back frost damaged foliage until the danger of another frost has past. Pruning too early can stimulate new growth which is tender and even more susceptible frost damage.