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Don’t rush to judgment on freeze damage

After a deep freeze, daffodils may bend over because frozen tissue is too heavy for the flower stem to stand up normally
After a deep freeze, daffodils may bend over because frozen tissue is too heavy for the flower stem to stand up normally File Photo

Until this week, it seemed like we had been enjoying spring since the second week of January. So good was the weather that the word “winter” fell into disuse, only to be reclaimed now just as spring’s beauty is out in full glory.

So here we are, taking stock of the freeze damage that was done to open blooms on camellias, azaleas and other flowers as well as tender new growth on trees, shrubs, hydrangeas and hostas.

The first thing to remember is avoid a rush to judgment. The lowest temperature and the duration of freezing can vary within cities and counties, urban and rural areas, uplands and lowlands.

The most vulnerable plants in freezing weather are tropical ones, but those are mainly vegetables such tomatoes, and most summer bedding flowers that we have not yet planted.

But hardy plants that are with us all year can also be vulnerable, particularly now with tender new growth emerging rapidly. A hard frost of about 28 degrees and below will freeze the water in a plant’s cells, damaging the cell walls and causing dehydration. The damage continues when the morning sun hits the frozen tissue, causing it to thaw too fast.

For example, young foliage and stems on hydrangeas are particularly susceptible because they are still tender, and flowers are quite susceptible to freeze damage because of their generally delicate plant tissue. Young hostas leaves are also quite succulent and thus vulnerable to freezing.

Alarmed as you may be by the weather reports this week, use caution in dealing with the supposed damage, though some of it may show up right away. The exceptions are daffodil blooms, bending over because water froze in the tissue and weighed them down.

Opening buds, such as camellias, tend to brown rapidly after freezing. Pick them off the plant if it pleases you. But buds still tight tend to escape damage since they have less water in them to freeze.

But you should not rush to begin cutting back or removing plants you think were wrecked by the freeze. Give them some days to show evidence of brown or blackened leaves and stems.

Even seeing that, it could be wise to delay cutting back, as stems could still be capable of putting out fresh growth in coming weeks, even though the initial leafing out was badly damaged. Once the weather is settled – and that could be April – you can evaluate and see what portion requires pruning.

This is not the first time deep freeze has threatened spring flowers and new leaves. Though damage to flowers and flower buds is disappointing, most gardeners rejoice when a plant shows signs of life with fresh growth in coming weeks. That is something to look forward to.

Ask Nancy

Q. My pansies, which looked great all winter, now aren’t so good. I don’t think their season is over.

A. It is not over. Spend a bit of time deadheading spent blooms, then give a dose of fertilizer for flowers at the rate directed on the package. They should perk up and look good until the heat hits in late spring or early summer.