Greenscape Gardens Green Blog

CARE FOR PLANTS AFFECTED BY FREEZE DAMAGE

The freezing temperatures which occurred this past weekend has wreaked havoc on the plants in the St. Louis area. It's impossible to predict how much damage has occurred in your particular neighborhood. Some areas were hit harder than others because of micro-climates and wind breaks. Areas that had sustained freezing periods for longer times will suffer more than short periods of freeze. Not all damage will be obvious as soon as the temperatures warm up; it may take several days before the full extent of the damage to the plants become obvious.

Many plants had lush, new growth and this growth will be the most heavily damaged. All damaged plant tissue should be removed because diseases can start in the damaged tissue and move into the new growth as it emerges. Most freeze-damaged plants would benefit from a light amount of fertilizer and proper watering to help feed the plants and speed the recovery process. The best way to treat the plants will depend on the variety; here are some recommendations for the most common plants.

Shade and Ornamental Trees

The best treatment for all trees is to strip (by hand) the damaged leaves and young twigs off the plants. All trees have secondary buds and these will begin flushing out once the damaged leaves and twigs are removed.

Fruit trees

Most fruit trees bloom in the spring. If the trees haven't bloomed yet, then the blooms are probably damaged. For trees that have already bloomed, then the flowers were probably pollinated, but the young fruit was probably damaged and will most likely fall off the trees. All of the damaged leaves, twigs, flower buds and fruit should be stripped for the trees.

Landscape Shrubs

Slow growing shrub varieties such as althea, lilacs, and viburnum should have the damaged new growth stripped off. Try not to cut these plants back because it will take too long for the plant to recover from being cut back before new growth will begin again.

Fast growing shrub varieties such as Crapemyrtle, hydrangea, spirea and weigelia should have the damaged new growth cut off to speed up the recovery process. These plants will respond quickly to shearing and begin new growth rapidly.

Flowering Shrubs

Besides the lush, emerging new growth, the next part of the plants that is most susceptible to freeze damage are the flower buds.

Spring blooming shrubs that had flower buds present will probably lose the flower buds and won't bloom later this spring (or at least, very weakly). If the flower buds are black, then they are dead and need to be removed. If the flower buds are still green, then they should be left on the plants because they could still bloom. Even if the flower buds open the petals should show some discoloration from the freezing weather.

Summer blooming shrubs probably have not begun forming the flower buds yet, so their blooming should not be affected. Some shrubs bloom in the spring and re-bloom throughout the season, such as the Endless Summer Hydrangea, Blushing Bride Hydrangea, Abelia and Weigela. These varieties may lose their flower buds this spring, but form more buds and bloom later this spring and early summer.

Conifer

Most conifer should have minimal damage, if any. Conifer that had new growth just emerging, such as spruce and yews, will probably drop the needles and begin re-growth in several weeks. If this happens, then any twigs that are left after the needles have dropped, should be cut back to the healthy green part of the branches.

Roses

Most shrub roses held up well through the freezing weather, but new growth may have been damaged. If so, cut off the damaged tissue and the plants will regrow very quickly.

Ornamental grasses

The new flush of most ornamental grasses will probably need to be cut off. The growing point for ornamental grasses is down in the crown (at or below the soil surface) and probably wasn't damaged, so once the damaged tissue is removed, the plants will begin new growth very quickly.

Perennials

Like ornamental grasses, the growing point for most of the perennials is in the crown of the plant, so once the damaged tissue is removed the plants should recover quickly.

Annuals and Tropicals

All annuals and tropical should have been moved inside heated areas. If not, then the plants are probably dead or have severe dieback.

Compounding the problems from last weekend, the weather man is once again predicting freezing weather for the St. Louis area this coming weekend. Hopefully, they are wrong and additional plant damage will not occur.

IT REALLY IS SPRING ........ WEATHER OR NOT