Flora in the deep-freeze

Now is a good time to clean up garden damage from recent wintry weather, and prepare for more

Icy greens by Janet B. Carson for HomeStyle
Icy greens by Janet B. Carson for HomeStyle

We had our first taste of winter weather before the official start of winter. Almost everyone in the state saw snow, ice or sleet recently, and we all have had much lower temperatures than we are used to in December.

Today is the winter solstice, and we can only guess what more is in store. Gardeners need to take stock of what’s happened in our yards now that we have defrosted, and do damage control where needed; but we also need to be prepared if more bad weather comes our way.

WEIGHT LOADS

Heavy accumulations of ice and snow can cause limbs to bend and break. If limbs do break off, cleanup should be done as soon as damage is noticed. But don’t do anything more than cutting off broken branches.

Corrective pruning to reshape or restructure should wait until spring, when all potential damage is done. Horticulturists don’t recommend pruning plants in the fall or early winter. Pruned plants will be more exposed to low temperatures without the buffer provided by lots of branches.

But jagged, dangling limbs, if left unpruned, can break off, creating larger wounds; and when they fall, they can land on underlying plants. So do minimal pruning, just enough to take off broken limbs.

BOWED, NOT BROKEN

Some branches that are bending could return to an upright position on their own.

But since last year’s heavy snow in central Arkansas, you can still see some sagging limbs because the snow stayed on them for so long. You can prop them up, but be sure that whatever you use to stake them is not going to cut into or damage the wood. Wrapping the ties or padding the support with a piece of flexible hose or other soft tubing can provide protection. When staking, don’t tie it so tight that there is no room for natural movement.

If you see burned foliage now on any of your evergreen shrubs, ignore it for the rest of the winter. It may not be the most attractive thing to look at, but it will serve as extra protection for the plant for the remainder of the winter.Wait until late February to early April to begin corrective pruning - as new growth is beginning.

The same holds true if you think you have dead branches due to low temperatures. You really can’t be 100 percent certain now that a branch is dead, so wait until winter is over; allow the plants a chance to begin new growth and then see what needs to be removed or reshaped.

CHECK THE FORECAST

This time we had ample warning and time to prepare for the huge drop in temperature. We went from 70 degrees to 20 degrees or less in a few days. People were wearing shorts on Wednesday and long underwear on Friday. While such abrupt change is tough enough on us, we can at least go inside, crank up the heat and wear more clothes.

Meanwhile, our plants are just there. They can’t seek shelter.

Before a hard freeze, make sure plants in containers have ample water. Soil dries in containers much more quickly than it does in the ground.

If conditions have been dry and a hard freeze is in the forecast, water recently planted trees or shrubs and winter annuals before temperatures drop below freezing. Ample moisture within the plants can protect them from some damage. Moisture in the foliage and stems serves as a buffer. If a plant is dry and wilted, it is more likely to be damaged by freezing.

Mulch your plants, especially those that are only moderately winter hardy. Now that everything is good and dormant, a little extra protection of leaves can help them get through the rest of the winter (if they aren’t already damaged).

DEALING WITH SNOW

If we get only snow, you can remove it gently using a broom or rake from the underside of the plant to reduce the weight load. Pay attention, though, to temperatures. If it is well below freezing and your branches are frozen or covered in ice, don’t touch the plants.

Frozen plants are brittle and limbs can snap off easily. Wait for the limbs to defrost before trying to remove any snow.

Plants are typically most susceptible to damage during their transition periods - going into dormancy in the fall or emerging into new growth in the spring. Once dormant, they basically are like animals hibernating. They are conserving their resources and not actively growing.

Some plants are more tolerant of cold than others. Mahonias, hellebores and winter honeysuckle all bloom in the winter and can take a freeze and keep on blooming.

EASILY CONFUSED

Some tender plants begin to break dormancy more readily than others. Big leaf hydrangeas and tulip magnolias are plants that can begin to show signs of life if we have a couple of weeks of mild weather in the winter. They get confused and start growing. Then when a new cold snap comes, the new shoots will be zapped.

Many gardeners in Northwest Arkansas rarely see blooms on big leaf hydrangeas(those that have the large pink or blue flowers). These hydrangeas set buds in late summer to fall, and if they are frozen back, there goes your flowering for that season.

If their spring growth begins from the soil line and not from the top of the old plant, that means the plants were damaged.

COVERS

To protect tender plants, you can cover them, but keep in mind that most coverings give you only a few degrees of protection.

Large cardboard boxes can be inverted over a plant and will help tremendously, even for a few weeks.

Sheets and frost blankets will give you some help, but if it is raining or wet, the weight of the coverings can cause new problems. That is why the box works better - no weight on the plant. So if you are using a cloth cover, consider propping it on some type of support. Not only will that prevent a weight problem, it can also give you protected air space around the plants, which may help a bit.

Avoid using plastic in contact with your plants. Sun shining through plastic generates heat and can cause even more extremes in freezing and thawing, so if you do use any type of plastic, it must be vented on sunny days.

SEASON EXTENDERS

In the vegetable garden,many gardeners are using season extenders to garden year-round. There are many options available. You can get cover kits designed to fit atop raised beds to create a high tunnel.

Basically an unheated greenhouse, a high tunnel can heat up tremendously during sunny days, even if temperatures are low. If the cover material isn’t porous, some type of monitoring and ventilation will be needed.

Extra layers of leaves or a wire frame placed around the plant and then covered adds protection. You can’t exclude light all winter and expect to grow vegetables or winter annuals, but most plants will tolerate several days to a week of being covered; and dormant shrubs can go several weeks without sunlight.

Everyone has seen gardeners using old milk cartons or soda bottles inverted over tender plants to protect them in the early spring, but that wouldn’t work all winter long.

We can all hope that the early December storm was an anomaly not to be repeated for the remainder of the season, but if not, it is good to be prepared for what could happen, and then know how to deal with it once it does occur. Stay warm!

Janet Carson is a horticulture specialist for the University of Arkansas Cooperative Extension Service.

HomeStyle, Pages 33 on 12/21/2013

Upcoming Events