Cold Weather Plant Care

If the weather suddenly turns cold, early-flowering and tender plants may need special protection to avoid damage by freezing temperatures. There are several ways you can provide winter protection, including 1) mulching; 2) covering the plants; 3) moving them; or 4) taking advantage of a light snow covering.

MULCHING This is one of the best ways to protect plant roots. Bark, straw, sawdust, peat moss, leaves and even grass clippings are the most common mulching materials. Remove the weeds (if possible) before applying the mulch. As a rule the mulch should be about 2 inches in depth. Keep the mulch an inch or two away from the trunk or main stem of the trees and shrubs. Again, there are exceptions, such as roses and cane berries, where the mulch is actually mounded over the canes. Then when spring arrives, after all danger of frost has passed, these mulching materials should be pulled away.

Occasionally check through the mulching material, (about once a month) to be sure that moisture is getting to the soil below. This is especially important for plants that are situated under tall evergreens where the soil is likely to dry out. It is important to note, that the combination of dry soil and cold temperatures can cause serious freeze damage to garden trees and shrubs.

COVERING This is one of the most effective ways of protecting the foliage of evergreen shrubs. Rhododendrons, camellias, azaleas and early flowering plants will often benefit from being covered with some type of fleece or material during extremely cold weather.

Start by placing three or four stakes around the plant being protected. Next drape some plant fleese over the stakes, being careful that the fleece does not come in contact and freeze on the leaves. The fleece should only be left in place during the cold spell. As soon as the weather moderates or it begins to rain, remove the covering completely. However, leave the stakes in case it gets cold again.

LIGHT SNOW COVER Mother Nature actually provides the best blanket of protection in the form of a light snow. Up to two or three inches of snow not only insulates the ground around your plants it also provides a blanket of protection over the leaves.

On the other hand, it should be noted, that a heavy wet snow could cause considerable damage. As it tends to place too much weight on the leaves and branches, often causing them to break. And, in some cases even causing trees to break off. So if the snowfall is wet and heavy, you should make it a point to shake-off the excess snow before any damage occurs. Try to do this carefully so some snow remains as a winter protection.

SPECIAL CARE

ROSES: Mound mulch up over the base of rose canes, to a depth of 8 to 12 inches. Bark, sawdust and straw are among the best materials to use for this job. Pull the mulch material away in early spring. A frame of rabbit or chicken wire can be made around tree roses, and then filled with straw to completely protect the stem and upper parts of the tree rose. Most climbing roses are very hardy and seldom need covering protection.

CONTAINERS: One of the easiest ways to give them winter protection is to simply move them into a greenhouse, porch or conservatory over winter

If the planted container is too large to move inside, you can mulch around the sides of the container. Simply mound bark or sawdust up around the sides of the pot, or wrap the container with blankets or packing. (Either way, this is not attractive, so even if you have to borrow a hand-truck, it's best to move the large container inside during coldest weather.)

CANE BERRIES: Berries like raspberries seldom need winter protection, however if you live in a very cold spot, you can mound 10 to 12 inches of mulch around the base of the canes. Straw is excellent for this, then in springtime use the straw as mulch between the rows.

TENDER PERENNIALS: Plants like chrysanthemums, hardy fuchsias, penstemons; and other tender plants can be covered with only about one inch of straw during a cold winter. (In a mild winter, this is usually not necessary.)

HALF-HARDY SUMMER ANNUALS: Stock and snapdragons are only two prime examples of annuals that will sometime become perennials and winter-over if given a little mulching attention. Straw, bark or sawdust are the best materials to use for mulching over these plants. Use only about one inch of mulch.

HALF-HARDY SHRUBS & VINES: This group would include: Bougainvillea, Euryops (Yellow daisies), Hibiscus, Gardenias, Mandevilla, Citrus, etc. In the Pacific Northwest and other areas where the temperatures dip below freezing, these plants should be treated as indoor houseplants over-winter.

OTHER ANNUALS: New Guinea impatiens, fibrous begonias (Wax Begonias), coleus and Abulton (flowering Maple) are just a few of the summer annuals that you can pot-up and bring into the home to use as houseplants. Then next spring, after all danger of frost is over, these plants could be once again planted outside.

FUCHSIAS & BEGONIAS must-be taken indoors before the first heavy frost or they are apt to rot and die. Most varieties of fuchsias will tolerate temperatures down to about –2 TO -3 degrees before serious damage is done. However, don't take a chance. Start preparing them for winter before the first heavy frost.

To winter begonias, simply take them indoors, placing them in a cool, well-ventilated room. Begin withholding water from them and the foliage will die back. Within a few weeks you can easily remove the stem and leaves without damage to the tuber. Next, remove the tuber from the soil, clean it off, dust it with a complete soil dust and store it on top of dry peat moss until it is ready to be restarted early next year.

In order to over winter non-hardy fuchsias; the first job is to ensure that all the plants are devoid of leaves. Ideally, they should begin to fall off naturally on their first encounter with exceptionally cold weather, but if they don’t, then there’s no alternative but to remove them by hand. The reason to do this is to reduce the possibility of encouraging any fungal disease due to rotting vegetation. Plants may be sprayed with a fungicide whilst they are dormant. This is best done early in the day when the weather is mild so that the greenhouse may be left open to allow it to dry out.

It is vital not to apply too much water to the compost that accommodates a sleeping fuchsia. Unfortunately, the demise of many fuchsias being protected during the winter is mainly due to over watering. The ideal condition for dormant plants is to retain the compost just moist throughout the winter period.
On no account must the compost be allowed
to become dust dry.

Whatever type of heating is used, the temperature within the greenhouse or any other form of shelter you happen to choose for over wintering your plants, should be maintained just a few degrees above freezing. If it rises too high, plants will start into premature growth. The shorter light hours during the winter and too high a temperature will encourage them to develop very weak and drawn shoots. This must be avoided because it will render the resultant plants absolutely useless. It is not necessary to keep fuchsias actively growing during this time of the year, but if you do, a temperature between 5°C (41°F) and 10°C (50°F) should be ideal to just keep them ‘ticking over’.

Be warned, unless you have many plants within the confine of the greenhouse to make it worth your while, this could result in expensive heating bills if there is a severe winter.
It is most essential that the door of the greenhouse should be left open periodically throughout the winter to allow air to circulate, but only if the days are mild for the time of the year and dry. Fresh air is a must for hibernating fuchsia plants.

An economical way to prevent the cold from entering (or the warm air escaping), is to double glaze the greenhouse by attaching sheets of bubble plastic on the inside of the structure. Bubble plastic, as the name implies, has air trapped within ‘pockets’ attached to one side of the sheet. The sheets are manufactured with different size bubbles, thus giving varying degrees of insulation. As a general rule, the larger the bubbles, the greater the insulation qualities.

An alternative method is to remove all the leaves and then prune back each branch by approximately one third. Insulate the plants separately with newspaper or some other similar material and then lay them horizontally (whilst still in their pot) in a strong cardboard box and secure the lid. These are to be stored in a place where the temperature is just a few degrees above freezing. Periodically you will need to inspect them to ensure that the compost does not dry out completely. The same rule applies as before, maintain the compost just moist. It is recommended to open the box occasionally on mild days to allow the fresh air to come into contact with the dormant plants. This is to prevent the possibility of encouraging botrytis.

Whatever method you select to winter your tender plants, be sure they do not dry out over the winter. Also remember that they should not get too wet or their roots will rot and the plants will die. Adopt a regular watering and feeding schedule to ensure success.