UNITED STATES—Is it too late to warn about frost? After all the rain, the recent and sudden cold weather was quite a surprise. Fortunately, these recent frosts were relatively mild. This sort of weather is probably just enough to start to satisfy plants that require chilling through winter without causing too much damage to too many sensitive plants. So far, only the most sensitive plants, like angels’ trumpet, canna and left-out houseplants show symptoms of frost damage. (Cannas should get cut to the ground at the end of winter anyway).
Doing without all frost sensitive plants would be too limiting. Lemon, avocado, bougainvillea, fuchsia and Australian tree fern would be off limits. Such plants are worth growing, as long as we understand the potential for occasional frost damage. Those that are too big to protect may sometimes need to get pruned for removal of stems that get killed by frost. In milder climates, such damage will be very rare. In cooler spots, damage is more common, and may involve a few tougher plants, like jacaranda.
Smaller plants that are sensitive to frost, such as jade plant, angel wing begonia and the various pelargoniums, can be grown in containers so that they can be moved to sheltered spots before the weather gets too cold for them. The most sensitive sorts need to be moved under a porch roof or eave, or maybe into a garage. More resilient plants may be safe under overhanging trees or against a wall. South or west facing stucco walls radiate a slight bit of warmth at night.
Frost sensitive plants that get too big for containers should be planted in sheltered spots, like below eaves or larger trees. If a severe frost is predicted, young plants can be protected by burlap, paper, trash bags or any convenient sheeting suspended above by stakes. Foliage that touches the sheeting may get frozen, but foliage within should be fine.
Foliage and stems that get damaged by frost should not necessarily get pruned away immediately. Although unsightly, the dead foliage insulates damaged stems below from subsequent frost. Besides, premature pruning can stimulate new growth, which is more sensitive to subsequent frost.
Highlight: hobbit’s pipe
Good old fashioned jade plant has a few interesting cultivars (cultivated varieties) that exhibit variations of color, texture and form. Hobbit’s pipe, Crassula ovata ‘Hobbit’, is similar to classic jade plant in form and color. It is only slightly lighter green, and only a bit shorter. The succulent stems are just as plump and gray. The small and round-topped clusters of pale pink or white flowers that bloom sporadically are just as unimpressive. What is unique about hobbit’s pipe is the weirdly tubular foliage. Each leaf is rolled into a cylinder, with a hollow tip.
Mature plants do not often get much more than two feet tall and broad, although they have the potential to get twice as large. Because they are more sensitive to frost than other jade plants, hobbit’s pipe should be grown in sheltered spots, or pots that can be moved to sheltered spots through the coldest part of winter. Foliage that is too exposed during the warmest weather of summer can get roasted. Hobbit’s pipe can tolerate a slight bit of shade, so can be happy as a houseplant.