Frost Is Just Too Cool

Frost makes tender foliage ugly fast.

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.

Electric Snow

P81230It was one of the more common types of snow in the Santa Clara Valley in the early 1970s.
In school, we made paper snow by folding paper squares in half and then into thirds (so that they were folded into sixths), and then cutting notches and slices out of them. They unfolded into the prettiest and laciest snowflakes!
In Westgate Mall, snow was blown by small fans about the new models of Singer sewing machines that were magically suspended in big acrylic spheres. We children could not get into the spheres, so were left wondering if the snow within was as cold and wet as we were told it was, and why it was necessary to demonstrate that the new sewing machines were resistant to weather. Our mother did her sewing inside.
We sort of suspected that the snow around the Nativity at Saint Thomas of Canterbury and other local parishes might be artificial because it looked like the stuffing of a pillow, which is something that all children seem to be familiar with. We said nothing about it, just in case our parents were not aware of the potential deception. However, it was rather disturbing to see so much of the same sort of snow at Christmas in the Park in San Jose. At that point, we accepted that either it must be genuine, or that we were committed to just going along with it.
Snow that was sprayed onto Christmas trees was rather interesting. It was neither wet nor cold, and sometimes it wasn’t even white. It could be pastel blue or pink, and was often sparkly with glitter! Wow!
Off in the distance, we could see snow on top of Mount Hamilton. Sometimes it was just on top. Sometimes, it was spread out from left to right, along the ridge. On rare occasion, snow appeared on the ridge of the East Hills, in front of the Diablo Range that Mount Hamilton is part of. We never saw who was up there folding and cutting all that snow, but they must have been VERY busy!
Snow on top of the Santa Cruz Mountains, right behind our part of the Santa Clara Valley, was closer to home, but did not look like much. The greenish blue of the forest was just a lighter hue of blue, with more mottling. It was exciting anyway.
Then, on February 5 in 1976, it actually SNOWED on the floor of the Santa Clara Valley!
It really was as awesome as snow was supposed to be. It was cold. It was wet. It was white. It was fun to wad up and throw at each other. It accumulated just like it would in a blizzard, and got almost an inch deep!
. . . but . . . was it really SNOW?P81230+

Winter Coat

P80117Wire haired terriers know how it works. They wear wiry hair through summer to shade their skin while allowing cooling air circulation. Their softer and fuzzier undercoat that develops in autumn provides better insulation from cold weather through winter.

Beards are not naturally so adaptable, but can be manipulated to function better. Thick beards might insulate and deflect wind through winter. Short beards may not work as well in that regard, but might absorb warmth from sunlight if still darkly colored. As weather gets warmer in spring, beards can simply be removed to optimize cooling air circulation, and eliminate the extra insulation. However, long and gray beards can provide shade without absorbing much warmth from sunlight.

Have you ever noticed that plants that live near foggy coasts or in the lower levels of shady jungles and forests are the darkest green? They want to absorb all the sunlight they can get. Monterey pine, Monterey cypress, coast redwood and the many ferns that live on the ground below them are classic examples.

Plants that live in exposed situations or high elevations are lighter green. Some have glaucous foliage that is shaded gray or blue to reflect a bit of sunlight. Colorado blue spruce, silver leaved mountain gum, century plant and silver sage exemplify this technique. The old man cactus actually shades itself with weirdly elongated spines that resemble gray hair.

English walnut, maple, apple and pear have sensitive bark that would get burned if too exposed during summer. Yet, they are all deciduous and bare through winter. They do not mind, because the intensity of the sunlight through winter is inhibited by the low angle of the sun. By the time the sun is higher in the sky, and the sunlight is more direct (passing through less of the atmosphere at the higher angle), the sensitive bark will be shaded by new foliage.P71019


P71208+K1Yes, we get it too. It took a while, but we finally got it just like most of everyone else in North America and the Northern part of the Norther Hemisphere. It is not much to brag about, but it is enough to melt the big feral pumpkin vine that I wrote about earlier ( ). It has actually been frosting for a few nights. I just got around to getting this picture this morning.

Now that the foliage is melting and collapsing, a leak is now visible in the exposed valve manifold that was obscured in the previous picture. It did not get cold enough to freeze the pipe, so the water was dripping freely. This confirms the earlier theory about where the pumpkin vine was getting water from.

Two pumpkins are also exposed by the collapsing foliage. They were not visible earlier. Unfortunately, they are too under-developed to mature and ripen. A neighbor will likely take them and set them aside on the porch, just in case they are able to finish ripening. It would be nice if they did. The vine certainly put a lot of work into them!P71208+K2P71208+K3

While taking this picture, I was reminded why people who live with cooler weather dislike it so. First of all, and most obviously, it kills things. The season is over for pumpkin vines, which is not a problem. The problem is that so many of the citrus, avocados and other plants from mild climates that we grow so easily here get damaged or killed by frost in other climates.

The second reason to dislike cool weather is that it is too cool, maybe even cold. It is uncomfortable to be out in long enough to walk over and get these pictures of the pumpkin vine and pumpkins. I am glad that it does not get much colder here.