In the Garden Articles

Gardeners May Find This Cold Comfort

by Joan S. Bolton

Last month's frost and freezing temperatures may have wiped out more than a few plants in your garden.

But the deep cold helped others, too.

Deciduous fruit trees top the list of those most likely to have benefited. Grapes, roses and occasional Eastern temperamentals, such as lilacs, peonies and deciduous clematis, got a boost. And the freeze knocked out pests that might have been lingering through winter, although the cold didn't eliminate them completely.

Winter Chill

Most deciduous fruit-bearing plants actually depend on cold weather in order for their dormant leaf buds and flowers to emerge properly in spring. Deciduous fruit trees -- including apples, apricots, peaches, pears and plums -- typically require 600 to 800 hours of winter chill. That's 600 to 800 hours of temperatures dropping below 45° from November 1 through March 30.

The mildest neighborhoods on the Central Coast rarely get more than 300 chill hours during winter. So the usual advice is to seek low-chill varieties for a reasonable crop.

But plenty of local gardens contain fruit trees of questionable heritage. Regardless of their chill requirements, this year's knuckle-baring cold should have kicked every one -- low-chill or not -- into high gear.

"With a good freeze, what happens is, it tightens up the bloom. The bloom comes out at the same time. You get the set, the bees. It's good for pollination. Everybody's there. All the blooms are out. So you get a nice fruit set, or a better fruit set," said Frank Laemmlen, an emeritus farm advisor for University of California Cooperative extension and Times Coastal Gardener columnist.

Added Guy Tingos, Santa Barbara County Deputy Agricultural Commissioner, "We're usually limited by the varieties we can grow here. The stone fruits, the roses, the apples. They like a certain chill factor. This is going to help a lot. I think they're loving it."

In my garden, the frost nipped a few early buds and flowers on my low-chill Dorsett Golden apple tree. But most of the flowering spurs had not begun to swell.

Overall, Tingos said, the timing was good.

"If we'd had a really cold stretch, there could have been some damage to buds. But most of the stuff was just starting. If the flowers had been out, they'd be much more sensitive. There may be some damage to opening buds. But I think that's minimum, and just in the coldest areas."

Other edibles survived relatively unscathed.

Asparagus was still a few weeks away from pushing up its first spears, while its tuberous roots were well-protected in the ground. Artichokes and low-growing strawberry plants may have lost a few leaves or early flowers, but suffered no permanent damage.

The freeze also sent roses and Bermuda lawns into deeper dormancy than usual.

"Roses in this area never really quit growing. In my yard, they really did stop this year," Laemmlen said. "The process of pruning was less traumatic, because I wasn't pruning anything. I pruned after the freeze. It killed any leaves that were out there, singed them pretty good. Any buds that were out there, were flat out roasted."

As a result, your first roses may bloom a little later than usual, but the overall bloom cycles shouldn't be affected.

As for Bermuda grass, it will likely take longer to green up in spring.

Pests and Other Insects

Many pests suffered, either directly from the cold or from the loss of plants that they were feeding on, Tingos said. "Nothing was wiped out. When the plants recover, the pests will recover. But this will definitely slow them down for a while."

Giant whitefly took a particularly hard hit, given that its favorite host plants include hibiscus, citrus and bananas, many of which were beat back by the frost.

Strawberry mites, aphids, mealy bugs and worms died, too, Laemmlen said.

Unfortunately, beneficial insects, such as green lacewings, parasitic wasps and honeybees, perished as well.

But none of the insects -- good or bad -- is gone for good, Tingos said.

"The pests are too hardy and too well established to completely disappear," he said. "A lot of times after a severe frost or something that damages the plants, the plants will put out a lot of new growth. That of course is more susceptible to aphids and whitefly. Once the plants come out of their setbacks, it's quite likely that the bugs will take off pretty quickly... It's quite possible that populations could get pretty high."

On the other hand, the beneficials are likely to rebound, too, which means "as the populations resurface, they'll still be in balance," Laemmlen said.

The best course of action is to watch for insects over the next few months. Tingos suggests responding quickly against pests -- whether that's by applying chemicals, using insecticidal soap or simply hosing off aphids and whiteflies with a strong jet of water.

"It's just a good idea for people to keep an eye on their plants as they come out of the freeze damage," he said. "Pay some attention so the pests don't get out of control."

Wait to Prune

It's incredibly tempting to cut off dead and dying leaves and branches right away. But the experts advise waiting until your frost-damaged plants resprout before pruning.

"At this point, there is no way to know the extent of the damage," said Guy Tingos, Santa Barbara County Deputy Agricultural Commissioner.

"Wait for the plant to come out of its dormancy... You'll see growth coming out of live tissue. You'll see no growth coming out of dead tissue. The larger the plant or tree, the longer it can take. Making random cuts is not a wise thing to do."

Seeds of Wisdom

Deciduous fruit trees that require little in the way of long, chilly nights are the most reliable producers on the Central Coast. If your trees bloom inconsistently or at odd times of the year, it's likely that they're not low-chill varieties.

Another tell-tale sign is what Frank Laemmlen, emeritus farm advisor, University of California Cooperative extension, and Times Coastal Gardener columnist calls "rat-tail blooms." These are flowers that appear at the branch tips in summer. If the flowers produce any fruit, it's not likely to mature or be edible.