Citrus trees are evergreen, not deciduous, and never go fully dormant. As a result, they cannot withstand extremely low temperatures as well as deciduous trees, which are better prepared to handle cold weather.
I thought I had followed good preventive measures for my own trees by covering them with tarps and watering them deeply before the first freeze, but they still suffered significant damage. With near perfect hindsight, I realize that I should also have strung the trees with lights of at least 15watts to provide a little warmth.
After a brief mourning period, it was time to move on. The old English proverb that “necessity is the mother of invention” came to mind as I surveyed the ripe fruit on the trees.
A quick Internet search revealed that citrus juice can be canned and the process is easy. I already had canning jars and lids, a water-bath canner and a juicer so I was ready to go. I sterilized the jars and lids, squeezed dozens of lemons and limes and then heated the juice to 190°F for five minutes. I poured the hot juice into the sterilized jars, sealed the jars with lids and bands and processed them in the boiling- water bath for 15 minutes. Now I have enough canned lemon and lime juice to get me through the coming year. If you want to juice your frost-compromised citrus, do it sooner rather than later as the damaged fruit will dry out over time.
Today, when I look at my citrus trees, my first reaction is to do something to help them recover. However, the wise gardener waits until the extent of the damage becomes apparent. Prune too soon and you may remove parts of the tree that could recover if left alone.
Pruning too early may also encourage new growth that is susceptible to cold weather. It is also best to delay watering and fertilizing until spring. Resist watering until new growth appears, and avoid fertilizing until you know the full extent of the damage and have pruned the dead parts. The pruned tree, being smaller, will not need as much fertilizer as before. For now, just kick back and wait until spring or even summer.
Wait to prune until trees show signs of new growth. Identify the branches damaged by frost. Branches that aren’t generating new leaves need to be removed. In some cases, the bark will have a different color than the rest of the tree, or even begin to fall away.
Make all pruning cuts into living wood. Clean pruning tools in a mixture of 10 percent bleach and 90 percent water to prevent spreading disease between trees. If you are pruning more than one citrus tree, clean the tools in between.
Wait to water until the soil has dried out and there is new leaf growth. With fewer leaves to evaporate the water, damaged trees are less thirsty.
When new growth appears in spring, begin fertilizing. Several light feedings are better than one heavy application. Choose a fertilizer formulated specifically for citrus trees. These products are high in the nitrogen and chelated iron that citrus trees need.Apply a two-inch-thick layer of mulch around each tree, extending the mulch beyond the drip line but keeping it at least six inches away from the trunk.
Spring begins on March 20, so I will have to ignore my freeze-damaged trees for a few months before I can pick up my pruning shears and get rid of the unsightly leaves, twigs and branches. Fortunately, now is the time to start seeds for late-spring planting so I won’t be without something to do.
Workshop: Join Napa County Master Gardeners for a workshop on “Rose Pruning” on Saturday, January 18, from 10 a.m. to noon, at the University of California Cooperative Extension (address below). January is the best time to prune your roses. Come learn pruning techniques from a certified Rosarian. Bring your rose questions. Online registration (credit card only)
Mail-in registration (cash or check only).
Napa County Master Gardeners welcome the public to visit their demonstration garden at Connolly Ranch on Thursdays, from 11:00 a.m. until 1 p.m., except the last Thursday of the month. Connolly Ranch is at 3141 Browns Valley Road at Thompson Avenue in Napa. Enter on Thompson Avenue.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.