Sunday, November 28, 2010

Post-Freeze Garden Tips

The average frost season for Sacramento is about two months, primarily December and January. But temperatures below 32 have been recorded as early as the first week in November; as late as the third week in March. This year, it was a Thanksgiving freeze, when temperatures plummeted into the low 20's Thursday morning, remaining there for more than 8 hours. Friday morning's lows also dipped into the 20's. And that's a recipe for definite plant damage.
 After several days of bone-chilling mornings with temperatures dipping into the low-to-mid twenties, should shivering gardeners:

a) remove all plants that look frost-bitten; 
b) prune away all freeze-damaged plant parts;

c) Purchase and plant again this weekend those same varieties of trees, shrubs, perennials and annuals;

d) water the garden, even if the plants resemble toast;
e) fight the urge to prune and plant by staying indoors, next to the wood stove?

The answers happen to be the easiest to accomplish on a cold weekend: d) and e).

Even if plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors. 

Hostas will get new growth from the base.
Parsley can take a freeze. Tomatoes? No.

So, keep the shears in the garage and let the dead portions of the plants protect the understory. It may take until mid-Spring before you see new growth; patience is key before you pick up the pruners.

Make sure your garden and potted plants remain moist. Water
gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.


Other frosty garden tips that bear repeating:
• If you still have cold-susceptible potted plants on the porch or patio, move them to a sunny spot indoors or to a west or south-facing outdoor wall.

• Another way to achieve a few degrees of protection: construct a tent around a freeze-threatened plant, especially citrus, using frost blankets or row cover material. Your local nursery will have several products that will do this job. Old bed sheets work well, too.

• The larger sized Christmas lights or a couple of 150-watt light bulbs located in the central area of an orange tree (or any other cold-intolerant shrub) may add two to four degrees Fahrenheit of protection.

• Harvest any citrus fruit that is ripe, especially on the outer

• Wrap any exposed plastic water pipes; cover outdoor faucets, as well.

• Adjust your pool, spa or pond filtration timers so that they are running when the chance of freezing temperatures is greatest, between 2 and 9 a.m. Moving water is less susceptible to freezing.

• Make sure the backyard birdbath isn't frozen over in the morning.

• Daily fresh water for dogs and cats is also a good morning habit.

And what about those plants that have frozen past the point of
return? Should you replace them with the same varieties? That frozen ficus may be Mother Nature's way of telling you: "Hey! This ain't San Diego! Pick outdoor plants that can take colder temperatures!"


Coleus, a summer annual here: It's dead, Jim.

From the garden e-mail bag, Rob asks: "A lot of my lantana was burned by the cold weather. Should I trim in winter or wait until spring?"
Lantana is from the tropics, so it is a borderline plant here.
A light frost usually just damages the outer leaves; but a heavy frost or freeze may kill the entire plant. The good news: it may come back to life with new growth from the base, but not until late in spring. In the meantime, do nothing. Those dead branches may be keeping the base alive.

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