After the Freeze, What should a Gardener Do?

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. 

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.

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
branches.

• 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!"

 

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.

Hard Freeze Yard and Garden Tips

     A few weeks ago, we talked about strategies to protect your plants from any expected mild frosts, when morning temperatures dip just below 32 degrees for an hour or two. 

     But what if the often predicted December freeze, when temperatures fall into the 20's for several hours each morning, settles into the area?
    
     Many of us learned this drill back in 1990, when consecutive low morning temperatures of 22, 18, 21 and 23 in Sacramento descended upon us during the period of December 21-24. Temperatures did not get above 25 degrees in parts of the San Joaquin Valley for three to five days and all time record low temperatures were set at Sacramento, Stockton, and Bakersfield. Many records were set for duration of freezing temperatures. The agricultural industry was devastated as acres of trees, not just fruit, were destroyed. Thirty-three counties were disaster-declared.

     Homeowners learned which plants don't like it cold (hibiscus, geraniums and other plants popular in the Bay Area and Southern California); and, which plants were the hardy survivors (another reason the oleander was chosen for the Highway 99 median strip). 

     Here's a last minute checklist for your home and garden if the TV weather people tell you tomorrow's low will be in the mid-20's:
• If it hasn't rained, water plants thoroughly, especially container plants.
• If possible, move sensitive container plants next to a south or west facing wall.
• Cover citrus and other sensitive plants with burlap, row cover fabric or sheets (be sure to keep the sheets dry). Tent plastic sheets over the plants; don't let plastic touch plant leaves. A light bulb placed in such a plant can offer a few degrees of protection.
• If using an anti-transpirant polymer coating material such as Wilt-Pruf or Cloud Cover, apply at the warmest time of the day, or at least six hours before an expected frost. However, a study at Oregon State University concluded that these products may actually be detrimental to certain plants during a freeze. If using these products, thoroughly water the plant before applying.
• Disconnect hoses and drip lines, removing end caps. Lay out straight.
• To prevent broken grass blades, don't walk on a frozen lawn.
• Remove the lowest sprinkler head to drain.
• Cover unprotected faucets and pipes, including any spa or pool equipment.
• To prevent frozen attic pipes, let lukewarm water trickle out of the indoor faucet farthest from the inlet. Also, let faucets with pipes running along an outer, north facing wall trickle during the night. 
• Open cabinet doors to get more heat to the pipes. Close the garage door if water pipes pass through the garage.
• Setting your thermostat nightly at 55 can add needed heat to the attic pipes.
• If leaving the house for a vacation during an expected freeze, turn off the water to the house, and open up the faucet farthest from the inlet. Be sure to turn off your water heater.
• To prevent cracking tile, run your pool and spa equipment during the freezing hours.
• Don't forget about your pets during a prolonged freeze. Bring them indoors at night. Move or replace their drinking water. Break up any frozen water in bird baths.
    
    

Their is some good news connected with a possible freeze: populations of yellowjackets, eucalyptus-feeding red gum lerp psyllids and grasshoppers could be greatly reduced in 2010.