Question: What if there's an unusually cold spell in winter?

Answer: Know your area's USDA Hardiness Zone. That will tell you the average low temperature you can expect to see most winters. Hopefully your plants will have been chosen accordingly. If you have an unusually tender plant, or if temperatures are expected to drop lower than you would normally expect to be your coldest weather, follow these guidelines:

• Use compost, shredded tree leaves or some other form of mulch to moderate the rate of soil temperature changes.
• Water all plants carefully and deeply prior to the cold front.
• Cover the vulnerable plants with lightweight nursery fabric or old sheets. Secure the covers tightly in place, since most cold fronts are accompanied by strong winds. Provide stakes to support the cover if rain, ice or snow are expected.
• If you see what you think might be freeze damage, wait several weeks or even until spring to assess its magnitude. Even if leaves are scorched by cold, plants often send out new spring leaves to replace them. You'll know within a week or two if new growth of hollies, pittosporum, gardenias, oleanders and others has been damaged. Look for shriveling twig tissues. Bark near the soil line may also rupture.

REMEMBER: You lose about 20 degrees of winter hardiness in most woody plants when you grow them in containers, above the ground. Their root systems are much more exposed and vulnerable. Either wheel them into the garage for a day or two during extreme cold, or wrap them securely in sheets of insulation.