We are fortunate in the Houston area to be able to garden pretty much year-round. Sure, there are times when we get some knee-knocker cold spells that do a number on many of our tropical plants. But, if you do a good job of getting those tropicals ready for the season, they should come roaring back in the spring.
A couple examples are hibiscus and bougainvillea. You can lump a whole bunch of other tropicals into this category (like philodendron and crotons), and you can adjust the care tips for any you might have in your landscape.
Here are the rules of thumb:
- Trim the plants down to a manageable level prior to the first hard cold snap. They'll be easier to cover with sheets, blankets or frost covers.
- You only need to cover when the temperature is REALLY at freezing (32 F) or below.
- Cover them only with sheets, blankets or frost covers (also known as freeze covers or frost blankets). Do not cover with plastic or tarps alone. You can use tarps or plastic on top of the sheets, blankets, etc.
- Keep them heavily mulched to insulate the root system and preserve moisture.
- Water the root systems thoroughly before a serious cold snap.
- Remove the blankets the following day if the temperature rises above freezing.
- If a part or limb didn't get covered and looks a little damaged, trim it off before it rots.
If you do happen to lose a plant due to freezing, you probably won't know about it until at least February. Often, you can lose many limbs, but the core of the plant and the root system are very much alive. Just keep pruning the dead wood as late as March.
And if you wonder if it's worth the effort trying to keep tropicals alive, remember they are relatively inexpensive to replace. Some people buy containerized tropicals in late summer or early fall (when they're often half-price), and baby them in a controlled environment through the winter. Then they have replacements for landscape plants that get ravaged by the winter, and they don't have to get out there and cover/uncover religiously when cold spells come.