I wouldn’t call what we experienced the last few mornings a “hard freeze,” but we did have some freezing weather, some sleet and, in portions of our listening area, some snow. So, there will be a number of freeze-damaged plants to deal with.
But one thing is not up for discussion when it comes to cleaning up freeze damage: We will not touch fruit trees … especially citrus … until at least February. Otherwise …
1. If it's crispy and brown, cut it back to green wood. Hibiscus, lantana, hamelia and other perennials are great examples. Or just leave crispy and brown freeze-damaged plants alone until you feel certain no more freezing weather is ahead. If you do cut back damaged plants to green wood, be sure to super-protect them if another freeze is forecast. There are two reasons:
- A. The fresh cut will act like a straw, pulling freezing temperatures directly into the plant. That can totally kill a perennial that otherwise could handle such weather.
- B. If you cut back, and temperate weather prompts new growth, the new parts will be highly susceptible to damage from any future freeze.
2. If you cut a brown-and-crispy plant to the ground and see no sign of green, but the root system seems to be firmly locked in, consider leaving it alone to see if it comes back. Be sure to protect what’s left during any future freeze. If, however, the root system moves around easily — like a car's stick shift — it's dead. You can remove the whole thing.
3. If it's mushy, gushy or gooey, get rid of it! Cut it out, remove it - do whatever it takes to get the nasty stuff out of there. If you cut all the spongy parts away from tropicals like bananas or split-leaf philodendrons, you’ll likely be left with just a tiny bit of green material near the ground. Protect that from future freezes that can kill root system. But you really need to get the squishy stuff out, because it could harbor fungal diseases that will be pulled into the remaining plant.
4. If a palm frond (those of queen palms are good examples) is drooping over, cut it out or back. If a palm frond is standing up, leave it alone. After the January 2010 freeze, we had to wait months before we knew if some palms were coming back. The only true way to determine if a palm is dead is to examine the inside of the crown, where new growth emerges. But most of us don’t have equipment or ladders tall enough to do such visual observations. A racquetball buddy who was worried about his queen palms sent me a picture saying he thought they looked fine to him. I told him that I didn’t want to rain on his parade, but he might not know the full extent of some palm damage for another 30-45 days.
5. On palms small enough to get to the fronds (a dwarf pygmy date palm is an example), pull on those in the interior to see if they stay attached. If they easily slide out, the plant is dead. If they hold tight, the plant may still be alive, but you will have to wait and see. And if you removed some fronds, but you think the palm may still be alive, remember to protect the open slots during any future freeze. Otherwise, dangerous cold will be drawn into the plant through those open areas.
6. If you feel confident that we’ll get no more hard freezes through mid-February, it's time to “scalp” the yard. Essentially, you'll try to vacuum up any dead grass so live roots are open to air, sunshine, water and fertilizer. Do it by mowing with the mower deck lowered a notch or two. Years ago, a scalping would mean lowering the mower by 2-4 notches. These days, though, we know it’s better to give the lawn more of a "haircut." But, again, you have believe there are no more freezes coming. Otherwise, just rake out as much debris as possible and skip the mowing. As you might suspect, another hard freeze could actually kill a scalped St. Augustine lawn. So, don’t do it until at least Feb. 15, unless you are really confident we’re done with freezes.
7. If you think your St. Augustine lawn has a lot of thatch built up, don't mechanically de-thatch - give it a haircut instead. There are products - essentially anything containing humus or humates - that will help break down the thatch. We’ve also learned in the past two years that trace minerals and trace elements can help to break down the thatch, if you can’t find humates.
Please share this information with friends and neighbors, and encourage them to tune in GardenLine each weekend to learn more about recovering from extreme weather and succeeding with all types of gardening along the Gulf Coast. And get hooked up with GardenLine on Facebook, too. We post timely information there on a regular basis.
PHOTOS: The Ohio State University, LSU Ag Center