Houston Botanic Garden is open daily, 9 a.m. to 5 p.m., with COVID-19 safety protocols in place. Facemasks are required to visit. View Garden Rules.

Houston Botanic Garden is open daily, 9 a.m. to 5 p.m., with COVID-19 safety protocols in place. Facemasks are required to visit. View Garden Rules.

Where do Houston gardens grow from here?

Thoughts on post-freeze recovery

Feb. 23, 2021
 
In a mild climate like Houston’s, we’ve been tempted to do some zone-pushing, growing things that are slightly – and sometimes even more than slightly – out of our hardiness zones. Stuff like that makes gardening even more fun, right? At least until Mother Nature throws a curve ball in the form of practically once-in-a-lifetime low temperatures, with a heaping helping of winter precipitation to boot.
 

Don’t despair!

What is a Houston-area gardener to do now? While some losses are inevitable, I think we’ll be surprised with what survives in the longer run. Plants are very resilient, and many that look dead now could show signs of new growth in as few as a couple of weeks if the weather stays mild from now on.

You’ve probably seen competing ideas in the last few days on the topic of whether or not to remove “the mush.” You know, the “ugly,” wilted brown debris littering garden beds all around the region, where lush green foliage was just a few weeks back.

Do this now

Now that we are several days out from the worst winter could dish out, we advise going ahead and removing all mushy growth from any of your herbaceous plants, as well as things like cacti and succulents. This layer of unappealing mush provided a little protection during subsequent freezes, but with the current warmup and no chance of freezing temperatures in the immediate forecast, getting that stuff cleaned off will allow air circulation and sunshine to return to your plants. Air circulation is your plant’s best friend right now! It plays a very important role in preventing future fungal problems and rot. 

If you are new to gardening, you may be wondering, “What are examples of herbaceous plants?” 

  • Agapanthus
  • Aloe
  • Amaryllis
  • Canna
  • Hemerocallis (daylily)
  • Iris
  • Farfugium/Ligularia
  • Ferns
  • Lantana
  • Musa (banana)
  • Strelitzia (bird of paradise)

 

Even cool-season plants such as Viola (pansy), snapdragons, ornamental kale and cabbage, Swiss chards, lettuce, etc. may have succumbed to this extreme cold. They are cold tolerant, but not necessarily of the type of cold we saw for as long as we did. Some may come back, but you’ll need to get them cleaned up to give them a chance.

When it comes to semi-hardy plants that have likely died to the ground, we expect them to return from the base or the roots. For most of these, it should be fine to go ahead and cut them back hard, as they sometimes die back almost to the ground during a normal winter here anyway.

  • Asclepias (milkweed)
  • Carissa (Natal plum)
  • Duranta
  • Tecoma (Esperanza)
  • Galphimia (golden thryallis)
  • Hamelia (hummingbird or firebush)
  • Hibiscus
  • Ixora
  • Jatropha
  • Oleander
  • Plumbago
  • Salvia (the perennial types) 

 

As for things like Cycas revoluta (Sago palm), if the leaves are completely brown, you can remove them all the way to the trunk, and for roses, it’s time to prune them anyhow, so if you had not done yours, go ahead and do so now.

Wait at least two weeks

For other, more-woody plants, such as most trees and shrubs, it would be better to wait a couple more weeks, at a minimum, to begin cutting them back. It may take at least that long for the true extent of their damage to show itself, and cutting back too far or too soon can do more harm than good. Many have dormant buds along their stems that will eventually begin to initiate growth as the weather warms. Cutting back too far can remove these buds needed for future regrowth. Once this new growth starts, you’ll know exactly where to cut!

  • Citrus
  • Azaleas
  • Callicarpa (beautyberry)
  • Camellia
  • Cleyera
  • Fig
  • Gardenia
  • Loropetalum (Chinese fringe-flower)
  • Raphiolepis (Indian hawthorn)
  • Viburnum (most species)

 

Patience is key

Let your plants have the time they need to heal. You may actually be rewarded with less work in the end and, believe it or not, the possibility to welcome back to your garden even more beautiful plants down the line. In the meantime, if you want to see examples of how to clean-up and/or care for your plants, come visit us at the Houston Botanic Garden, where you’ll find our team of horticulturists working hard to bring about in our acres and acres of beds the same kind of recovery you are seeking at your home. No matter the season or reason, we love talking plants!

Brent Moon
Horticulture Manager