Floras Suffer from Freezes

Austin continues to feel the impacts of freezes on our plants

By Claire Newmark

Anticipation of a snow day filled the halls of LASA High School. Students trudged along under a shadow of exhaustion when suddenly they saw a cloud of ice in the air. Thus the contagious bubble of excitement spread with rumors of a snow day. They walked home with a bounce in their step and fell asleep with a smile on their faces.

Unfortunately for the students, soft, fluffy snow did not fall that night. Instead, they were cursed with freezing rain. The rain coated trees in a layer of ice, weighing down the branches. As the night went on, the ice got thicker and thicker, until the branch splintered and snapped with a resounding crack, falling to the ground. The rain continued into the next day and the one after, bringing with it many more branches to the ground.

Disastrous freezes in both 2021 and 2023 caused large scale power outages. Additionally, these freezes have left devastating effects on Austin’s flora and we continue to see their lasting impacts today.

Colleen Dieter is an ISA (International Society of Arboriculture) Certified Arborist. She offers help and advice for gardening and landscaping.

“One of the biggest losses that we had at my house [in 2021] was a big American Elm tree that shaded the southwest corner of the house,” Dieter said. “The ice during that storm broke the tree in half because it had a defect and basically half of the top of the tree fell off.”

Additional losses that she had were two huge fig trees. Although they were not killed, both trees experienced large amounts of damage and they are still trying to recover.

“The younger wood split open because the water inside of the branches expanded when it froze,” Dieter said, “So it busted open all the branches really high up and that killed the ends of the branches.”

Matthew Gaston is the Education Director at Zilker Botanical Garden. He studied genetics, plant biology, and education at the University of California, Berkeley.

In 2021, the freeze saw many plants damaged or dead. Many of the gardens in Zilker Botanical Garden

Scenes from around Austin during and after the 2021 and 2023 freezes were entirely changed by the freeze. One of these was the cactus garden.

“The cactus garden was magnificent,” Gaston said. “It had Saguaro cactus and Barrel cactus, and it was full of cacti and really well designed, really well planted. That huge freeze killed about half of those cacti and then damaged the other ones.”

“The cactus garden probably only has about 40% of what it once had, and a month ago they just removed all the soil and put in new soil,” Gason continued. “Hopefully within the next month or two we can replant it so that it can grow into what it once was. It’s taken two years to get the cactus garden even to where it was in 2021.”

In 2023, Zilker Botanical Garden “had a lot less damage than most places around Austin,” Gaston said. One reason this is the case is “that [they] have good tree care to begin with, so any of the potentially problematic snags or branches were already removed.”

Despite having less damage, the fallen branches after the ice storm were a pain to clean up.

“It took four days for maybe 15 people to clean up the 28 acres,” Gaston said. “It was a ton of work.”

Janice Brown is the head gardener at Mayfield Park. She has been taking care of the Park for 15 years.

Similarly to plants at Zilker Garden, Mayfield Park’s flora also suffered damages in the 2021 and 2023 freezes. However, the park works to include a garden of primarily native flora that thrive in Austin.

“A lot of things, we cut back obviously because they were dead on the top, but their roots were all fine,” Brown said.

Additionally, spring in Mayfield park was a little less lively than years prior.

“The [plants] that had already started making their flowers,” Brown continued, “got frozen and they didn’t come back that year.”

In general, “Plants that are native here will do much better,” Dieter said, than plants that are not native here. However, native or not, young plants need a little extra attention during a freeze.

“Plants that are newly planted can be really vulnerable because they don’t have all of their defenses ready,” Dieter said. “They don’t have all of their starches and sugars stored in their roots that established plants would, so when they get damaged, they often don’t have enough resources stored up in their roots to be able to grow back or heal.”

Plants that are adapted to cold temperature as well as native Austin flora are better suited to survive freezes.

“We’re USDA, zone eight B, which basically means the mean annual minimum temperature in Fahrenheit is 20 degrees Fahrenheit,” Gaston said. “That means all the plants that are rated for eight B or lower will survive.”

There are also ways to help plants survive a freeze even if they are not adapted for it, or are too young to be able to bounce back.

“Putting frost cloth would be ideal and then watering the plants prior to a good freeze is a general practice with the exception of cacti,” Gaston stated. “You don’t want to water cacti because you don’t want them to expand, and then when it freezes, that ice expands and then they burst.”

Watering plants, other than cacti, is a very important part of preparing them for a freeze because “It helps the roots and the ground stay warmer and they’re tougher if they’ve been watered,” Brown said.

The loss of plants, even with proper care, can be emotionally draining.

“I felt sad, fearful, discouraged, and traumatized,” Dieter said. “I felt worried, and it wasn’t just my garden either. There’s all my customers too and a lot of landscapes that I’m really attached to, a lot of plants that I love a lot. Tree damage was very distressing because the trees are so valuable in terms of monetary value and the services that they provide, like cooling your home. Also, just in their size and the investment of time that you put in waiting for a tree to grow and planning the whole rest of the landscape around the tree. So, when the trees are damaged or lost, it’s devastating and can be devastating to the landscape and to the earth.”

Dieter continued by saying “There’s a part of me that is an observer and experimenter, so once I accepted the situation, I felt intrigued to see how things would grow back and what shape they would take.”

As a gardener, Brown agreed with Dieter at the wonder of plants, their resilience, and how they handle the freezes.

“I wasn’t terribly worried,” Brown said, “to me, it’s more interesting to see what happens.”

These freezes have not only changed household gardens, but they have left scars on the plants and reshaped the landscape of the city.

“I still see that there’s been a freeze, all over town,”

Dieter said. “I’ll see the tree damage. I can tell when I come to a customer’s house and there’s a stump. I’ll say, ‘Oh, did you lose a tree in the freeze?’ Or I can tell the branches are broken in a funny way. But it’s more like a memory of what Austin used to look like because there used to be Agave Americanos everywhere. And there used to be prickly pear cacti everywhere. And they’re gone. And there used to be more palm trees everywhere. And they’re gone.”

This devastation from the 2021 and 2023 freezes is significant, not only because of the scale, but also because of the timing.

“In all the time I’ve lived in Texas there’s never been three bad winters in a row,” Dieter said, “and we’ve had three bad winters in a row now.”

Gaston shares the sentiment.

“I grew up in San Antonio,” Gaston said. “We had like one significant freeze growing up and now there’s like one every year.”

While on the surface, broken branches and dead plants can be seen, the issue of the freezes goes a lot deeper. If extreme temperatures in Austin continue, larger scale issues will persist.

“It’s really stressful to me that there’s so much tree damage because the trees are the best defense that we have against climate change,” Dieter said, “because they’re huge and they’re able to draw so much carbon out of the atmosphere and store it in their bodies as wood and put it back into the soil through their relationships with soil microbes. Seeing them get destroyed and torn apart by climate change when we need their help with climate change is really upsetting.”

Gaston also comments on the large-scale issues of climate change.

“[The freezes are] related to changes in the atmospheric gasses,” Gaston said, “and the emissions in the way that capitalism pushes for product and money over the wellbeing of everything.”

In other words, our society prioritizes cheaper things even if it hurts the environment more than something comparatively expensive. Gaston brings to our attention that although our decisions may not appear to be contributing to climate change, something as simple as choosing between packaging at the grocery store can greatly impact the environment.

“Then it goes down to even smaller scale levels,” Gaston continued, “Energy companies need to find ways to supply energy and so people don’t lose power when it freezes because it’s going to be freezing all the time. And so then you can’t have trees over the power lines since we’re probably gonna lose a lot of the canopy of trees as time goes on.”

If climate change continues as it is right now, these freezes will impact Austin life and people will have to adapt lest plants will continue to die at unprecedented rates.