Kids sledding down the hill at Miller Outdoor Theater. Snow blanketing the sandy beaches of Galveston. Social media bursting at the seams with photos of wintery white Houston. These are normally not common occurrences in the Bayou City. Yet, within the past four years, Houston has had two named winter storms that have dropped measurable amounts of snow. In February 2021, it was Winter Storm Uri. This week’s troublemaker was Enzo.
Many of us who have gardened in Houston for years are flummoxed. We have been used to gardening year-round with occasional light freezes or a rare hard freeze. While Houston might have snow every four or five years, lately the unprecedented winter weather events have been so dramatic they have shut down the city for a day or two. And the winter storms have wreaked havoc on our plants and gardens, not to mention pipes and roads.
Fortunately, our meteorologists were on the ball this storm and we were warned well in advance of the impending wintry precipitation. Most homeowners took precautions to protect people, pets, pipes and plants. However, no matter how well outdoor plants are covered, a hard freeze of 28 degrees can still do damage. The good thing about the snowfall across the city is the fact that snow can sometimes work as insulation, helping to keep roots protected from the drop in temperatures.
The semi-tropical weather in Houston means that many of us love to grow tender plants that cannot withstand temperatures below 32 degrees and sometimes, they don’t do well under 40 degrees. Most homeowners know to bring those indoors. However, we also have many large specimens planted in the ground that just have to be left to face the cold. While covering plants with frost fabric or sheets can help, it usually only adds a couple of degrees from the trapped heat of the soil. For some plants, that may be enough. Others may lose a lot of leaves, but still be alive at the roots.
I have come to expect that my huge Angel Trumpet will freeze back nearly every year. It was hard to accept in the beginning but it comes back from the roots every spring and this year, it grew bigger than ever before. Of course, as it tends to go with gardening, it had just started blooming when Enzo came along. It looks pathetic now but I will have to leave it in its sorry state until it is safe to cut back the stems.
Here are a few tips about helping your plants recover after the fun of the snow wears off.
Assessing damage:
The weather forecast is looking brighter this week with warmer temperatures but also rain. Once the temps are above 32 degrees, it is time to get the covers off so that the plants will get sun. Also, if it rains and the plants are still covered, they will get smooshed under the weight of wet blankets and fabric. The rain will help, but if your plants have been covered for days, they will probably need to be watered beforehand.
Though many plants will have suffered damage to the leaves, oftentimes the stems and roots are fine. It may take a few days, or even weeks, to visually see the damage done by the freeze. It is still too early to do major pruning of brown or dead plant material, no matter how unattractive the plants or shrubs appear. Houston could still see another freeze before spring. After all, winter storm Uri happened in mid-February, a time of year many Houston gardeners are usually planning their spring gardens. Plants that are cut back are more susceptible to another frost. The ‘wait and see’ approach is the best option unless there is a dangerous situation like a broken tree limb.
Many plants will look dead simply because of their damaged leaves. However, unless the stems are split, the plants, especially shrubs like azaleas, will drop the dead leaves and put out new ones when the weather warms. Some other ornamentals such as hydrangeas are meant to lose their leaves anyway. Roses are hardy down to 20 degrees, so they should be left alone until the yearly mid-February pruning.
The death count will be skewed toward annuals such as penta, angelonia, salvia, Mexican heather, petunias and other plants that prefer warmer weather. However, many of them will come back from the roots despite being annuals. In mid-February, if there are still dead stems and leaves, they can be cut back to a few inches from the ground. New green growth may emerge. Gardeners should give it some time. I almost dug up several Mexican heather plants a couple of months after a freeze only to discover new growth. It won’t happen with every annual plant but when it does, it’s exciting. And money-saving.
Some cold-weather annuals may have very little damage. Right now, many of my dianthus, lobelia and stock look fine. Some shrubby plants such as lantana and plumbago will need to be cut back in late February. They make look awful now but they will almost always be revived. Gardeners should give plants time to heal before declaring them goners.
Some tender-leaf and tropical plants will need to be cleaned out if the stems and leaves are mushy because fungal problems could occur. However, if the plants are cut back, they will need to be well-protected if freezing weather is forecast.
Many homeowners will not want to live the next month with dead-looking foliage and may choose to cut it all back. That’s a roll of the dice considering the possibility of another freeze. However, a thick layer of mulch and a ready supply of frost fabric might be able to avert a major loss of landscaping.
I didn’t plant a fall vegetable garden this year except for a few leeks and onions. I mounded the soil around each of them before the storm and the snowfall actually helped to insulate them. I think they will make it to harvest. I bought one tomato plant this fall and potted it, bringing it inside each time the weather dropped below 45 degrees. It has rewarded me with with five winter tomatoes for an investment of $10. My three pepper plants leftover from summer were all fruiting when the winter storm was predicted so I picked what I could. Now, they’re done for. The strawberry plants that I covered with an empty soil bag, however, seem to have made it unscathed.
I no longer have in-ground citrus trees but for those who do, this storm may not have been cold enough to kill them. Because they grow all year long, the leaves are more susceptible to cell damage during a freeze. It can take quite a long time before the leaves show it. That doesn’t mean the wood is also damaged. Any pruning should be held off until late spring. Split stems and gray color are evidence of possible death.
When all threats of a freeze are gone, we can then cut back damage, clean out the beds and fertilize plants to help get them back on their feet.
The Silver Lining:
As we learned with Winter Storm Uri, many plants are resilient. Some actually thrive when they get an opportunity to go dormant. My roses, and those of other gardeners I know, bloomed beautifully the following spring. This past December was quite warm and I worried my two peach trees would not get enough chill hours. I am hoping that this recent cold spell will help.
Freeze damage can also help those of us who aren’t very good at pruning. When we cut back the damage, we end up with tidier flower beds. And more room to plant new babies.
If we allow our gardens to rest and heal on their own, we may discover that less human intervention is actually beneficial. This rest period is good for gardeners as well. It’s a time to reevaluate what we want from our landscapes, read a few garden design books and scour the internet for advice on growing vegetables.
After all, we Houstonians could be planting tomato seedlings next month.
