North Texas is in for a prolonged cold spell that could damage or kill plants, especially if they are newly planted or outside their native habitat. We are looking at a forecast of over a week of nighttime freezing temperatures, and not just freezing, but record-breaking lows for an extended period of time! With a predicted low of 5 degrees in Dallas at one point, you can expect it to be even colder in surrounding suburbs such as Plano.
What’s at Risk
Cold, windy weather can be a death sentence, especially for newly-planted plants. Plants that were planted within the past year may not have enough of a root system to support their spring growth after the cold spell ends.
Additionally, sudden temperature changes like we often see in North Texas – warmer weather followed by several below average, cold nights – don’t allow plants time to acclimate slowly, making frost damage and death more likely. And we’re seeing extreme cold following unseasonably warm weather. Sadly, this is a recipe for a lot of loss and damage throughout our landscapes.
Native plants have adapted to local weather conditions for thousands of years. They are acclimated to North Texas weather fluctuations, so generally, you don’t need to worry about any of your natives. But, extreme weather like we are now experiencing will put extra stress on even our hardy natives.
Preparing Your Garden for a Freeze
There are a few steps you can take to protect some of your plants, but with record-breaking conditions expected, keep in mind that protective measures will only go so far.
Several factors besides root establishment can affect plant survival. These include soil moisture levels. Plants suffer less damage if the ground is moist as moist soil can stay warmer than dry. Give the ground around your plants a thorough watering (use a moisture meter to determine if the soil is dry).
Additionally, consider microclimates when determining where to spend your efforts – is the area protected from north winds or close to the house which provides some radiant heat?
You can cover tender plants with frost cloth or old sheets, but be mindful that frost cloth can moderate temperatures only about 6-8 degrees Fahrenheit. Do not use plastic; it can burn plants if left on in full sun.
Bring your potted plants indoors or wrap them with blankets or frost cloth. Also, inexpensive clay pots will shatter so bring them into the garage.
Succulents and plants from Mediterranean areas (herbs like rosemary, thyme, and sage) are going to be especially susceptible. You can dig up some of your prized sedums, e.g. ghost plant, and save in your garage for spring re-planting.
Cool-season veggies can generally survive our winters, but with temperatures dropping so low for a prolonged period, they may not make it. Harvest what you can now before it gets too cold.
Don’t forget to disconnect and wrap your faucets, and drain your hoses and rain barrels.
What to Expect from Perennials
Some perennials may have already died back to the ground with the first hard freeze last year, but the recent warm temperatures mean some may be actively growing right now. I have an iris that bloomed 2 months ahead of schedule because it was fooled into thinking it was spring! New growth is not hardened off for the cold. This can make the plant more prone to damage, especially the tender new foliage.
For the best chance of survival, protect roots by making sure the ground is moist and mulched. There’s a chance that freeze-damaged perennials may take longer to reappear, so don’t give up on any dead-looking perennials right away – give them a season to bounce back.
Keep in mind that you may see brown spots on leaves and flowers where the cold has burnt the plant tissues. Your plant should be fine, but you may remove unsightly brown foliage if it bothers you.
For all other plants in question, check hardiness ratings to find out the lowest temperatures they can withstand, and protect accordingly. This information is available on plant labels, so be sure to keep a detailed record of what you plant. With a little googling, you can also find the hardiness zone for any plants you are unsure about.
For more on protecting your plants throughout the winter, see this post on winter garden tasks. Keep warm, and good luck! Are you making any special efforts to save anything in your garden?