By Jennifer Granneman.  Above ground, plants stop growing in winter. But below ground they tell a very different story. During the winter months days are shorter, providing less sunlight that plants depend on to grow. You may know that many animals hibernate or migrate to survive the cold, but have you ever wondered how plants survive in winter?

Even though winter in San Antonio can appear quiet, underground there’s a lot going on. Winter is one of the most important times of the year for plants to grow stronger and brace for our next hot and dry Texas summer.

This article explains how plants survive in winter and why planting in fall and winter can give your garden a WaterSaver head start.

Winter survival 101 – how plants cope with the cold

• Dormancy: Many plants sleep to save energy and water by entering dormancy, a period of rest similar to hibernation. When temperatures drop and days shorten, the above-ground growth of plants slows or stops as they take a well-deserved nap.

• Natural antifreeze: Plants pump water out of their cells down into their roots, leaving behind a sugary sap which often acts like antifreeze during the winter. Through this natural process plants can prevent ice from forming in their cells and protects them from freezing damage during occasionally cold nights.

• Food storage: Just like squirrels store nuts for winter, plants store extra carbohydrates (food) in their roots and crowns in fall. The stored food helps roots stay active in the winter. The roots continue to store reserves during the winter so when the plant reawakens in spring it will have enough food for leaves to bud.

• The secret life of roots: Even though the above ground growth stops, below ground it’s a different story. In our mild San Antonio winters, our soils usually don’t freeze, which allows roots to stay active and continue to grow. A recent study even found that some roots can continue to grow in frozen soil!

Roots and shoots follow different calendars with roots prioritized in winter, while stems and leaves take the lead in spring. Here’s what roots get up to (or rather down to) during the winter:

• Developing new fine roots
  • Repairing roots damaged in the summer heat
  • Growing down deep to reach moisture deeper in the soil
  • Storing new carbohydrates to get ready for spring growth

Why Texas native plants handle winter so well

Native Texan plants have learned to live with Texas weather and are acclimated to the occasional freezes, dry spells and soils. Because they’re so well adapted to our weather, native plants that are planted in fall or winter often grow stronger and establish more quickly than those planted in the spring. Healthy growth of winter roots can lead to:

• Higher plant survival in summer
  • Better soil health
  • More resilient, low-maintenance landscapes
  • Lower irrigation needs in summer
  • Winter is the season when root growth – and water savings – begin!

Survival spotlight on salvia

Native salvias, like mealy cup sage (Salvia farinacea), are great examples of plants built for winter survival in Central Texas.

• Food storage – Mealy cup sage stores up carbohydrates in its roots during late fall to help survive winter.

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• Dormancy conserves energy and water; top growth of salvia is frost-sensitive and dies back in winter.

• Rooting for roots – the root system of mealy blue sage remains active and continues to grow, even at low soil temperatures.

• Spring regrowth – the roots that accumulated carbohydrates during late fall serve as energy reserves for spring regrowth.

Practical tips for gardeners

Here are some simple tips to help your plants survive the winter. When you work with the natural winter cycle, plants have the chance to grow deeper roots, need less summer watering and survive our tough Texas summers.

• Plant in late fall and winter.
  • Choose native plants.
  • Add 1-2 inches of compost to the topsoil to increase water-holding capacity and improve soil texture.
  • Add 2-4 inches of organic mulch to protect roots from temperature swings and freezes, reduce evaporation and suppress winter weeds.
  • Don’t disturb the soil around established plants.
• Water strategically, like newly planted plants; established plants survive on rainfall alone.

Jennifer Granneman began her career in marine science, studying ecosystems at the downstream end of the water cycle. Over time, her work has migrated upstream, where freshwater decisions shape everything from healthy rivers to resilient landscapes. Her appreciation of water started when she took up scuba diving as a kid, and she still prefers being in or on the water whenever possible. As a conservation manager, she oversees the rebates and coupons programs to help residents save water while creating functional and beautiful landscapes. When she is not working (or underwater), she can usually be found gardening with minimal water alongside her son or exploring San Antonio’s beautiful parks.