Q: Can you give me some information on pansies and how they stay alive during the freezing weather? Do they have plant anti-freeze in them? Does the water go down to the roots at night?
A: Pansies are members of the Viola family. They are kissing cousins to the wild violets that lawn lovers find so difficult to conquer. Violas and violets have been cultivated for hundreds of years, both for their flowers and for the perfume they produce. Our hybrid garden pansies, Viola x wittrockiana, are annual flowers but all other violas are perennial.
Pansies protect themselves by allowing moisture to escape their leaves as temperatures fall. Other plants cannot do this, so when the temperature goes below freezing the water in their cells freezes and ruptures the cell walls. That’s what happens when you leave a houseplant on the patio during a freeze. Dry cells, though, can’t rupture. They just go limp. It is normal to see pansy leaves completely wilted at dawn but green and perky by noon. That’s why it is important to keep the soil in pansy beds moist after a freeze…. so their roots can re-hydrate the leaves.
Other plants also protect themselves in this manner. My neighbor’s southern magnolia looks pretty droopy after a hard freeze but after a few hours of sunshine the leaves regain their green glossiness. Old time gardeners even say that the taste of turnip greens improves after a frost, due to its efforts to protect itself from the cold.