Nature's Own Antifreeze

Hellebore in my garden

Have you ever wondered how certain plants are able to withstand sub-freezing temperatures and bloom even with the ground blanketed by snow and ice?

The secret to their longevity lies in compounds known as antifreeze proteins (AFP), which work to protect the plant's cells from the degenerative effects of freezing temperatures. It may sound like science fiction, but some plants have cells that don't freeze. Here we'll take a closer look at nature's own antifreeze, and reveal some of the plants known to possess them.

Plants aren't the only living organism to contain antifreeze proteins. Certain animals, fungi and even bacteria also carry these proteins. Scientists believe antifreeze proteins are an evolutionary trait used to help living organisms survive.

Plants carrying antifreeze proteins will typically still develop ice on the outside (extracellular freezing), but the inside will remain unfrozen. From the naked eye, it may appear as if the plant is frozen with ice coating the leaves and stems; however, the cells' interior structure will remain solid and unaffected by the ice and freezing temperatures.

Hellebores

Hellebore Emerging in my Winter Garden

Hellebores are a group of about 20 herbaceous or evergreen species from the Eurasian genus helleborus.  They are one of the earliest blooming perennials and it's not uncommon to find Lenten rose (helleborus orientalis) emerging through the frost-covered ground. They are able to endure such cold temperatures because of the antifreeze proteins present in their cellular structure. These proteins prevent the inside of the plant from suffering frost and cold damage.

If you plan on growing hellebores in your garden, you'll want to use caution and avoid touching them with your bare hands because of their toxicity to humans. Prolonged exposure to the skin can result in rash and/or irritation.

Snowdrops (Galanthus)

Snowdrops at NY Botanical Garden

Another type of plant that's known to possess antifreeze proteins is the Snowdrop (galanthus). This evergreen perennial gets its name from the milky-white leaves resembling snowdrops that form from a single stem. With an average height of just 4-6 inches, snowdrops are small, but they make wonderful additions to any outdoor garden. One of the reasons why so many people choose to add them to their gardens is because of their ability to bloom early.  Snowdrops remind us that Spring is coming!