The Tropics Are Just a Live Oak Away

The tropics are just a live oak away? Okay, maybe not. There are no coconut palm lined beaches magically appearing on the other side of my live oak tree. There is no secret door in the trunk that magically opens to a warmer, sunnier place. But.....there are tropical plants that thrive under the live oak.

Charleston straddles USDA Plant Hardiness Zone Ho-Hum (or 8b), with minimum temperatures of 15-20 degrees, and USDA Plant Hardiness Zone Ooh-La-La (or 9a), with minimum temperatures of 20-25 degrees. What grows in Zone Ooh-La-La? Think tropical hibiscus, some bromeliads, an expanded range of palms, tropical ferns. I want that! So I keep shoving more marginal plants under the protective canopy of my live oak.

The happy little collection of strobilanthes, aechmea, vriesea gigantea "Nova", and monstera in this November 30 photo was unscathed by the scattering of freezing temps that had knocked back other tender plants in exposed areas of my yard. Will they all make it through the winter? Who knows. I have serious doubt about the monstera and even the sturdier plants in that group may die if we have an exceptionally cold weather. In the meantime though, I love having that bit of color hanging on in my yard.

A live oak can help gain those few precious degrees that mean a tropical that would normally die is instead root-hardy (hopefully the case with the monstera) or that a tropical that normally would only be root-hardy is evergreen (for example, the Persian Shield). On a cold night, the closed canopy of the live oak acts like a cozy down blanket by trapping the warmer air radiated up from the ground. That same "blanket" also prevents plant cell damaging frost from settling on leaves and stems.

How much of a difference does it make? Seeing is believing. In a downtown Charleston park, this Persian Shield, lying just a few feet outside the dripline of a Live Oak, was top-killed by freezing temps a few days ago:

But just ten feet away, under the protective cover of the same Live Oak, this Persian Shield is untouched by the cold:

And because it hasn't been killed back in years, it has these great big leaves:

Same story with this groundcover which is also outside the dripline of the Live Oak:

And again just ten feet away, is the same plant, same day:

I have no idea what this little groundcover is. Any suggestions? I do know that under that tree it is perennial.

Of course, it isn't only live oaks that afford some freeze protection. This Blue Daze is sheltered by the lorapetalum in the background but just a few feet away ten more Blue Daze are all top-dead:


If these plants all thrive this winter, my azaleas and holly ferns had better watch out... Zone Ooh-La-La will be moving on in!

Christmas Cheer Charleston Style

Poinsettia in Charleston

While we winter weather wimpy Charlestonians were turning our thermostats up and complaining about a few hours of freezing temperatures, this garden poinsettia maintained its focus and was thus able to pull off a few blooms just in time for the holiday season. Now as anyone knows who has ever mistreated their brand-new florist poinsettia, they don't like the cold, much less a freeze. But this poinsettia was protected from the freeze by the top-secret frost protection gizmo of....

Deep eaves

very, very deep eaves that kept white frost from settling on the leaves. Lots of tropical plants in Charleston that were unlucky enough to not have such protection were knocked back by freezing temps a couple of weeks before this picture was taken. The old Navy base where we found this plant has been closed for years so it is pretty safe to say this plant has been neglected.

We both remember when there were several poinsettias in the ground in downtown Charleston which for the most part, modern landscaping has eliminated (the plants, that is...not Charleston). And that is quite a shame as poinsettias are part of Charleston history. Their discover, Joel Poinsett, was born right here. He served in a number of political roles including being our first minister to Mexico (that was an early form of ambassador and yeah, I had to go googling for that detail) which is what he was doing when he found this member of euphorbia family growing in southern Mexico.

I think the moral of this story is to experiment with planting some marginally hardy plants under hard shade in the form of an overhang, an evergreen tree like a live oak, or even an evergreen shrub. I'm obsessed with the topic of frost protection right now so stay-tuned...more to follow.