new buds on rose Ducher
Buds and tender new growth (red) on the ‘Ducher’ rose.

November 20th, 2009
Freeze Warning

We Austin gardeners are living in heady times. The last two winters have been very mild. Last year I didn’t even get a killing freeze in my garden (although I know others in who Austin did). As a result, plants that usually die back to the ground–like the duranta and the Port St. Johns creeper–kept growing and flowering year around. Tender perennials that we treat as annuals–such a jalapeno pepper–demonstrated that they are indeed perennials. My aloe vera that I planted outside has survived three winters and grown and flowered. It produces so many pups and is so heat and drought tolerant that I keep planting it all over the garden. And worse, I’ve started collecting its cousins. There are 400 species of aloe and dozens of different ones are available in Austin nurseries. Some are reputed to be hardy but aloe vera is not. So far the aloe vera has reacted to the cold by turning slightly red but recovered quickly.

Aloe barbadensis
Aloe vera. I planted these in 2006. Since then they’ve doubled in size, multiplied, and flowered.

The aloe vera was only the beginning. Last winter I got tired of lugging plants I could barely carry into the house when a freeze threatened only to lug them back out again a couple of days later when temperatures returned to the 70s. So, I planted them out in the garden, too. If Austin gets several hard freezes this year will it be the end of my lemon tree, my cut leaf philodendron, two different kinds of asparagus fern, and my kalanchoe?

Kalanchoe dagriemontiana
The kalanchoe is forming new buds. These will turn to mush in a freeze.

Why do I keep buying new frost-sensitive plants like the allspice bush and the Natal plum?

As I continue planting (Austinites do most of our planting in the autumn so that our plants can have a chance to establish themselves before our deadly summer), I keep wondering if we aren’t headed for a reversal of fortune. We’ve been riding a non-freeze plant survival wave, living recklessly based on short-term memories. The forecast for this El Niño winter is colder than normal.

Established plants have responded to Austin’s recent rains after our two year drought as if it were spring. Several normally spring-blooming plants are flowering now and everything is putting out new growth. Even in normal years, many of our plants don’t go dormant and our ground never freezes. I often have roses in bloom at Christmas. Although on average Austin has a dozen nights of freezing temperatures, these nights are interspersed with days in the 60s, 70s, and even 80s. (If you delight in statistics, see the freeze dates at Camp Mabry between 1997 and 2006.)

Earlier this week, November 17th, the National Weather Service issued its first freeze warning for parts of our county. This should not have surprised us. The average is first freeze is December 2nd and as recently as 2005, our first freeze was also November 17th.

If the garden is unprepared and vulnerable, I think Austin gardeners are even more so. On Twitter, our responses fell into one of three camps: those who hurriedly covered plants and brought them inside, those who decided their plants were just going to have to tough it out, and those who gambled that while a freeze might hit other parts of Travis County, our micro-climate was probably safe. I was in the latter group and I won my bet with the weather. This time.

I need to get prepared. When it comes to Austin weather, anything can happen. In 1980, on the Wednesday night before Thanksgiving, it snowed.

Kalanchoe daigremontiana
2009-02-26. Kalanchoe daigremontiana.

November 6th, 2009
Kalanchoe daigremontiana

Mother of thousands, Kalanchoe daigremontiana, is described as an annual succulent that will not survive a frost. For years, I kept this native of southwest Madagascar potted and moved it indoors any time we had a freeze warning. Last winter, it got too big for me to carry in and out and I left it outside. Although others in Austin experienced hard freezes, my neighborhood just south of Lady Bird Lake apparently did not. Old stands of mother of thousands bloomed up and down my street.

Kalanchoe daigremontiana
2009-03-10. A well established stand of Kalanchoe daigremontiana in a neighbor’s garden.

When taking photos for GBBD last January, I noticed that buds were forming on my potted plant.

Kalanchoe daigremontiana
2009-01-15. Anticipation.

It had never bloomed before and I was excited. It took almost six weeks for the flowers to open fully; however, it remained in flower for months. Flowering does not necessarily happen annually. The conditions must have been just right in Austin last winter because I’d never seen it in flower before, mine had never flowered before, but I suddenly saw it flowering everywhere.

Kalanchoe daigremontiana
2009-03-20. Kalanchoe daigremontiana.

My kalanchoe tolerated full sun even in this hot, dry year. It was fairly drought tolerant. I watered it when it looked reddish and sunburnt but I didn’t have to baby it. When it began to rain and cool down, the leaves became greener and plumper. I would say that its growing requirements are similar to Aloe vera. It’s tempting to want to plant both because they are great structural plants that can take Austin’s punishing summers. They’ve survived the warmer than normal winters we’ve had in 2007 and 2008. However, 2009 is supposed to be colder than average–plants which have recently thrived may be in for a killer surprise.

Kalanchoe daigremontiana
2009-11-06. Kalanchoe daigremontiana. All the green around the pot are baby plants.

Fortunately this kalanchoe is aptly named mother of thousands. The edges of the leaves are covered with plantlets which drop off and root. I got my start by taking a few leaves and sprinkling the plantlets into the pot containing another plant. Sure enough they sprouted and pretty soon took over the pot. Now they’ve sprouted all around the pot

Kalanchoe daigremontiana
2009-02-09. Kalanchoe daigremontiana.

The stems also flop over and root. I’ve read that the cuttings must be kept dry to root but I haven’t tried that yet because when the rains finally arrived this fall hundreds of little plantlets fell from the leaves and took root around the mother plant and even quite far away wherever the rainwater had washed them.

I’m potting them up to take inside over the winter as a backup in case the mother plants freeze. If you’re an Austin gardener and want some, let me know.

Pronunciation: kalənˈkō-ē, that is the “ch” is pronounce like a “k”. “ko-ee”, not “cho”.