Well, this was a very cold, snowy winter for our area of Maryland with a minimum low temp of -2 degrees F and about 2 feet of snow in December and 4 feet of snow in February. We are somewhere in the gray zone between zone 6B and 7A and it has been a hard adjustment for this gardener after our zone 8 garden in Washington, D.C.
As you may recall from earlier posts, I've been experimenting with various types of cold-hardy palms and cacti.
Last summer, I planted several palm species/cultivars of Trachycarpus (Chinese windmill palm) including T. fortuneii 'Bulgaria', T. wagneranius, and T. fortuneii 'Tennessee form'.
Most forms of hardy palms have improved cold hardiness with increasing size and age, but finding mature specimens in our area can be a challenge and shipping from the South can be very expensive.
Of the small, starter palms I planted last summer, none survived. Well, okay ONE did, but I mowed it by mistake because it was so scrawny and pathetic it deserved to die.
The only real survivors were a 3 foot specimen of generic windmill palm I bought at a local nursery and one 18 inch specimen of Trachycarpus fortuneii 'Bulgaria' that I transplanted from our garden in Washington, D.C. 3 years ago. That specimen, originally came from a strain of Trachycarpus growing in Bulgaria that had reportedly withstood temps well below zero degrees fahrenheit. The Bulgarian strain was imported as seed into the U.S. and is intermittently available through Plant Delights Nursery in North Carolina.
There are many nice examples of Trachycarpus growing without difficulty in protected spots in and around Washington, D.C., but we are an hour north of the city, have essentially wide open spaces without much wind protection, and lack the microclimates you see in many city gardens.
This year, I planted THREE 5-7 foot specimens of Trachycarpus fortuneii in the front garden of our farm house, south facing and out of the prevailing winter winds.
I also planted 2 need palms, which are probably the most cold hardy of all palms. There are some very large specimens of needle palm growing nicely in the National Arboretum in Washington, D.C.
Thirdly, I planted 3 small Morrocan blue fan palms, Chaemerops humilis cerifera. While European fan palms are not famous for their cold hardiness, the moroccan blue palm grows at high altitudes and probably has significantly more cold tolerance than its standard Mediterranean cousin. I prefer the blue hue of the Moroccan form, so from my perspective, its a win-win!
I know it doesn't look like much right now, but we saw some beautiful examples growing at high altitude on the road leading out of Marrekesh into the Atlas Mountains in heavy snow and bitter cold.
Moving on in our tour of plants likely to die this coming winter are the 'winter-hardy' cacti and succulents.
For the nay-sayers out there, here's an example of Echinocereus and Agave parryi I planted in some concrete planters on our porch last summer.
These small starter plants spent weeks under 2-3 feet of snow and endured temps into the minus single digits. As you probably already know, plants in pots and other containers above-ground typically endure temperatures the equivalent of a full zone colder than in-ground plants, making these babies tolerant to at least zone 6A or even zone 5B. And they are thriving with many side shoots and new growth!
The secret with the cacti and succulents seems to be absolutely perfect drainage. After several failed attempts, I started planting in straight gravel/stone (i.e. no soil) and have had good results ever since.
Here's an installation of Agave parryi going in with pea gravel - to be top-dressed with another gravel that fits into the bed a little more seamlessly.
I know this is hardly farm related but I thought you might be interested and I will keep you posted next spring as to how my experiment has worked out.