Saturday, April 3, 2010
"Do not put your rock garden under deciduous trees' is good advice, and I should know. I have just spent a long day carefully removing last summer's maple and oak leaves from my rock garden, and I'm not finished.
But sometimes good advice just can't be followed. When I started making my garden here, not only was the spot under these trees the only place where I could put a rock garden, but also a rock garden was the only thing that could go there. It is to the South and East of the house, and is basically a large granite outcropping. On the top there are a number of maples, probably all Red Maple, and one very old but still healthy Red Oak. The area slants down to the driveway and the Sampler Garden. The rock is mostly pink granite, but part-way up there is a long ledge of what I think must be limestone. It very much looks like it was once the edge of a lake or something. Some of the granite has fractured and the pieces have tumbled down, so the rock garden is basically on a large pile of broken rock.
Over the years, the leaves and needles from the trees have built up a bit of soil on top, and a few interesting plants have established themselves. There is a lot of Rock Polypody, Polypodium virginianum. It gets a bit dried out in August, but the rest of the year it is a crisp light green ruffle along the North-facing ledges. One good rain in the fall and it revives completely. What it lives on is hard to understand - there seems no soil at all under the plants. The easiest, in fact almost only, way to move this fern to a new spot is to move an entire rock with it already on it. I've tried transplanting it, and had no luck - I think pulling it off the rock damages so many roots it can't recover. It does grow on the ground in the woods in a few places, though.
Partridge Berry, Mitchella repens, also grows happily on the granite. In one spot quite a large patch drapes over a rounded boulder, its little dark green leaves a sparkling contrast to the pinkish rock. In the spring it is covered with its tiny white flowers. They aren't large, nor are there a great many, but they have real presence. Then of course the berries which appear in late summer are a spectacular red against the green. It's not hard to grow in a shady spot, wanting only good drainage and not too many smothering leaves lying on it over the winter.
The other thing that has really set itself up for happiness on the rock ledges is some species of raspberry, but since I can't say anything good about it, we'll not talk about them.