It is not very often a true innovation in gardening techniques comes along. In fact, the last one I remember was upside down tomato plants several years ago.
That one did not appeal to me, but I visited the site of a new garden in England a couple of weeks ago, and this one was wonderful. Wisley Garden, the headquarters of the Royal Horticultural Society, is close to my sister's home and I look forward to visits there.
The newest attraction at Wisley is a crevice garden. Situated next to the large Alpine Houses, it is a startling feature at first sight. The Alpine features have been there since 1912, displaying potted plants, and they now are overlooked by a greatly enlarged waterfall and this crevice garden.
Basically, a crevice garden is a type of rock garden constructed with thin slabs of rock arranged vertically in a stable base of compost. The crevices between are then filled with potting medium ready for planting.
Slate is a good choice for the rocks, as it is naturally the right shape, but any type of rock is good as long as the shape is right. Wisley's uses sandstone, which must show its lovely golden color in the sunshine. Unfortunately, the sun shone only rarely during my weeks in England, but still the color was appealing.
This garden was designed and built by Czech gardener Zdenek Zvolanek, and a video of his efforts while planting the new garden is on the web at www.rhs.org.uk/thegarden. I found the video by clicking on the second link, Advice/RHS.Home/RHS Gardening, and typing Crevice Garden into the search box.
His recommended soil material is a 50/50 mix of compost and sharp sand or grit, which gives Alpine plants stable growing conditions, room for deep root runs and ultra-sharp drainage that the crevices provide.
The crevice garden at Wisley is very large, probably more than 100 feet long, and about 25 feet in width, but I am assured it is possible to make one's own sample in a container. After constructing the hardscape with the slabs of stone set in the compost mix, the narrow crevices are most easily planted with small rooted cuttings or seedlings. Carefully remove most of the old growing medium from the roots, then make a hole in the crevice with a pencil, as deep as the roots are long. Insert the roots, and firm the new compost around them. After planting, one can fill the crevices with further thin slabs of stone to achieve a more natural look. Stop up the end walls of the crevices in the same way to prevent compost from washing out. Water in the new plantings well, and after that, water and feed as for any other alpines in containers.
At Wisley, there were many species of flowers growing, all small yet, as this is a new garden, but it is easy to look ahead to imagine creeping plants filling the spaces and draping over the stones.
Alpines now have been grown at Wisley for 100 years, and the current team tending the displays is anxious to dispel the myth that alpines are tricky to grow. There is a huge choice of easy-to-grow plants suitable for small containers, troughs, raised beds as well as crevice gardens. I have a number of pictures of the garden I would be happy to share with anyone interested, and I certainly expect to try a small one myself next spring.