Laura Caddy on Alpine Plants
Although there was still a little snow in shady places there was a good attendance at the first meeting of the New Year. Our speaker was Laura Caddy the curator of the Alpine garden at UBC. Laura started by explaining what was meant by the Alpine region. It generally has temperatures of no more than 10 degrees C in the warmest month of the year and is normally above the tree line. Various sorts of surfaces are found including scree which is generally composed of small stones. Plants that occur have long tap roots. A talus slope has bigger rocks and these allow for crevices which provide a much better growing environment. Boulder fields even better as pockets of soil can occur. These are fertile enough to support grasses and Pulsatilla (Pasque flower) amongst other plants. Alpine plants often have very large flowers in comparison to the leaves which make them particularly attractive and cushion plants are also common. These encourage an increase in temperature inside the cushion. They also resist the wind. Fuzzy leaves also offer weather protection. Although Alpines are usually small plants, they are often woody and more like shrubs in composition. Trees at high altitude become misshapen and they are known as Krummholz trees. Laura showed the meeting examples of Alpine or rock gardens such as Kew and Wisley in the UK which she mentioned have huge staff and the plantings are very labour intensive. The Betty Ford garden at the Denver Botanical garden is considered the best example in North America.
Laura then told us about her work at UBC in their Alpine garden. This garden is arranged by continents and is not strictly an Alpine garden as it contains trees and higher temperature levels. A true Alpine garden can only be obtained in a wet temperate area with the use of a glass house. Laura discussed soils in Alpine gardens and suggested that Sechelt or construction sand works well with no enhancement. Rocks are often used and it was suggested that it is important that they be of the same type or otherwise the garden can look messy. Good light is also important. Laura showed us an area that was formerly a pond, but which had been filled with fill and sand and now houses many Alpines. Laura concluded by discussing troughs which are an easy way to have an Alpine friendly area in a home garden. The UBC ones are made of a Tufa mix. Good drainage is important and plants can be grown successfully using sand only. There are several advantages of using troughs which include being more pests proof and making plant viewing easy. They can also be converted into crevice gardens with the use of appropriate rocks. Laura answered a number of questions at the end of the meeting as the audience had been very engaged with her material.