A small but dedicated group from Scottish Branch braved the dreaded Cowal midges to visit Benmore Botanic Garden and Kilmun Forest Garden in October.
We were greeted at Benmore by Peter Baxter and two of his gardens team, David Gray and Billy Fowler. Peter introduced the site. Benmore was gifted to the nation by Harry George Younger in 1924. At around this time, the Royal Botanic Garden Edinburgh had been looking for a suitable high-rainfall site for part of its collection, and in 1929 the Younger Botanic Gardens were opened to the public.
One of the main topics of interest at the gardens over the past few years has been the seeming decline in health of the 1863 Wellingtonia avenue; thinning foliage and poor shoot extension were worrying signs that things were not as they should be. The main contributing factor, of course, is compaction as the avenue flanks the main drive to the house, and the carriageway, surrounding grass areas and associated trampling and compaction were affecting the trees’ root function. A campaign was started and money was raised to conduct a three-phase restoration project using compressed air fired through lances to reduce compaction and to produce a more friable substrate. Phase two is mostly complete with the grass area between the trees being reduced to a strip up the middle of the avenue. This area will now be rehabilitated with better-draining, less-compactable material. The trees and surrounding plants seem to be responding well.
Peter Baxter of Benmore Botanic Garden showing Scottish Branch members the site’s Wellingtonia avenue. (All images: Simon Stuart)
Benmore Garden is the largest of RBGE’s properties, and whereas at other sites one or two specimens can be planted, here larger groups of up to 50 target species can be accommodated. The garden holds the national collections of Abies, Picea and south American conifers and has large collections of International Conifer Conservation (IConiC) planting, as well of all five species of Arran whitebeams.
Another feature of the gardens are the four biogeographical areas – Japan, Bhutan, Tasmania and Chile – each with a feature to distinguish them, e.g. a torii gate for Japan.
In the afternoon some of the group carried on to Kilmun Forest Garden, which was gifted to the nation at the same time as Benmore. This site has been managed by the Forestry Commission since 1924, and from 1930s almost 300 different species have been planted in plots of 0.1ha and larger. There are currently around 200 different species within the collection, of which 145 are deemed to be in good health.
Kilmun is an extremely interesting site where species normally seen as individual specimens can be experienced in larger blocks. It has also been useful to observe how different species and varieties perform (or not) on the west coast of Scotland.
There was some discussion about the correct choice of provenance as, for instance, one plot of Abies alba was from Denmark, outside its natural distribution, and this performed poorly when compared to a nearby provenance trial. The timber qualities of Cryptomeria japonica grown at Kilmun have also been poor when tested, prompting questions about provenance. This conversation developed into a discussion about provenance and origin. Just to be clear, origin is where a species is originally from and provenance is where the seed (or vegetative material) has come from, so you can have seed from Oregon grown in France. When the seed is collected from this stand the origin is Oregon and the provenance is French.
This article was taken from Issue 195 Winter 2021 of the ARB Magazine, which is available to view free to members by simply logging in to the website and viewing your profile area.