The 21st – yes, the twenty first – Trials Bulletin from the Royal Horticultural Society has recently been published – and it focuses on Clematis alpina and C. macropetala.

Following a trial at the RHS garden which began in 1997, the RHS has published a bulletin which helps us in a number of ways. For a start, it makes clear the distinction between C. alpina and C. macropetala, with some very clear pictures. There are descriptions and pictures of the sixteen plants which were awarded the Award of Garden Merit following the trial. It also provides a selection guide, going through the plants, from white to pink to blue, specifying their features and flowering season. There are also some confusions over the names which are resolved.

This is a most valuable report, and you can download it free of charge here. And I should mention that because of the certainty of the naming, the descriptions and the excellent photography this bulletin is of value far beyond Britain where it was produced.

For information on the twenty other bulletins produced by the RHS following trials click here.