Just a report for anyone considering an alpine trough. Our is by a north
facing house wall so gets practically no sun at all but no overhead
shade. SW London.

Successes :
Gentiana sino ornata - Flowered well in 2 successive years and is
growing strongly. (always dies when attempted in rock garden)
Saxifraga Kabschia types.- grow and flower well
Erinus Alpinus - a bit leggy but OK
campanula cochlearifolia grows and flower well

Failures
Dianthus alpinus - lanky foliage , no flowers - only tried because I had
spare plants.