A Northumberland Alpine Gardener's Diary
This entry: 17 February 2008 by John Richards
Northumberland Diary. Entry 63.
Frosty winds made moan
Almost every edition of a National paper presently seems to have an article about how this is the earliest spring ever, how blackbirds are cooing, frogs nesting, daffodils burrowing etc etc at least a week earlier than last year, so that we will shortly be expecting leaves to emerge rather before they have fallen, and spring will be over by Christmas.
Well, not up here it won't! We did have a mild spell last week that brought the snowdrops on a bit, but winter has returned with a series of crunching frosts, -5C, for some nights now. Luckily some early rhodos, Rh. 'cilipense', 'Christmas Cheer' , also Epigaea gaultherioides, had been thinking about flowering, but stopped themselves just in time. In these Ericaceae it is curious how even the most developed bud, fully primed to open, will withstand the hardest frost, but the moment a flower actually opens, it collapses at the mere thought of a zero reading. It is also remarkable how plants with sensitive flowers can tolerate temperatures well below freezing under cover (a frame light for instance), but the moment the cover is removed, the flowers are frosted.
Plants are less tolerant of frost out of the ground, and this has caused me to use supplementary heating in one of the glasshouses over the last few nights, because I know that a number of petiolarid primulas lifted for exhibition will not tolerate frost in this condition.
This brings me to Primula bhutanica. My friend and neighbour Alan Furness has worked hard at maintaining a stock of this tricky plant, by cross-pollinating it every year and sowing the seed. Strangely, only pin-flowered plants remain in his strain, but seed is only set after cross-pollination. Unlike its hybrid offspring 'Arduaine' it is a short-lived plant that does not clump up, but at least it is growable unlike its relative (and the other parent of 'Arduaine') P. whitei.
Devotees of this column (if any) will know that I have a penchant for saxifrages, and this is a good time of year for the flowering of the earliest Porophyllum saxifrages that seem to push forward irrespective of the weather. Although I grow many hybrids, some under glass for exhibition, I tend to find that plants last longer planted outside in troughs. This is where I grow many of the European species, not showy enough for exhibition, but wonderful subjects for naturalistic sites outside.
Since I was young, my favourite species has been Saxifraga burserana. There is something about the size and purity of the white flowers set against red stems and bluish prickly leaves that can be heart-stopping. I grow this in vertical north-facing crevices where it is soundly perennial. The only snag is that the showy flowers can be a target for birds that love to peck at them. Some growers cover the plants with cotton threads or chicken netting, but I prefer to leave them untramelled. In any case, these remedies are powerless against the smaller unseen menace of wood-lice that also like to nibble the petals. I think this variety is 'minor'.
It had been a long-held ambition to see Saxifraga burserana in flower in the wild. Eventually I achieved this by the tunnel mouth on the Slovenian mountain Mangart three years ago next May. Plants close to the road were over flower, but a clump high up was still in good condition.
At least this shot shows that the north-facing vertical crevice is the natural habitat!
I grow about five varieties of this fine species. I think the example figured next must be 'Falstaff'. I grow it in a pot and the label has gone, but from my records this seems the most likely candidate. I wonder if it is pure S. burserana as the books (i.e. 'Porophyllum saxifrages', Horny, Webr and Byam-Grounds 1986) and 'Saxifrages, the complete list of species', McGregor and Harding 1998, publ. The Saxifrage Society' suggest. In my view it may be hybrid with S. scardica. Incidentally, if anyone can name this plant certainly, please post your comment on the 'On-line discussion'.
Talk of Saxifraga scardica brings me to a group growing in tufa in a trough. These were seedlings grown from wild seed collected in northern Greece more than 20 years ago. Some flower later, but this individual is always first. Notice the flowers spoilt by birds! The other species is the Himalayan S. lilacina, never spectacular, but persistent and an important parent to hybrids in this group.
Saxifraga lilacina is perhaps best known as a parent to that wonderful hybrid S. x anglica 'Winifred'. Amongst the most successful grex have been those many hybrids from 'Winifred' crossed with the Himalayan S. poluniniana. These tend to be vigorous and fast-growing, but the poluniniana influence tends to cause distorted flowers. Maybe the first of all these S. x poluanglica hybrids was 'Kathleen' raised by Ray Fairbairn and named after his wife nearly 30 years ago. It is still one of the easiest to grow, but because of its distorted flowers is possibly most attractive at this early stage in its development.
Here is Saxifraga juniperinifolia, that I enjoyed seeing growing with the later-flowering S. ferdinandi-coburgii on the north-eastern Greek mountain Pangeion last May. I obtained this from a commercial source many years ago. I find it needs occasional repropagation, best achieved by taking a bit with a stem and jamming it, rootless, into a crevice after flowering.
Here it is in the wild, well over flower and suffering rather from drought on about May 17th 2007.
I can't resist the temptation of showing S. ferdinandi-coburgii photographed on the same day. Unlike S. juniperinifolia, it was at its best. This species is later in the garden, flowering in late March.