Wisley's Alpine Diary
This entry: 04 March 2010 by Paul Cumbleton
Log 68 - Saxifrages
Wisley's Alpine Log
By Paul Cumbleton
2010: Log 68 4 March
I ended the last Log by showing a few pictures of saxifrages. After this I was asked if I would write more about them and say how we grow them, so this log is devoted to these plants. More specifically I am writing about those saxifrages within the Porphyrion section which includes those we familiarly call the kabschias and englerias. I?m restricting myself to describing how we grow them and illustrating a few, but you can of course find a great deal more information from the Saxifrage Society ? see http://www.saxifraga.org/
Above: Saxifraga 'Allendale Elf'
Cushions covered in flowers such as in the above photo are of course the great attraction of this group of plants. With hundreds of cultivars and hybrids to choose from, in an ever increasing range of colours and shades, they constitute an indispensable part of our alpine spring. We grow them in all kinds of situations ? in pots, raised beds, troughs, in tufa, in sand beds and out on the rock garden.
Our potted collection of these saxifrages is cultivated by Kathryn Hart who has provided the information I?m giving about how she does it. I?ll intersperse the details with more pictures of plants we have in flower right now.
For potting, we use a mix of 1 part John Innes compost No. 2, 1 part peat and 2 parts limestone grit dolomitic lime is added to the peat fraction only at a rate of 2.4g per litre of peat.
Above: Saxifraga ?Bohunka?
Kathryn re-pots only when necessary ?i.e. when the plant has reached the edge of the pot and needs a larger one. She does this just after flowering
Above: Saxifraga ?Mary Golds?
Correct watering is essential if you want lots of flowers. From late winter when the buds first start to form, the plants must never get dry. In fact they want plenty of water. From this time and right through summer she waters regularly. The pots are clay and plunged in sand and she also keeps the sand wet through this period ? this means watering the sand every day when the weather is warm. If they get too dry while the buds are forming they will abort, and if too dry in hot weather, the foliage will scorch. Over winter the pots are kept just moist.
Above: Saxifraga ?Claude Monet?
Below: Saxifraga ?Pink Star?
In summer ? in this part of the world anyway ? they must have a little shade if scorching is to be avoided. We remove this in autumn so they get the best possible winter light.
Above: Saxifraga ?Miluj Mne?
The same saxifrage in tufa. The flowers are a bit paler because they are older. This is characteristic of many saxifrages ? the flowers fade as they age.
Too much feeding seems to produce plants with few flowers and lax cushions. Kathryn gives just 3 liquid feeds per year ? a couple after flowering and one in early autumn, using a half-strength, high potash fertiliser on each occasion.
Above: Saxifraga ?Cumulus?
The only other advice is to keep them as cool as you can in summer and give maximum ventilation.
Above: Saxifraga elisabethae ?Milford Cream?
Below: Saxifraga 'Karel Kapek'
Above: Saxifraga ?Galaxie? growing in tufa
Below: Saxifraga ?Peach Melba?
Finally, a few flower close-ups:
Above: Saxifraga 'Wolfgang Johan Goethe'
Below: Saxifraga 'Gabrielle'
Above: Saxifraga 'Jan Neruda'
Below: Saxifraga 'Moravian Karst'
The last one is Saxifraga 'Rembrandt van Rijn' :