Soil for Dryas, Prim. farinosa and Viola calcarata

[JPB]

They grow on rather alkaline soil, but may grow well on neutral or slightly acid soil?? How can I make the right mix for culture in pots??? I have available: peat, sphagnum, perlite, coarse sand, "mergel" (=calcareous); grit; good potting soil with additional clay, and a commercial product called Seramis. I can measure pH quite accurately.

A general question: I can't find any online info on how to make alpine potting soils.

Thanks, HAns

[tonyg]

Hello Hans
I can only speak from my own experiences, not an 'expert' view.  I can grow Dryas in my sandy garden soil (neutral or slightly acid) and also in a neutral mix in a raised bed.  It likes the free drainage and in the garden has flowered well growing over a low wall.  Early developing flower buds are prone to be killed by late spring frost. 
I have grown both the others in pots.  I think they like a slightly alkaline soil and P farinosa was difficult to keep healthy in summer - too hot and dry here.  I did not manage to flower Viola calcarata but plants grew well for a year in soil/grit mix.  Prone to aphids and slug damage it did not survive the first winter ... my fault perhaps, not too cold but perhaps too dry?

[Maggi Young]

Hello, Hans,
I think if you search the SRGC Forums, old and new, you will find discussion about potting mix ... which is "alpine soil", so to speak. Also, in Ian Young's Bulb Log, he often gives recipe for his compost mix and we use the same mix for alpines and bulbs.

[hadacekf]

Hans,
In my garden grow Dryas octopetala without difficulties in each soil. Primula farinosa is for me a difficult plant, but P. frondosa which is more robust than P. farinosa is an easy vigorous species. Self sown seedlings will often appear.
I believe that Viola calcarata twice in 50 years in the garden flowered.

[JPB]

Thanks for the suggestions. I potted V.calcarata and V. biflora in several different mixes with the ingredients at hand. "Heeled" Dryas cuttings in gritty sand. I'll see what happens and let you know.
Another V. biflora is now growing well in a gritty mix including leafmould (Oak), since i have placed it out of reach of the slugs.

Rather difficult guys those alpines.... Lots of sun needed, but sufficient airflow and keeping the pots cool is not easy. No drying out and no wet feet is difficult too. I'll learn...

Pinguicula ?vulgaris is almost flowering now in a pot with lots of sphagnum, so that's the good news!

Cheers, Hans