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Saturday, March 9, 2013

Saxifraga 'Dawn Frost'


Late winter is a colorful time around the nursery when the early flowering Porophyllum or Kabschia saxifrages put on their annual displays.  We are endlessly fascinated by the contrast between the tiny foliage of these cushion forming alpines and their large, showy flowers.  In their natural habitats where they grow tucked in the crevices of rock outcroppings and cliffs, these flowers must act as beacons to early flying insect pollinators.  They certainly draw us in for a daily inspection filled with "oohs" and "ahs".

Saxifraga 'Dawn Frost' in full bloom

One of the standouts this year is Saxifraga 'Dawn Frost' which forms a tight cushion of dark green foliage that is covered with stemless, vivid pink flowers in late winter.  This is the type of choice Kabschia saxifrage that often appears on alpine show benches, its cushion completely obscured by densely packed flowers.    Many dwarf cushion hybrids have been in cultivation for decades and in some cases for well over a century.   'Dawn Frost' falls into the group of recent hybrids having been bred by Jan Burgel in the Czech Republic in 1990.  It is a seedling grown from Saxifraga x anglica  'Winifred', another pink flowering variety.


'Dawn Frost' forms a dark green cushion.

'Dawn Frost' has grown well for us for a number of years and has even withstood a winter or two under plastic in our uncooled hoophouse.  In general, we find dwarf cushion Saxifrages stay healthiest when grown in the open air and these days the Kabschia collection is housed out of doors under a patio-like polycarbonate cover where they have excellent air circulation all year.  'Dawn Frost' has also done very well grown directly in a hole drilled in tufa. Saxifrages grown in the low nutrient environment of tufa develop slowly and maintain excellent compact form.

Flowering in tufa after one winter's growth....

and after the second winter.

A note to locals:  Regular nursery open hours begin on March 14th.  We will be open Thursday thru Sunday from 10 am to 4 pm this spring except for a very few weekends in April and the first of May when we are away at plant sales.  Be sure to check our website or drop us a line to confirm open hours.

4 comments:

  1. What a stunning over-achiever!

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  2. Will this plant survive without winter cover, can it grow out in a raised bed if given the right growing medium?

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  3. 'Dawn Frost' is a vigorous grower but all Kabschia Saxifrages have exacting requirements and are considered challenging to grow, even by experienced alpine growers. While some authorities recommend that they be grown under cover for best performance, we are able to grow them exposed to the elements year-round in our Pacific Northwest climate in optimal conditions. In our garden, they are successful in well-drained troughs or in tufa that is outside all winter and also in our best draining rock gardens when planted on steep slopes or in vertical crevices. I would be hesitant to plant them on a level surface, even with excellent drainage, if it is fully exposed to our wet winters. The sloping site is a key to success.

    I would be very interested to hear about experiences in other climates. We have received reports of summer heat and humidity giving alpine growers fits in Eastern climates. A cool winter or cold winter climate with snow cover is also most likely a requirement.

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