20 October 2014
Primula auricula care
This week I have continued the theme of catching up on jobs which I previously hadn't had time to do. The Auricula Theatre at Allt-y-bela has been one area I've been desperate to get into shape and I'm pleased to have been able to make a start.
The theatre was built for Arne's previous house and was brought
here, along with his collection of Primula auricula, when
he moved here eight years ago. It was built from an illustration
and description in Johnson's gardeners' dictionary of 1877
following the description exactly. Arne also had auricula pots
handmade by Littlethorpe Potteries in Yorkshire also based on the
descriptions found in the book.
Primula auricula originates in the mountain ranges of central Europe where they grow in clefts in rocks. Many of the plants found in specialist nurseries now are hybrids between Primula auricula and Primula hirsuta. It's always a good idea if you have plants that aren't thriving to think about where the species originated from; with plants like auriculas, the cultural instructions can seem like a disconnected list of do's and don'ts until you look at the climate in which the plants naturally grow and then things quickly begin to fall into place.
Like many alpine plants auriculas don't like being wet over winter. In their natural environment auriculas will be covered by a blanket of snow for much, if not all, of the winter, and this covering acts like a blanket of fleece protecting the plants from the extremes of temperatures and importantly from the becoming waterlogged. In horticulture we have created frames to mimic this effect and thus protect the plants from our comparatively mild but wet winters.
The plant's alpine origins also help to explain why ventilation is so important and even guides us towards an explanation to flowering period which coincides with the alpine summer. A natural extension of this also helps to explain the repotting and watering of auriculas.
Traditionally Primula auricula plants are grown in relatively small pots, usually up to 9cm in diameter and plants like to be almost root bound. When you consider that plants naturally grow in rock crevasses then this too begins to make more sense. They like to be kept relatively dry in winter (when they would be under cover of snow) and watered more freely in spring, when the snow would be melting in the mountains.
With all this in mind I set about re-potting our auriculas this week. Many of our plants were in quite large pots and were clearly struggling and the theatre itself was in need of a freshen up and a clean so I did this at the same time.
It was fascinating to see the difference between the plants in auricula pots compared to those in ordinary terracotta flower pots. Those in the specialist pots had faired better - the roots were filling the pots, the soil had retained water but was obviously draining well. Those in ordinary flower pots however had struggled to absorb enough water and some had lost a surprising amount of root because of it.
The growing media, as you might expect, is very important and once again we can look to its alpine origins to guide us. Mountainous rock clefts tend to be gritty, free draining and contain thin, low fertility soils. In order to replicate this environment I used equal parts grit, John Innes number 3 - which is a loam based compost - and leaf mould.
My advice would be to create a mixture that feels right in the hand. You get a really good idea of how a mixture will perform by feeling it and you also add air and fully mix the component parts by getting your hands into it. You also get a sense of the soil temperature and moisture content by delving in.
I've now re-potted all of our Primula auricula and lined the edges of the kitchen garden borders with the wonderful little pots. This is giving them plenty of sunlight and a good water in before they return to their winter quarters in the theatre.
Words: Steve Lannin, Gardener at Allt-y-bela
Photographs: Britt Willoughby Dyer