A Northumberland Alpine Gardener's Diary
This entry: 01 November 2008 by John Richards
Northumberland Diary. Entry 96.
Winter in October
It has been a horrible week weatherwise, something that I doubt anyone domiciled in the UK needs to be told, as the effects of the howling northerlies were spread pretty much country-wide. For a number of days we have suffered cold rain or wintery showers during the day and frosts at night, a devastating combination that has caused many plants to go dormant faster than I, or they, would have liked. At least we had no actual snow here. My wife woke up to two centimetres of snow in a London suburb three days ago, the first October snow in the capital, it is said, since 1934. So far no-one seems to have pointed out that was in the depths of the recession! I pass on rapidly.
Fortunately this cold snap was efficiently forecast, and I had enough time on my hands to bring the remaining plants from the plunge into the alpine houses, and to put covers over the primula beds.
This time I am trying something rather different for the smaller primula fishboxes. Instead of keeping them outside under large frame-lights, I have brought them into the larger alpine house, where I can keep a better eye on them, and where the light is better and the air drier (although not necessarily warmer as the glasshouses get no direct sunlight for the next three months). Many have been propped between the benches and glass supports. This first one features Primula longipetiolata, yet to die down.
In the above photo there are two of this year's seedlings of P. sonchifolia at the back, and a P. kialensis from seed collected at Wolong last summer front left. Here are three more of the containers, with Primula minor on the left and P. chionantha sinoplantaginea on the right.
Here is a final picture, this time of some containers that have been put on the floor at the well-lit end of the alpine house. The nearest plant in the furthest container is a well-developed P. nana.
I have been wondering what to do with my Disa uniflora that was such a spectacular success this summer (see entry for July 6th). It has been sat in the alpine house plunge since then, looking perfectly happy, and has grown quite a bit, so that it was looking too big for its pot. Recently I have kept the compost almost dry, probably wisely because the inside of the alpine house has dipped below zero on a couple of recent nights. Clearly, it will get colder still as the winter wears on. As this is a plant from low altitudes (although up to 1000 m) in the western Cape Province of South Africa, it will rarely encounter frost. 'Hardy Orchids' by Cribb and Bailes recommends a minimum temperature of 4-5C (thus rather belying the title of the book!). The authors also point out that although this is a summer-flowering orchid, this part of South Africa, unlike the Drakensberg, is winter-wet, summer dry, so plants should be kept in growth for the winter. They claim that plants can be repotted at any time of year. Their recommended compost was a mixture of perlite and dried, rubbed sphagnum moss.
In the end I decided to repot and bring the plant inside the conservatory, which never drops below zero. Although I had both the perlite and old sphagnum, I added some rough leaf-mould and Ericaceous compost (the latter apparently coir-based) to the mix and used a somewhat larger crock pot.
Incidentally, I can't understand why these plants tend to be called Disa hybrids as they look exactly like D. uniflora to my untutored eye.
There is very little in flower at the moment, but I thought I would show a close-up of another South African, which seems to share the perpetual flowering characteristic of its relative Nemesia rupicola. This is N. sylvatica. As I have pointed out before both are perennial under cold glass. Unlike N. rupicola, N. sylvatica is self-fertile, self-sowing into the plunge almost to the point of nuisance.
I have realised that I should have checked names in Hugh McAllister's monograph on Sorbus before declaiming on the S. hupehensis group on September 28th this year. As far as I know, my comments are correct, but the names I used are out of date. According to Hugh, the type of S. hupehensis is a sexual diploid. Hugh adopts a wide species concept for sexuals and a much narrower concept for apomictic (non-sexual) polyploids, just as I and others have for dandelions, and others still have done for hawkweeds, alchemillas etc. In this group of sorbus, Hugh accepts only one sexual species, for which the prior name is S. discolor. Thus, S. hupehensis of gardens, an apomict, becomes S. pseudohupehensis.
There is a different problem with the plant formerly known as S. glabrescens, but that too has had to be renamed and is now known as S. glabriuscula. Sensibly, Hugh has stayed with names reminiscent of those with which we had become familiar, so that the new monikers are not too difficult to relearn.
Incidentally, as I said in the original piece, I don't think Hugh is right in separating these two on berry colour. They differ by a number of characters, but both vary between white and pink in berry colour depending on season and time of year.
Perhaps the best of all tree in this group is a garden hybrid between S. discolor and S. aucuparia (rowan) which Hugh has called 'Pink-Ness', after Ness Gardens where it was first noticed. There is a super plant of this at our Moorbank Botanic Gardens in Newcastle, which we open for NGS for the last time this year tomorrow. Pray for a fine afternoon!
I am finishing with our Parrotia at home. I have featured this in other autumns, but I have a fascination for this tree. Maybe this is because it is planted almost against a living room window in full view of where I sit. The ever-changing pattern of reds, yellows and greens is mesmeric at this time of year.