A Northumberland Alpine Gardener's Diary
This entry: 01 August 2014 by John Richards
Northumberland Diary. Entry 279.
Last week our group of local botanists were lucky enough to be invited by one of our participants, Kath (who works for Natural England and changes her name tomorrow, congratulations Kath and a happy future!) to resurvey Cetry Bank, below Widdybank Farm in Upper Teesdale. Some time before the Ark, in the early '70's when Cetry Bank was not yet part of the NNR, as an enthusiastic young sprog I helped teach undergraduates in this Botanical paradise. I had not been back since (although to Widdybank and Cronkley Fells many times of course). I suppose there are few lovelier places in England on a fine July day, and certainly not many so well-endowed, botanically. Here we are, counting populations of Gentiana verna, Primula farinosa, Bartsia alpina and other goodies. Across the River Tees in Yorkshire lies Cronkley, while Widdybank stretches to the right of the picture.
Look left (east) from the same place and the Tees runs down the valley, Cronkley on the right.
The river bank itself is interesting, with juniper, and interesting willows. Here is the net-veined willow, Salix myrsinifolia, which is lovely with the sun shining through. Often the petioles and young twigs are blood-red.
This late in the year, particular in the most forward summer I can recall, not a great deal remained in flower, but the late-flowering Saxifraga aizoides was at its best. This bonny plant is rarely grown, perhaps because it seems to like running water.
The birds-eye primrose, Primula farinosa is abundant, and a few were in flower. I was very surprised to see two with stemless flowers. There is a population of this species on a little-frequented part of Cronkley Fell, 90% of which have stemless flowers. These were part of a study by a former student, Liz Arnold, who showed that the characteristic was controlled by a dominant gene, and as a result I named this distinctive variety P. farinosa v. nana.. Interestingly, these plants are less heterostylous (pin and thrum flowers) than normal ones, and the stemless gene is located on the same chromosome as those controlling the mating system. Such plants have not to my knowledge been seen away from Cronkley before, although the present site is probably less than a mile distant as the raven flies.
I am enormously impressed by Dicentra 'Bleeding Heart' which I acquired in the spring. Like 'King of Hearts', which I have grown for some years, this is a D. peregrina hybrid, but it is much smaller, less vigorous and closer to that parent, with leaves in particular which look very similar. Purchased with a few flowers evident, it has come into flower again, and this time the shocking blood-red flowers are shown to full advantage. I am growing this in full light in a sand-bed, and it has settled down well, although it has yet to face a winter. If it proves reliable, it will be one of the great introductions of recent years.
Here for comparison is Dicentra 'King of Hearts' which I grow in a woodland mix in one of the 'D' beds to replace the snowdrops when they die down. Quite a different sort of plant, but very attractive, long-flowering and reliable.
Next to 'Bleeding Heart' is a Lewisia, which I am also very impressed with. It seems permanent, having survived two winters in a sand-bed without protection. It is not fast-growing, perhaps due to the spartan fare, but it has flowered non-stop for two months or more. I acquired it as L. columbiana 'Rosea', but think it is probably a L. columbiana x cotyledon cross. No doubt the lewisia-wallers will tell me in due course. In any case it has the inestimable value here of flourishing outside without protection, which L. cotyledon won't. However, after experimentation, I am finding a number of lewisias which will grow well outside here in sand, including L. longipetala, L. nevadensis, L. 'Carosel'and L. 'Little Plum'.
I have mentioned Satureja parnassica before. It is an excellent late-flowering ground-cover here, totally hardy and long-lived. At times I have wondered if it is merely a form of S. montana, but it is an excellent match for S. parnassica which seems to be the best name for it. It is quite a local Greek endemic.
It is nearly a year since I built the most recent of the sand-beds, below the alpine houses. This bed had become overrun with several subjects, including a large mass of the lovely Zauschneria angustifolia. I lifted this with a heavy heart, as it seems to largely lack proper roots, running around by means of woody 'strings', and I was very much less than sure that I could propagate it. Most bits were inserted vertically into small plastic 'long-toms' in a sandy mix and placed in a cool place. I am happy to report that about half rooted, and indeed some have already gone to new homes. I have put one back in one corner of the newly refurbished sand-bed, where it seems to have settled down, and is now coming into flower. It is a particularily dry spot, in full sun and pumped dry by a very large Cistus ladanifer.
I am delighted with Saxifraga cotyledon. The original plant, donated by Beryl Bland, flowered a few years ago, but by then several of its offsets had been rooted. I have planted both walls and vertical sand-beds (of which more in a second) with these and some have now grown to an impressive size. S. longifolia seems not to like me too much, so this is a very acceptable substitute, different in character, but in its way just as impressive.
As I said, some are in a vertical sand-bed. If this seems a contradiction in terms, or meiosis, well I do seem to have such a gravity-denying structure. I suppose the fact that it is north-facing helps, so that the sand never dries out, and it is not really vertical of course, although I suppose the slope might be 70 degrees. I guess there is a danger that in a real deluge there might be a mini-sand-slide, but it hasn't happened in more than a year, and we have certainly had some deluges, not least this morning when we gratefully received about three centimetres. I shall stop watering forthwith!
Should one take the plunge?
July was as hot and dry a month as we have enjoyed for many a moon. Outside things have been largely fine in this cool shady garden, although as stated above, I have watered a good deal with an 'up and over'. The alpine houses have been another matter, and although the cooler one has coped quite well, I have largely emptied the hotter drier one (except for the bulbs which are due a repot shortly).Many pots, mostly European Primulas, and Asian Bullatae species, have just been stuck outside on the north side of shrubs and hosed most evenings. Now that it has rained properly, and seems set to become cooler, I shall think about putting them back in a few days.
This brings me to consider whether free-standing pots are a good idea. I used to plunge all my pots in sand, and in the alpine house I still do. However, over the last couple of years I have taken to just standing pots, especially large plastic ones, outside on gravel, and they seem fine. I have done this with asiatic gentians and now have quite a collection in free-standing pots, and have increasingly also done so with lilies, meconopsis and even soldanellas, primulas and saxifrages. I do think it is important that the pot side (roots) is not exposed to hot sun, and many pots are placed amongst troughs or raised beds to shelter them from being baked. I know that many successful exhibitors have large collections just free-standing outside, and I am inclined to think that this can be much more successful than I thought originally. Of course, winter is another matter, and the pots need to be brought into the floor of the alpine house so that they do not become water-logged and then frozen solid. If the plant is dormant, the lack of light on the glasshouse floor is less important.
The astilbes continue to be spectacular. Here is a distant view along the shaded part of the front garden.