A Northumberland Alpine Gardener's Diary
This entry: 12 August 2011 by John Richards
Chinese Androsaces, and a work in progress. Entry 190.
Continuing with more of the wonderful plants we saw last month in western Sichuan and northern Yunnan, I shall concentrate this time on one of my favourite genera, Androsace. Until about 15 years ago, chinese androsaces were very little known and few people had had a chance of trying to grow them. In recent years, seed has become more readily available, and we know that some such as A. mairei, A. wardii and A. mariae for instance are not too difficult at least in their early years, while others such as A. delavayi and A. zambalensis seem to be very difficult in cultivation. Unlike the Europaean aretian species, many seem to appreciate damp conditions, at least in summer, fittingly for plants that suffer a monsoon climate to some extent. Not surprisingly for plants from areas which are much drier in winter, they are best overwintered in the alpine house, so most are probably best grown in pots so that they can be moved around.
We saw nine species on our travels. In many ways the most interesting and confused are the A. brachystegia/A. minor pair, not least because it seems that both can grow together, for instance on the Zhedou Pass and Kangding airport road. Both species form mats of rosettes, and both are very variable in colour, ranging from a deep rose to white. However, they differ in leaf shape and indumentum. A. brachystegia has blunt, even subrounded leaf ends which are hooded, and the leaf margins are glabrous. However, A. minor has acute leaf apices which are not hooded and have ciliate margins, although sometimes it takes a lens to see these hairs well. The first two photos are of pink and white forms of A. brachystegia, and the next two are of A. minor.
A relative of these two species, but easily distinguished by the darker, bluish flowers and larger acute leaves with pale margins, is A. mariae (not to be confused with A. mairei, which is a relative of A. limprichtii, q.v.). We only saw this once, on the high road to Kangding airport, which at 4400 m, is said to be the second highest commercial airport in the world..
Androsace rigida is a relative of A. minor too, but is a much laxer plant which scrambles through woodland or hangs in curtians over cliffs. It seems mostly to be a Yunnan plant and is common on the Zhongdian plateau, but we also saw it at lower levels on the Da Xue Shan.
A couple of distinguished hgih scree plants next. Firstly, the lovely A. delavayi, which we saw on the Hong Shan and Da Xue Shan.
Perhaps the definitive high scree plant, always on limestone, is A. yargongensis. I saw this on the Bai Ma Shan back in 2007, and when we finally got to high limestone on the Da Xue Shan this year, there it was again.
Laxer, white flowered species can be very difficult to name. I think there is little doubt that the plant we saw on the Kangding Airport road is A. limprichtii. This is only shortly stoloniferous, and the oval leaf blades with truncate bases are quite distinctive. It is undoubtedly close to A. mairei, which has another leaf shape. We may have seen the latter species too, but I cannot name any plant we saw this time A. mairei with confidence.
A similar plant we saw near Weng Shui, under the Da Xue Shan is A. sublanata. As the name suggests, the leaves of this rather uncharismatic species are woolly underneath, but glabrous on top. It is distinctly a subalpine.
Finally, the widespread and beautiful A. spinulifera. We found this to be abundant in most woodland sites we visited in Sichuan and Yunnan, and it is not restricted to drier areas as I once thought, but seems to be catholic in its requirements. Curious then that it seems to be so difficult to manage in cultivation. Here it is accompanied by the distinctive leaf of Podophyllum hexandrum, another common woodland plant in this area.
Work in progress
I am writing early on a sunny morning (Saturday), after a very soggy week during which it has rained heavily on most days. As for the second half of the last three summers, the North-East seems to have become trapped by the jet-stream in the path of a never-ending succession of depressions for many weeks on end, so that, together with central and southern Scotland, we have received much more rain than the remainder of the UK. However, every cloud has a silver lining, so that I have not had to worry about watering or delicate Himalayan alpines overheating. Rather, I have been able to get on with a project that has been fermenting in my mind for several months.
In this forum I have noted on a number of occasions that whereas I am on the whole happy with the way plants grow in my old alpine house, which has staging to the ground and automatic watering, the new one, erected six years ago, has been very difficult to manage. This house does not enjoy the benefit of automatic watering, and the plants have been grown plunged in wooden trays which dry out very easily, and freeze solid in winter. This has proved disastrous in the very cold spells that characterised the last two winters. Put simply, three years ago I grew about 100 different bulbs in pots under glass. Of these, only 20 remain!
Consequently, I have resolved to get rid of the old staging, and build myself new staging which reached to the ground and receives automatic watering. The first photo shows the first stages of dismantlement, which shows the structure of the old staging well. Don't do this!!
Having emptied the trays (the dry sand was very dusty, and gave me a cough; I should have worn a mask), I dismantled them (the sides lifted off separately) and stored the bases under the eaves of the house. I have plans for these later. The wood is tanalised of course, and should not rot, even in this monsoon summer. The trays were very heavy, and manoevring them out of the alpine house was hard work!
As can be seen, the trays were supported on breeze blocks, and many of these were in sufficiently good condition to be used to build the new benches (cemented in; no shortage of sand for the mortar!). The eventual height of the plunge will be three courses (about 70 cm). In order that the weight of wet sand within the plunge will not force the sides of the structure outwards, I have deemed it wise to make an outside frame of tanalised 2 x 1 with two cross-braces, and this will go into position once the third course is cemented in, but before the compartment is filled. After that the automatic watering will go in. Luckily, I had made provision for the watering to go to the second house when the original watering system was put in place in house number one, so this will just be a mattering of buying and constructing the extra piping and drip feeds.
I shall report back once this project is finished. In the meantime, I am excited by the prospect of having so much more reliable space under glass that will grow plants as well as house number 1.
There will be no problem in filling the new areas! Large number of alpines are sitting rather forlornly outside in the rain. In most cases, they can stand the sogginess while still in growth, so I have a month maximum to finish the staging and get them inside before they shut down active growth and rot. This brings to mind a wrinkle that might be worth sharing, although only if your garden is, like ours, overrun with Geranium macrorrhizum (I guess a number are!). There is an area which is on the north side of the house, but out of the influence of the overhanging eaves, which received sun (if any!) until about 9 am, and is then in shade for the rest of the day which I have found suits young plants well if they are susceptible to sunburn and overheating.
This area is infested with the white form of Geranium macrorrhizum, a plant I am quite fond of if it does not overwhelm other plantings, and is in a place where the smell is not too overwhelming. I became aware that pot plants placed amongst the geranium seem never to suffer from the usual pests; molluscan damage, aphid infestation, caterpillar damage etc.. So now I put more and more of my oversummering pots there! I wonder, if the smell of the geranium leaves as much as a deterrent for invertebrates as it is for us? Amongst the plants in this photo are young plants of Meconopsis delavayi, M. rudis, Androsace bisulca, A. bulleyana, A. adenocephala, A. integra and others.
Over the years we have learnt to fill our considerable 'summer gap' with consolations in containers, and on the terrace, gazanias have provided some much needed solace (WHEN the sun shines!!).
As has been the case in recent soggy summers, there are signs that the autumn will come early again (cyclamens are starting to flower already, and Acis autumnale!), and at least one resident blackbird has surprised us by munching through most of the berries on Sorbus fruticosa. I hope it gets a tummyache! Other sorbi are scarcely coloring as yet, but I was struck by this combination of two rather rare Himalayan species intertwining, Sorbus microphylla and S. rosea.
Nearby, our Eucryphia 'Nymansay', now eight metres tall, has benefitted from the felling of a lime tree last summer and is flowering more freely than for some years.
Our most reliable late-summer bulb, Allium flavum, is at its best.
I am finishing with one of my favourite alpines. I have long wished to establish that fabulous Greek limestone crevice high alpine Omphalodes luciliae here, but our cool wet summers do not suit it. I have never been able to grow it in a pot, but when Turkish-origin seed became available a few years back, I took pains to try to establish a young seedling in a home-made 'tufa' block buried in sand in the alpine house. The same block has other distinguished inhabitats of some years standing, Jancaea heldreichii and Primula allionii. This was three or four years ago, and the young plant grew very slowly and looked sad at times, but is now well established and is flowering fairly freely. Hurray!
I forgot; one of my favourite late summer combination, by the front gate as people come in; Acanthus spinosus (which thrives in the absence of much direct light), an astilbe, and Astratia major. The three 'As' ! Lovely!