A North Wales Alpine Gardener's Diary
This entry: 23 May 2013 - Entry 5 by John Good
Stop-start, topsy-turvy spring!
What a roller-coaster of a spring this has been! Just as we thought it had finally arrived at the beginning of the month, when we had an uncharacteristically warm and sunny Early May Bank Holiday weekend, with new growth and floral delights bursting forth everywhere, the skies turned cloudy again, the wind returned to the N or NE and the temperature plummeted, so that now on the 23rd of May we are back where we started in late April, with daytime temperatures fluctuating between 8 and 12 degrees celsius, and near frost conditions at night. The upshot of it all is that we are still approximately a month behind in the garden, with the last of the late-flowering daffodils still hanging on, and tulips of various sorts still in fine fettle, and some (T. batalanii, T. orphanidea) still in bud.
What has been particularly noticeable has been the wonderfully free flowering of many shrubs, especially all sorts of ericaceae, which obviously loved the cool, damp growing season last year. Here are a few dwarf (or in some cases dwarfish!) rhododendrons that hopefully make the point. Rh. 'Bryn Mair' perhaps requires a bit of explanation as it is a chance hybrid that turned up in our last garden (Bryn Mair) and which has not left home yet so can't be purchased. It has Rhododendron racemosum in it's parentage, but of more than that I am not sure. Anyway, it is, as you can see, very free-flowerting with pale pink fading to off-white flowers. The others shown are R. primulaeflorum 'Doker La' (pink daphne-flowered species), R. sargentianum (yellow daphne-flowered species), R. keiskei 'Yaku Fairy' (pale yellow), R. 'Scarlet Wonder', R. 'St Tudy' (blue). There are many more, some of which have yet to flower, some of which I will show you in next month's offering. All are extraordinarily easy to grow if you are on lime-free soil and are very long lived, but prune them back regularly to prevent them becomineg 'leggy'. If this is done after flowering the prunings can be used as semi-hardwood cuttings, which can be struck in a peat/perlte or peat/gravel compost without the need for heat or hormones, just place the container they are in somewhere away from direct sun, and mist occasionally to prevent them drying out. You should get quite a few to root before the autumn, although some species/hybrids root better than others, when they may be potted up and will hopefully flower 18 months later.
Among other ericaceous plants that have flowered well are the cassiopes, which are among my favourite dwarf shrubs. They love peat (I know that's a non-PC thing to say now, but in this case it's true), although any rich organic matter is better than none. In the old days before our consciences were pricked, the best plants were almost always seen growing in peat blocks, often migrating from the soil in which they had been planted into the blocks themselves. Anyway, give them what organic matter you can and make sure they don't dry out, and plant them in a position in which they will get at least a fair amount of light as in full shade they grow well but flower sparsely if at all; a spot on the N or E side of a building is good where they get early morning and/or evening sun but not the full heat of midsummer sun at midday. Propagation is as for the dwarf rhododendrons just described, although you may be lucky and able to find ready-rooted pieces that can be pulled off and nursed in fairly dense shade until they have produced potfuls of roots. Illustrated below is a 20 yr old plant of Cassiope ''Randle Cooke', a hybrid between C. fastigiata and C. lycopodioides, growing in a semi-shaded raised bed. This plant is named after one of the most famous (although paradoxically least well known, because he was reclusive) gardeners of the 20thC, who lived at Corbridge in Northumberland and whose garden was rescued after his death by a group led by our Northumberland diarist, having been bequeathed to the University of Newwcastle. In 1980 most of the choicest plants were moved to the University of Newcastle Botanic Garden at Moorbank in the centre of the city.
Like most gardeners, and not just those who focus on alpines, I love pulsatillas. They are to be the subject of an eagerly awaited, soon-to-be published book by our former AGS Editor, Dr Christopher Grey-Wilson, It will be nice to have a reliable monograph to hand as some of the naming of plants both in gardening books, nursery catalogues and seed lists is, shall we say, inconsistent. Of the thirty or so species I grow perhaps a third, and all of them are nice. Of course, our native pasque flower (Pulsatilla vulgaris) in all its varied colours and flower forms is among the very best, personally I prefer the dark purple form that is generally that found in the wild. But even this sumptuous flower has to give way in the beauty stakes to the best pale ice-blue forms of P. halleri in cultivation, that are often labelled 'Budapest' or 'Budapest Blue', or more accurately 'Budapest Seedling', most having been derived in that way through many generations from the fabulous plants grown in her Irish garden in the 1920s by Mrs Dorothy Garton, from seed she collected on Suab Hegy, a mountain west of the city. It is not only the flowers that are so exceptional, however, for the foliage is exceedingly hairy, setting off the blooms to perfection. Of course, if you have one of the very best forms of this plant as I believe I do (see below), having received it from my good friend Ron Beeston, you will want to propagate it vegetatively, and pulsatillas being tap-rooted plants this is best done by root cuttings, which may be taken in spring or autumn. If the plant is growing in a pot obtaining root cutting material is easy, if in the ground you will need to excavate around the roots and remove some strong thongs that can then be cut into sections about 5-7 cm long. These are placed upright in a potful of gritty compost with their apices just below the surface, and topped off with grit. Water well and place in a frame or propagator and with luck in time you will see new growth emerging from the tips of the cuttings, when they can be potted up. If lineage is of less importance, pulsatillas are generally easily grown from seed, but this looses viability quickly in store so is best sown fresh. I sow it on the surface of a normal seed compost and cover with a thin layer of grit.
Another of my favourite pusatillas, given to me by another good friend and great plantsman, Peter Erskine, is P. ambigua. The two seedlings he gave me vary slightly in colour, one being almost pure white on opening, the other pale pink, both of them maturing to a darkerr pink, and as in P. halleri, enhanced by silvery-hairy foliage.
This lovely plant of P. slavica (?), alas no more, decided to sow itself into one of the consolidated gravel paths in the alpine garden, where it grew much more lustily and flowered much more freely than its parent which I had lovingly planted in specially prepared soil in an adjacent raised bed!
And my final pulsatilla to entice you on this occasion is the yellow, acid-soil-loving form of the lovely white P. alpina of the Alps, which usually grows on alkaline soils. It is variously labelled P. alpina ssp. lutea, P. alpina ssp. apiifolia, P. apiifolia or even P. sulphurea. Whatever the name, it is a lovely plant, but it is not easy to grow, needing care at the seedling stage when it is easily lost if kept too wet or too dry. Once you have a seedling growing well in a pot, plant it out in rich, well-drained, lime-free soil and leave it alone - pulsatillas do not like being disturbed!
Paeonies and their problems
My dear late mother loved peonies, and so do I. She grew many of the hybrid doubles and Kelway's catalogue was always somewhere handy in our house when I was a child. My preference is for single flowers and for peony species, and I have grown many over the years, almost all of them from seed, which is sown as soon as I get it as the seeds are fleshy, oily, and therefore of short viability, particulalrly in storage. Don't expect anything to appear above ground the season after sowing as the general rule is that peonies show epicotyl dormancy, which is to say that when the seed germinates it produces the seedling root (hypocotyl) but the seeding shoot (epicotyl) remains dormant until a further winter has passed. This two year wait for above-ground confirmation that germination has occurred can be reduced by giving the seed alternating periods of warm and cold treatment. After sowing the seed in pots in damp compost (or placing it in vermiculite moistened with boiled water in a loosely sealed bag), place it in a refrigerator for 6-8 weeks, which should stimulate the hypocotyl to develop. Then move pots out into normal outdoor conditions (or equivalent temperatures) for 8-16 weeks, or if in vermiculite pot the seeds before doing the same. Then return the pots to the refrrigerator for a second 6-8 weeks of chilling. Finally, remove and bring back into normal growing conditions when, with luck the epicotyl will develop. The seedlings should flower 2-3 years later.
Peonies are generally pretty free of pests and diseases, apart from Peony blight caused by a specific pathogen, Botrytis paeoniae, which causes distortion of the leaves and flowers and can severely stunt or even kill plants of all ages (see photograph below of P. mlokosewitschii so affected). Some growers seem fortunate enough never to encounter this disfiguring and potentially leathal disease, but it certainly has a strong foothold in my garden. Some species (the aforesaid P. mlokosewitschii, P. cambessedesii, P. whitmanniana, P. mascula, P. obovata 'Alba' among others) seem to be particularly susceptible, others (P. officinalis, P. lutea, P. delavayi, P. woodwardii) less so. I used to spray the plants with fungicide twice as they developed in spring, along with the roses and fruit trees, but latterly I have given up spraying anything in the garden with pesticides and have learned to live with the consequences. Actually, Peony blight seems to be less agressive this year than for several years.
Below, in the order shown, are P. lutea var. ludlowii (particularly good this year), P. delavayi, P. obovata var. alba, an unnamed red species from the Caucasus (where naming is confused), and a 'blowsy' red P. suffruticosa seedling. Last but not least the Lazarus-like P. ostii that I showed in an apparently near-death condition in the March diary entry following the prolonged frost and cold winds we had suffered..
There are so many more plants I could talk about at this time of year but I have decided to finish off this entry with a visit to one of my favourite places in North Wales for wild plants, the cliffs and western heaths of Holyhead Island on Anglesey. On one of the few lovely sunny days recently we went for a picnic to South Stack, and the plants on the cliff tops, especailly the spring squills and thrift were fabulous, while the occasional chough calling overhead as it rode the wind currents rising from an (almost) sapphire sea made paradise seem near at hand.