A Northumberland Alpine Gardener's Diary
This entry: 22 April 2007 by John Richards
Northumberland Diary. Entry 33.
May in April
I have just returned from a week away, firstly to the North Midland (Chesterfield) Show, and then to Reading, with a sojourn visiting gardens, including those of our Editor and of a past President, in East Anglia. In common with most of the country (England that is, not Scotland), south-east England has enjoyed three weeks of unbroken sunshine, with no rain since March 29th. Not surprisingly it has been very warm, temperatures in south-east England rising to above 20C on most days, and despite high pressure weather in April, it has kept moderately warm, or at least frost-free, at night.
All this has resulted in the earliest mid-spring I can ever remember, at least in the south. As a child, I can remember being told why hawthorn (Crataegus monogyna) has the alternative name of 'May' despite flowering in the first half of June, due to the calendar being put back three weeks in the eighteenth century. This year it is flowering in April!! There is evidence of ridiculously precocious flowers throughout the south-east; cistus, wisteria, lilacs, wayfaring tree (Viburnum lantana) in the hedges, and many more. With the exception of the still-gaunt ashes (Fraxinus) the trees are in full, glorious, May leaf, and the horse-chestnut candles are in full bloom. It was all very beautiful in the unbroken spring sunshine, but I frequently heard the lament 'there will be nothing left for the remainder of the spring and summer', and, more pertinently, 'what will be left for Chelsea?' (still a month away!).
So it was a relief to return to a cool and cloudy north-east, even freshened by light rain, although far more rain is needed and the forecast is not optimistic. During the warm intervening week, many of the mid-season rhododendrons had come into bloom, and I shall start with a selection of three. First the lovely Taiwanese Rh. pseudochrysanthum, (beware that this flowers sparingly if at all for the first ten years of its life, but is unstinting from then on); then the early yellow Cox cross 'Chikor' (still the closest to its exotic and wayward parent Rh. ludlowii); and finally the supposedly tender hybrid 'Fragrantissimum'. I tried to grow the latter in a conservatory for some years, but finally despaired, put it out in a sheltered spot, and it has never looked back in our new, changed, climate.
And some primulas
In many peoples minds, rhododendrons are inevitably linked to another great genus which has shown amazing adaptive radiation in eastern Asia, Primula. The first species shown here, P. forrestii does indeed hail from western China the centre of diversity for both genera. Unusually, it comes from limestone sites (in the Yulong Shan) which are dust-dry before the monsoon arrives. Not surprisingly, it is intolerant of outside culture here (I have heard different stories elsewhere in the country), but is a straightforward plant for the alpine house.
Primula verticillata is also yellow and Asiatic, but otherwise could scarcely be more different. This is one of the so-called 'desert' primulas, but although it comes from the Asir mountains of Saudi Arabia and the Yemen, it actually grows in wet places in shade, often next to waterfalls. It is best grown under cold glass in the shade, with liberal watering when in growth. It is probably not hardy to frosts below -6C. It is perhaps best known as a parent of the hybrid species P. kewensis, but is a beautiful species in its own right.
Very few of the multitude of new primula species that have emerged out of China in the last decade have persisted in our gardens, but P. maximowiczii has been a pleasant and surprising exception. Originally available in a range of downright odd colours (khaki, cafe-au-lait and apricot), luckily it seems that this bright red form, stabilised by Ian Christie, is the plant that has come to stay. I cover it in winter here (planted out in a shady, humus-rich bed) but in the Newcastle University Botanic Garden it has survived well uncovered.
Finally, a European primula. I don't claim this as a good garden plant, but I am pleased to have flowered it. Seed of Primula spectabilis was collected in July 2003 from the Daphne petraea country west of Lake Garda. Planted out in a hypertufa-covered trough, it is flowering for the first, and very probably last, time (this Arthritica group grow well, but flower poorly).
Bleeding hearts and others
Staying with the epithet 'spectabilis', here is a much more showy garden plant which is easy and reliable here and for most other people.
Last week I showed a number of daphnes in pots, but here is a good hybrid, D. x susannae 'Tichborne' grown in the open ground (in fact in a mat of Azorella trifurcata which it seems not to mind one whit, and which protects the roots from summer heat). This is one of the excellent range of hybrids that Robin White produced and which are named for the beautiful villages in his part of the Hampshire countryside. It is a sister seedling of the more vigorous 'Cheriton' which I also grow.
To finish, here are two photos of the later Erythroniums that are at their best now. Interestingly, this is a genus that seems to flower at the same time, irrespective of heat or climate, and many were flourishing in southern gardens last week as well, not least that excellent garden plant E. californicum 'White Beauty'
The yellow 'Pagoda' is a fine, robust, but sterile hybrid, which needs to be divided if it is to spread around. This is best done as the leaves emerge from the ground. Much less vigorous is the Oregon species E. hendersonii which is a delicate lavender shade, usually with a dark, pendant centre to the flower. Grown from seed, I have found a position between old logs that seems to suit it.