Wednesday 29 June 2011

An under-rated Iris

Iris latifolia - the English Iris.
It is a mystery to me that Iris latifolia, one of the most striking irises, and an exceptionally good plant for naturalizing in grass, is so poorly known and seldom seen. Its common name is even English Iris, derived from a misunderstanding from 400 years ago, when Matthias de l'Obel saw it growing near Bristol and named it Iris bulbosa Anglica, a name that rapidly established itself in botanical literature and has stuck to the present day in the bulb catalogues, at least. It is in fact native to north-west Spain and both sides of the Pyrenees, growing in meadows, so must have been brought to England by traders at quite an early date. The species was known for a long time as Iris xiphioides, but Philip Miller's name I. latifolia has priority and is now in general use.

Iris latifolia in John Sales's garden.
 The bulb is quite large, with a shaggy dark tunic and strong roots: I don't think it likes to be dried out for long, which may partly explain its scarcity in gardens. The shoot emerges in early spring and the long narrow leaves expand until about early June, when they begin to die off as the flowering stem emerges. They're only broad-leaved (latifolia) in comparison with other bulbous irises in the Section Xiphium, such as I. xiphium itself and the prolific hybrid group of Dutch Irises. The inflorescence is about 40-45 cm tall, with a series of broad bracts towards the top, the uppermost two protecting the two flower buds. They sometimes open more or less simultaneously, giving the impression of being one very large flower with double the complement of floral parts (as seen below). The normal flower colour is deep purple blue with white and yellow on the falls, but many selections have been made for different colours, including white, pale blue and variously mottled (though I suspect this a viral effect). A reddish-purple form appears among seedlings in John Sales's garden, Covertside, just down the valley from here, and is rather striking.

A reddish-purple form that appears among seedlings at Covertside.
John Sales, former Gardens Adviser to the National Trust, has the finest display of English Irises I know, in the meadow garden he has created adjacent to his home. He and his wife Lyn have a coffee morning and plant sale each year for charity, timing it to coincide with the flowering of the irises, which were duly admired last Sunday. His are a few days ahead of mine, being a couple of hundred feet lower, but the more modest numbers in my 'long meadow' here are now at their peak and look lovely amongst Oxeye Daisies (Leucanthemum vulgare), Aconitum ferox and Astrantia major. I think it's helpful to grow them in grass, as it conceals the dying foliage somewhat; this year the earlier dry weather seems to have encouraged the leaves to die back earlier than usual, so they're showing yellower than they usually are at flowering time. Most flowers set seed, so although seedlings take several years to reach flowering size it is easy to raise a batch of seedlings. It ripens in August, so this is usually the signal to mow the grass before the autumn bulbs emerge, though of course mowing can occur at any time from now as the leaves have finished their work.

Iris latifolia in the meadow here. The dying leaves need to be concealed by tall vegetation.

Monday 27 June 2011

Quite a buzz

At lunchtime I heard a loud buzzing noise - and then found a huge swarm of bees in the air behind the cottage.

They settled on the eaves...

... but by the time our village beekeeper, George Proverbs, arrived five minutes later, the queen had got in under the tiles and the rest of the swarm followed her in, so they are now ensconced under the roof and we are wondering what to do about it!

Saturday 25 June 2011

Oaks at Chevithorne Barton

The new growth of Quercus texana 'New Madrid' flushes in shades of red and bronze.

Members of the International Oak Society discussing oaks at Chevithorne Barton
The International Oak Society held a study day today at Chevithorne Barton, near Tiverton, Devon, which is home to the most complete collection of different oaks in Britain. It has been put together over the past 25 years or so by Michael Heathcoat Amory, who kindly asked me to join them, enabling me to catch up both with the trees, which I last saw about five years ago, and a lot of friends from home and abroad. There are over 400 different oaks in the collection, including cultivars, ranging from the small and shrubby, such as Q. monimotricha from the Tibetan borderlands, to the potentially enormous, such as Q. castaneifolia, and from the very familiar to the latest introductions as acorns last autumn. As such, it provides an unrivalled opportunity to study the species and their hybrids - oaks are very promiscuous - and begin to get an understanding of what they look like. Since oak foliage varies between the different flushes in the year, and with the age of the tree this is by no means an easy matter. Winter hardiness was also a  subject for much discussion, with some surprising survivals and some sad losses.

The pachydermatous bark of Quercus affinis, a very hardy Mexican species

The death of the former champion Quercus candicans from the winter cold was greatly lamented.

Quercus intricata from the Chihuahuan Desert in the USA and Mexico seems to be unscathed by the low winter temperatures (-15 was recorded).

Quercus lamellosa is recovering after the winter.

Quercus ithaburensis subsp. macrolepis from the Balkans and Turkey is perfectly hardy.

Michael Amory's book The Oaks of Chevithorne Barton  (2009) is the most comprehensive illustrated guide to the genus Quercus in English, and a new website with the same title has just been launched, providing an extremely useful online guide to the collection and the diversity of oaks.

A short trip to Yorkshire (part 2)

The immaculate parterre and border in front of Harewood House.

Delphinium, Clematis and Veronicastrum in the border seen above.

'Opheus' by Astrid Zydower is prominent on the terrace.

A male Great Argus Pheasat in the Bird Garden at Harewood House, scene of many happy youthful visits.

Cornus kousa flowering prolifically in the Himalayan Garden at Harewood.
On Thursday I took the oportunity of being in Yorkshire to revisit Harewood House, near Leeds, a place of annual pilgrimage when we were kids with a West Yorkshire Rover bus pass. The magnificent house lies in a park laid out by Lancelot Brown, with the expected lake and fine trees, and is full of treasures, but I discovered that RHS members have free entry to the grounds in the low season (which ended today) so I forewent the opportunity to go inside and instead enjoyed the gardens, lakeside walk and Bird Garden. A few pictures from Harewood are above.

Afterwards I went back to Harlow Carr to see more of the garden and enjoyed a pleasant visit in sunshine, though clouds were blackening. Luckily the downpour didn't start until I was back in the car after an excellent pot of tea on the terrace outside Betty's tea rooms.

A kaleidoscopic bed of primulas by the beck at RHS Garden Harlow Carr.

Another view of the outstanding display of  primulas.

Valeriana and Allium

Thursday 23 June 2011

A short visit to Yorkshire (part 1)

Common Spotted-orchids (Dactylorhiza fuchsii) and Fritillaria meleagris capsules in meadow grass, RHS Garden Harlow Carr.
Tom Stuart-Smith expounds his vision
for the Woodland Garden at Harlow Carr.
Members of the RHS Woody Plant Committee have been on a two day visit to Yorkshire this week, starting on Tuesday morning with a session at RHS Garden Harlow Carr to hear about and discuss plans for the Woodland Garden. This large and dismal tract occupies 40% of the garden area and desperately needs to be made more visitor-friendly and accessible. Thee RHS has commissioned the landscape architect Tom Stuart-Smith to come up with a concept for the area and he explained this both in a presentation and on the ground. His vision includes opening up vistas into the woodland and connecting the existing open areas of meadow while improving the horticultural opportunities offereed by the site. Any such developments wll come about gradually, but if accepted the concept will provide guidance for the garden's managers over the next few decades.

A lovely inversion of the normal colour scheme: white Allium nigrum above purple Salvia x superba.

Another good combination at Harlow Carr; Eryngium 'Jos Eijking' and Salvia 'Caradonna'
In the evening we were invited by Chris Blundell, a member of the RHS Council, to visit his property at Mount Saint John, near Thirsk, and stay for dinner - a most generously hospitable offer. The grey dampness of the afternoon cleared and we enjoyed golden light in this beautuful new garden, with a stunning view across the Vale of York. Chris Gough, the Head Gardener, and his team, keep the place immaculate: one of the team is a trained greenskeeper, and it shows in the extraordinary quality of the turf, which was almost too fine to walk on...

The terrace garden (designed by Tom Stuart-Smith) at Mount Saint John, near Thirsk.

The swimming pool at Mount Saint John
The vegetable garden supplies produce to the house and the Provenance Inns group of local pubs.

 On Wednesday we held a committee meeting at the Castle Howard Arboretum. This amazing collection, undervalued and largely unknown, was started by the late Jim Russell (formerly in partnership with Graham Stuart Thomas at Sunningdale Nurseries in Surrey) in the 1970s. He developed a strong links with RBG Kew and after his death in 1996 Kew personnel were instrumental in setting up the Castle Howard Arboretum Trust, which looks after it, with management input from Tony Kirkham from Kew, and others. It now serves as a northern outpost for Kew, providing space for back-up collections or more extensive plantings of important material. While still comparatively new, with most trees being comparatively young, the arboretum is showing promise of being a really great collection of well-grown trees for the future: it deserves more support and more visitors.

Members of the RHS Woody Plant Committee at the Castle Howard Arboretum: Tony Kirkham leading the tour.

The beautiful immature fruits of  Pyrus 'Kansu pear'...

...attracted many admirers.
The immature cone of Pinus ayacahuite - a Mexican species totally hardy in North Yorkshire.

Young cones of Abies fargesii var. sutchuenensis

The great palace built between 1699-1712 by Vanbrugh and Hawksmoor for the Earl of Carlisle: Castle Howard.

Monday 20 June 2011

Morning light

A view of the pond and adjacent planting from an upstairs window this morning. At 5 am it was 3oC, which seems excessively cool for midsummer.

Saturday 18 June 2011

Sunshine and showers

Members enjoying the Sawyers' garden.
The wide orbit of the Oxford & District AGS Group took members this afternoon to the garden of Celia and Walter Sawyer, just over the county border at Long Compton in Warwickshire, for our Conversazione. The garden was looking beautiful in the sunshine, but dark clouds gathered and a sharp shower drove everyone indoors for tea (with delicious edibles provided by the committee). At Colesbourne, shower followed shower and wrecked the fete, but for us the sun returned and the rest of the programme - perhaps the most important part, the plant sale - went ahead in dry bright conditions.

Osteospermum and Euphorbia in the gravel around the house.
On the way home we took the opportunity to visit the nearby Rollright Stones, a Neolithic stone circle and its outliers, now rather hemmed-in by a scrappy plantation that obscures the effect it must have had when situated in open countryside with a vast view across the northern Cotswolds. The King Stone, north of the circle, is a monolith situated on a large tumulus and brings to mind Matthew Arnold's lines in Sohrab and Rustum:

The King Stone
And thou must lay me in that lovely earth,
And heap a stately mound above my bones,
And plant a far-seen pillar over all:
That so the passing horseman on the waste
May see my tomb a great way off...
And I be not forgotten in my grave.

Friday 17 June 2011

A mysterious Polemonium

Polemonium archibaldiae - in rather grey weather this afternoon.
Visiting Sibylle Kreutzberger for tea this afternoon I admired, as always about this time of year, her magnificent clump of the plant known to horticulture as Polemonium archibaldiae. It's a fine, robust, very perennial plant standing up to 60 cm, with a mass of soft purple flowers with golden anthers above neat foliage. Not only is it handsome, but it has the advantage of being sterile and continuing to flower for a long period: it really does deserve its RHS Award of Garden Merit. It's not easy to propagate, but I find that the new shoots will root and develop if they are detached from the base of the plant when very young in spring.

P. archibaldiae
in evening light
But what is it? A Jacob's Ladder from Colorado was described as Polemonium archibaldae in 1901 by Aven Nelson, an early leading light in the University of Wyoming and a pioneer of the Rocky Mountain flora, but it was later treated as a subspecies of the common western American P. foliosissimum and the wild plant is probably, at best, no more than a form of this species.  Whether the cultivated plant bears any connection with "P. archibaldae" in the wild is impossible to say without doing a lot more research. I suspect we should really treat this garden plant as a clonal cultivar. The picture in cultivation is muddled by the occasional appearance of a white-flowered plant under this name (always rendered archibaldiae in horticulture,it seems) and although various authorities suggest the purple-flowered plant should bear the name, it's not inconceivable that a white-flowered selection was made of seed from a wild population.

PS (20 June 2011) A cut stem on the desk is releasing a strong scent reminiscent of sweet peas - another good feature of this plant.

Wednesday 15 June 2011

Cambridgeshire rarities

A Lizard Orchid, Himantoglossum hircinum, on the Devil's Dyke.
An overnight visit to Cambridgeshire gave the opportunity yesterday to spend the evening out botanizing with Dr Alan Leslie, who is preparing a new Flora of Cambridgeshire and is intimately acquainted with the county's plants. Our destination was the Devil's Dyke, or Ditch, where it runs over Newmarket Heath. It's a Saxon chalk rampart with associated ditch, evidently originally intended to control access in and out of East Anglia beyond, but now forms a linear island of fascinating vegetation across the agricultural landscape and the racecourse. It has been frequented by Cambridge botanists for centuries, and is well known as an important site for several nationally rare plants, but new species  are being recorded there all the time. Here are a few of the special plants we saw: the Lizard Orchid was the first I had seen in Britain, so a very exciting plant for me.

Fruiting heads of Pulsatilla vulgaris on the dyke: both it and the Lizard Orchid have been known here for centuries.
Much less spectacular; the tiny flowers of Bastard-toadflax, Thesium humifusum, the only member of the Sandalwood family (Santalaceae) to grow in Britain. It is a hemiparasite.

The native British form of Sainfoin, Onobrychis viciifolia.

Rosa × dumalis, the hybrid between Rosa canina and R. caesia.
The occurrence of Geranium sanguineum on the dyke is extraordinary, being very distant from any other native population.

Today's extreme rarity: Fen Ragwort, Senecio paludosus

The only native site for Senecio paludosus - a couple of square yards of ditch by the side of a busy road.