Sunday 31 July 2011
Saturday 30 July 2011
|Ligularia 'Britt Marie Crawford' and Helenium 'Sahin's Early Flowerer'
|Iberis gibraltarica 'Betty Swainson' (white) and Sedum 'Angelina' (yellow in foreground): Argyranthemum 'Jamaica Primrose' and Dahlia 'Tally Ho' behind.
|Helenium Sahin's Early Flowerer, Monarda 'Ruby Glow'. Lythrum salicaria 'Blush'. The Helenium and Monarda make a lovely combination.
|Achillea 'Pomegranate' - another Sahin selection
|Salanova lettuce from Rijk Zwaan: delicious and highly ornamental
Wednesday 27 July 2011
Hanburyana is the scientific journal produced by the Royal Horticultural Society, principally as a vehicle for taxonomic notes and records. My copy of this year's issue (no. 5) arrived today and I've read it through this afternoon. There are all sorts of interesting nuggets, as always, but among them are two important longer articles. For bulbous people, John David from Wisley discusses 'Nomenclature of intergeneric hybrids of Zephyranthes', unravelling a distinctly tangled tale in this group of New World amaryllids.
Secondly, James Cullen from Cambridge, a well-known Rhododendron expert, writes on 'Naturalised rhododendrons widespread in Great Britain and Ireland'. In this very interesting article he makes the case that the aggressively invasive plant ubiquitously known as "ponticum", is in fact a hybrid swarm involving R. ponticum (from scattered sites in Europe and western Asia), the eastern North American natives R. maximum and R. catawbiense, and the Western American R. macrophyllum, dating from hybridisation events in nurseries in the early nineteenth century. All the evidence suggests that true R. ponticum is not an easy plant to grow in Britain, being rather tender, so added hardiness from the very tough North American species was desirable. Other work has demonstrated, on DNA evidence, that the R. ponticum ancestors were all from Iberia, where the species grows in small areas of suitable habitat, unlike the much more expansive populations in north-eastern Turkey. The admixture of genetics has left its mark in the morphology of the plants, with features of the different species showing up to a variable extent in individual plants. As a consequence, Cullen has published the name Rhododendron × superponticum to cover all the plants belonging to this swarm. It will take a while to catch-on, no doubt, as everyone is so familiar with "ponticum'" as the name for this thug that is not only Britain's worst invasive plant but also a major host for Phytophthora ramorum.
|Rhododendron × superponticum is undeniably attractive in flower, but a terrible ecological menace.
Hanburyana is published in hard copy in only limited numbers, but its full content is usually available online, though this issue has not yet been posted.
Tuesday 26 July 2011
|Allium ovalifolium var. leuconeurum
The plant grows from a narrow bulb and consists of a pair of leaves and a scape bearing a round head of small flowers. The leaves are broad and pointed, borne on distinct petioles, suggesting those of Ramsons (A. ursinum) but without the rank garlic stink. When broken they are, of course, smelly, but the odour reminds me more of a stock cube than an onion outright. Their most interesting feature is the presence of longitudinal white veins, which make them rather handsome; the lamina is light green now, but it emerges with a red flush on which the stripes are particularly conspicuous. The plant's name refers to both the leaf shape (ovalifolium) and the stripes (leuconeurum). According to Flora of China, the variety is found in forests in western Sichuan between 2800-3800 m. There are several broad-leaved Allium species in China, but only this taxon has white-veined leaves.
|Foliage of Allium ovalifolium var. leuconeurum
The flowers are individually small, but together make up a rounded head about 4 cm in diameter, carried on a long red scape well above the leaves. Although nothing about the flowers is individually showy the combination of red scape, pink pedicels, white petals, yellow anthers and green ovaries is very pretty.
Here it is growing on a sloping bed among other plants: in fact the foliage is under the overhang of an adjacent hellebore but seems none the worse for this shading, suggesting it is well adapted to life on the forest floor. I suspect it would prefer a little more moisture than it gets so I'll split a bulb off as it goes dormant and try it in the humus-rich bed.
|Flower heads of Allium ovalifolium rising above the foliage of Helleborus x hybridus.
Monday 25 July 2011
Sunday 24 July 2011
|Lilium 'Red Velvet': in the old bath planter by the door, twice as tall this year as last and quite magnificent.
|Unfurling frond of Polypodium cambricum Cambricum Group. This is one of the latest plants to produce new growth in the year, but the beautiful fronds remain green throughout the winter.
|Larix kaempferi 'Wolterdingen' - a dwarf larch, acquired in Prague some years ago, and now mounding up into an almost velvety heap of silvered soft-green foliage. It turns yellow in autumn.
|A hybrid between Digitalis (Isoplexis) canariensis and a purple foxglove, raised by Maarten van der Sar at Sahin in Holland. Esentially a shrubby foxglove, it produces a succession of flowering stems through the summer.
Friday 22 July 2011
Thursday 21 July 2011
|Ken Burras and Ben Jones discuss leaf anatomy in Sciadopitys umbellata, one of the first trees to be planted at the arboretum in 1964 and used to supply material for generations of demonstrations in taxonomy classes.
The Harcourt Arboretum was started in 1964 as an adjunct to the University of Oxford Botanic Garden, which, in its small site in central Oxford, lacked space to grow a range of large trees, especially conifers, from which material was required for classes in the Botany School. It was established on 30 acres around a core of nineteenth century plantings on the Nuneham Estate, originally owned by the Harcourt family, and included a bluebell wood as well as the arboretum. It has now expanded to cover 130 acres, including an area of coppice woodland and some large former arable fields (Palmers Leys) that are now being restored to meadowland. To go round it with two enthusiasts and hear both about its past and plans for its future was a huge pleasure.
|Torreya nucifera, appropriately bearing its nut-like fruits, a single large seed covered in a fleshy aril.
|Pseudolarix amabilis, the Golden Larch.
|Picea smithiana: a tree planted by Ken Burras in the early days of the Harcourt Arboretum, now a beautiful specimen.
|Cones of Picea smithiana.
|Lomatia myricoides, a truly hardy Australian member of the Proteaceae, flowering freely and attracting masses of honeybees to its fragrant flowers.
|A leaf of Ulmus laciniata, a Far Eastern Asian species that is extremely rare in cultivation. The two small specimens at the Harvcourt Arboretum were the only ones traced in Britain for New Trees, and they are not really thriving.
|Peacocks have been a feature since the arboretum's foundation, nominal descendants of the Harcourts' birds.
Monday 18 July 2011
|Heavy rain this afternoon
Hugh also mentioned a related pleasure, the scent released by soil after rain. There is a word for this: petrichor, first brought to my attention by the American horticultural scholar Bobby Ward. It's a neologism invented by two evidently classically-minded Australians in 1964, from the Greek petra, rock, and ichor, the fluid flowing in the veins of the gods. They state that it's caused by aromatic compounds from plants being stored in soil and rock being released on wetting, which is presumably why it's so ephemeral. I think of it mostly in conjunction with the rain on parched African soil, a first fine, careless rapture.
Sunday 17 July 2011
|Linaria vulgaris f. peloria
|Normal Linaria vulgaris
|A peloric Phalaenopsis
(img: M. Bishop)
|Peloric Linaria purpurea
A peloric form of Linaria purpurea has been recorded before, but it is an unusual phenomenon. I wonder how often it has occurred in L. vulgaris: I notice some differences between online images, so there may be different clones, but I suspect that this too is a rare occurrence. L. vulgaris is a vigorously spreading perennial maintaining itself by vegetative growth, meaning that it is easily propagated and maintained, whereas L. purpurea is a short-lived perennial at best. Not many people would welcome normal L. vulgaris into the garden because of this rampancy, but forma peloria is desirable for its curiosity and, it has to be said, it contributes a very useful patch of colour. Only one nursery currently offer it it in the UK: this is a plant that should be more widely grown.
|Linaria vulgaris f. peloria at Colesbourne Park
Thursday 14 July 2011
An old stone wall enveloped in Campanula poscharskyana is a common sight in the Cotswolds, and usually doesn't warrant a second glance, but I was struck by the sheer incongruity of seeing it in combination with a King Penguin. This apparently unlikely pairing is at Birdland in Bourton-on-the-Water, which I visited yesterday evening with the Cotswold Pheasant and Poultry Club. The presence of vegetation is not actually anomalous: the King Penguin, unlike its relative the Emperor, lives on vegetated islands in the Southern Ocean, so bleak snowiness is inappropriate. However, according to our guide for the evening, Assistant Head Keeper Chris, the penguins find the Cotswolds summer too warm for comfort and must be supplied with cooling devices, including shade umbrellas and ice blocks. The biggest problem is that the females are apt to lose their eggs when they feel the urge to cool off with a swim, so the eggs are usually removed for incubation and hand-rearing while a floating substitute is provided.
Birdland is not a horticultural destination, but it has a lot of beautiful, lovingly cared-for birds that in many cases are part of an organized captive breeding programme.
|Palawan Peacock Pheasant
Tuesday 12 July 2011
Sunday 10 July 2011
After leaving Caterham yesterday I went a little further west in Surrey to Pyrford, the next village to Wisley, where my brother Tom and his wife Caroline were exhibiting at the Pyrford and Wisley Flower Show. It's a classic village flower show, with stalls and entertainments on the cricket field, tea, cakes and a threat of rain. The horticultural show is held in a large marquee, but exhibits were sadly sparse, as is so often the case. I know it's early in the season for produce, but many more people could enter a vase of flowers or a cut rose or two and fill up the benches.
|The horticultural marquee
|Tom receives the cup
Saturday 9 July 2011
|An ephemeral souvenir
|John Jones and Jim Seymour:
my understanding housemasters.
Thursday 7 July 2011
|Looking across the garden at about 6.30 this evening. Anthemis 'Tinpenny Sparkler' in the foreground.
|Geranium 'Nimbus' and Buphthalmum salicifolium 'Dora'
|Clematis 'Prince Charles'
|Hemerocallis 'Joan Senior' and Lathyrus 'Tillyperone'