Friday, 28 October 2011

Sunshine after rain

Darmera peltata

Chrysanthemum, lost label...

Serratula seoanei and Helictotrichon sempervirens

Morina longifolia

Helichrysum foetidum, Yemeni form.

Thursday, 27 October 2011

Nerine display at Wisley

Nerine 'Honourable Mrs Wynn' illuminated from above.

Nerine display theatre at Wisley.
In the display area of the glasshouse at Wisley at present is a fine display of Nerine sarniensis and hybrids - a pleasant surprise when I wandered in there today. The majority of the plants are arranged in a colourful display on staging and in various containers, but a nice feature was the use special 'theatres' in which to display individual specimens. In these a spotlight shines onto the flowers, causing their colours to glow and sparkle more richly. On the walls hang a selection of reproductions of images in the RHS collection, among which are a couple of the paintings done by Lilian Snelling for Henry John Elwes of nerines he had bred here at Colesbourne - always nice to see them, even if many of the plants they picture are no longer extant.
Reproduction of a painting by Lilian Snelling of nerines raised at Colesbourne by H.J. Elwes.
Nerine 'Lavandu'
Nerine 'Jill'

Wednesday, 26 October 2011

Bernard Verdcourt, 1925-2011

The 85 family acounts of the Flora of Tropical East Africa written wholly or in part by Bernard Verdcourt will remain his greatest memorial.
The name Bernard Verdcourt will be unfamiliar to most, but for decades he was the doyen of East African botany. He was almost synonymous with the great Flora of Tropical East Africa, of which he wrote more parts than anyone else, spanning the period 1956 and 2005, from his bases first at the then East African Herbarium in Nairobi and later (and principally) at Kew, where he occupied an obscure and deliberately out of the way space. A generalist, he tackled families from Adiantaceae to Vitaceae, and as such his advice and commentary on specimens was greatly valued by all working in the FTEA area (Kenya, Tanzania, Uganda), including myself.
Zehneria ridens Verdc., on Mt Meru, Tanzania in 2009.
While going through my specimens from Kilimanjaro in the mid-1990s there were several that I could not place, and it was to Bernard I turned. One odd little thing he quickly recognised as a Muraltia, a principally Southern African genus with the nearest known sites being hundreds of kilometres to the south: this specimen of Muraltia flanaganii remains the only record for Kilimanjaro and the most northern in its genus. Another puzzle was a scruffy-looking cucurbit of the bryony persuasion: in many ways it resembled the well-known Zehneria scandens, but differed in having enlarged sepals, making it appear as if the flower had ten lobes, instead of five in Z. scandens. I pointed-out the differences to Bernard and after due consideration he agreed that it was indeed a new species, and named it Zehneria ridens Verdc., with my specimen as holotype.  The epithet ridens means grinning or laughing, as Bernard said he could see a toothily grinning face in the arrangement of the floral parts, but this similarity has eluded me.

Bernard Verdcourt's other area of great expertise was in snails, particularly those of East Africa and he cajoled his botanist colleagues into collecting them along with their plants: in my case, a particular species of high altitude snail was wanted from Kilimanjaro. I found a selection and somewhere have his determinations list, but don't know if they included his desiderata. He wrote a great series of papers on snail collectors in East Africa, which, being typically thorough, are an excellent reference source for information on many explorers and naturalists. They are among over 1000 publications in botany, malacology, entomology and the Peugeot marque.

Bernard Verdcourt in old age
(img: Henk Beentje)
Long after he retired he made the journey from his home in Maidenhead to Kew each day, in a very elderly 2CV, and was generally the first to sign in each day. The last time I saw him he was in the Kew library, complaining loudly about the activities of a noted Swiss botanist, 'Bloody Greuter!' Sadly he suffered a stroke not long afterwards and for the past few years has been too incapacitated to work. He died on Tuesday and thus did not live to see the completion of FTEA, on which work started in 1949, but of which only a sparse handful of parts remain unpublished. (Thanks to Henk Beentje, Editor of FTEA, for passing on the sad news, and for a short obituary, information from which is used here).

Tuesday, 25 October 2011

Seeds and services: vegetable breeding at Rijk Zwaan

Salanova lettuce varieties on the Rijk Zwaan demonstration field.
 In previous posts I have sung the praises of the beautiful and tasty Salanova® lettuce varieties from the Dutch vegetable seed company Rijk Zwaan: on Friday I had the chance to visit a couple of the company's sites and learn more about the extraordinary ways in which they are pushing forward the development of new vegetable varieties. Although it is still hands-on breeders who place pollen on stigma, the whole process is driven by lab-based geneticists using innovative techniques to maximise the potential of the existing genes - Rijk Zwaan is absolutely against genetic modification using genes from other organisms. The scale of the operation is extraordinary. For example, every lettuce seedling in the breeding programme has its DNA checked for the genes of interest, using tissue from the cotyledon: if not present the seedling is simply discarded.

Michiel Zwaan
My guide for the day was my old friend and colleague Michiel Zwaan, who works in product development for the company (founded by his grandfather in 1924). First stop was the Rijk Zwaan tomato demonstration greenhouse in Kwintsheul, where the current tomato lines are grown under ideal conditions and where all aspects of their cultivation and yield are monitored, providing growers with the information needed to enable them to maximise their crops. All Rijk Zwaan facilities have strict biosecurity measures in place, so we had to dress in overalls - not fetching, but important.

Tomato plants at the Rijk Zwaan demonstration greenhouse: grown hydroponically, with two stems grafted onto one rootstock, they are trained on wires until they are 9-10 m long, over an 11 month period.

Freshly picked samples of each variety are displayed for easy comparison.

The Rijk Zwaan demonstration field at Fijnaart: how field trials should look.

We then travelled further south, to the Rijk Zwaan centre at Fijnaart, where the laboratories are situated and all work on breeding leaf and field crops is done. After a tour of the lab facilities, which would put those of most universities to shame, we moved out onto the demonstration field where the various crop varieties are grown for evaluation and consideration by potential customers. Immaculate and astonishing in the diversity of varieties of e.g. lettuce and spinach being grown, it was also a beautiful sight.

The rather spooky effect of lettuce isolation bags, preventing undesirable pollination. 

A new crisped red Salanova lettuce.

Red Cabbage Rexoma RZ F1: it's difficult to imagine a more ornamental foliage plant.

Sunday, 23 October 2011

Autumn at Arboretum Wespelaar

Lindera obtusiloba (l), Halesia carolina Monticola Group (r).

View of the pond at Arboretum Wespelaar, a garden planned for autumn colour.
I've spent the weekend at Arboretum Wespelaar, not far from Brussels, where the Maple Society has held its triennial symposium. We had a highly enjoyable programme of talks from an international selection of experts and enthusiasts, plus the usual good conversation and company that one gets at such events, but the real highlight was to walk round the magnificent arboretum on a golden autumn afternoon. Started by Philippe de Spoelberch in the 1980s, when the garden at his home was getting to be overcrowded, it is now one of the most interesting and attractive relatively young arboreta around, thriving under the care of the ever-enthusiastic Koen Camelbeke and his team. A primary interest is the genus Magnolia, but the planting has also been done with an eye to autumn colour, with results that are apparent even in a year like this when autumn colours are poor.

Acer triflorum

Acer palmatum 'Beni Kagami'

Magnolia 'Dude's Brother' - Arboretum Wespelaar has an outstanding collection of magnolias.

'Sorbus' folgneri 'Emiel' - a lovely combination of richly coloured fruit and silver-backed leaves.

A mulch of acorns.

Thursday, 20 October 2011

Safely gathered in

The Colesbourne Park greenhouse: filled almost to capacity.
With the first touch of ground frost yesterday it is a relief to have got all the tender plants tucked away into shelter, either in their pots, or with a next generation propagated by cuttings. As a result, all available space is packed full. The autumn migration indoors is always a much more hasty affair than the leisurely placement outside in early summer, impelled by the threat of frost but postponed as long as possible by the enjoyment of the plants. The garden looks suddenly bereft by the removal of the large pots, though there is still much colour - for a few more days.

Tender perennials for next year, propagated from cuttings in August, potted into 7 cm pots in Sepember. I wish they could be in this state when it's time to pot them up in April!

'still more later flowers for the bees'

Tuesday, 18 October 2011

Self-adjusting snowdrops

Galanthus 'S. Arnott' bulbs with elongated stems to adjust their position in the soil.
 When I was in Washington D.C. last month, I was asked to comment on how bulbs adjust their depth in the soil. It is quite well known that some 'bulbs', including Scilla and Crocus, can form contractile roots that can pull the bulb deeper, and in tulips and Erythronium 'droppers' are formed, with the new bulb forming on the end of  a shorter or longer stem or stolon. The phenomenon of bulbs pulling themselves upwards seems to be less well-documented, and it was this that stimulated the discussion, as some Lycoris bulbs had been observed to be doing so. Back home, with  alot of snowdrop bulbs to prepare for potting and replanting I found, as expected, some bulbs showing evidence of having done just this.

As a snowdrop (in this case) clump develops, a mass of superimposed bulbs is formed, some of which, at the lower edge of the clump, or packed in the middle, may need to 'escape' to a more suitable depth. Unfortunately the clumps were already broken up by the time I looked for examples, so I can't illustrate this. Also, sometimes bulbs become buried too deep by mechanical means, and must also readjust their position in the soil.

On the left is the new bulb formed in the current season, large enough to flower in this case. The new basal plate is visible as a yellowish patch at its base, above the extended stem (now withering) that started at a basal plate at the right of the image. The stem is surrounded by the withered bulb scales from the previous season's growth.
What seems to happen is this: in the previous season (year 1) the bulb must somehow 'recognise' that it is buried deeply, and either while still in growth or shortly after it becomes 'dormant', extends the normal short and compact stem (basal plate) to which the bulb scales and roots are attached into an elongated structure potentially several centimetres long. This can only happen at these stages, because the growth in the current season (year 2), starts at the end of the extended stem. It's the only place a main snowdrop shoot can start from. As expected, a bulb develops from the shoot and is thus attached to a long, now redundant and soon withering stem. The old bulb scales, from year 1 (and possibly earlier) wither away in year 2 and form a sheath around the elongated stem, not around the new bulb as they would if it had formed in its normal position (further proof that the stem elongates at an early stage of shoot development). The new (year 2) bulb lacks these protective scales and thus always appears white (and is prone to desiccation). The result is the very curious morphology shown here, in which a long narrow stem bears a normal bulb at its tip, a few centimetres higher in the soil than in the previous season- the reverse of the 'droppers' mentioned above, but essentially by the same means.

No doubt this process is well-known to plant morphologists, but it has been fun to dissect some bulbs and deduce the situation for myself. Now I must attempt some controlled experiments to study the process as it happens.

Friday, 14 October 2011

A glorious sunny day

Nerine bowdenii 'Marnie Rogerson'

Morning light on Salvia 'Indigo Spires', Dahlia 'Mount Noddy' and Miscanthus sinensis 'Yakushima Dwarf'
 After a long gloomy period the weather has changed, giving us a warm and glowing autumn day in which the autumnal flowers really sang. We are just hoping that the clear starry skies that are following it do not bring a frost.

Crocus banaticus 'Snowdrift'

Symphyotrichum novae-angliae 'Rosa Sieger'

Kniphofia 'Cool Knip'

Grasses with Argyranthemum 'Jamaica Primrose' and Dahlia 'Bishop of Llandaff'

Pelargonium 'Bright Red Blizzard'

The neighbours.

Thursday, 13 October 2011

Mists and mellow fruitfulness at Hergest Croft

Acer pseudosieboldianum: the only maple showing really good colour at present.

A shaft of sunshine (for about two minutes) over Hergest Croft.
I've spent the day at Hergest Croft, near Kington at the western extremity of Herefordshire, as the guest of Lawrence and Elizabeth Banks, principally to look at how specimens mentioned in New Trees have developed. Hergest Croft has one of the finest private arboreta in the country and is full of good trees acquired and planted by successive generations of the Banks family over the past 160 years. In consequence it is always a pleasure and education to go round the grounds; unfortunately it was another rather gloomy day, but at least it had stopped raining.

It seems as if it is not going to be a very good autumn for leaf colour, but berries and fruits are abundant and many are looking good now, as seen here. Preparations were under way for the annual Plant Fair and 'Celebration of Apples' at the weekend, which should be an event well-worth attending.

A very pretty small-fruited Cornus kousa (BSWJ 1230)

Sorbus pseudohupehensis

"Sorbus" megalocarpa - the generic status of these Asian entire-leaved species is far from clear.

Raindrops on Tropaeolum speciosum.

Sunday, 9 October 2011

Good plants on a grey weekend

Vitis vinifera 'Spetchley Red' at Cotswold Garden Flowers: a superbly coloured vine.
Despite dingy, grey weather I've been taking my friend Jim Fox from Seattle around to visit gardens and nurseries. It's been a great opportunity to look at a range of plants that perform well late in the season - and there are plenty of them. Here are a few.

Chrysanthemum 'Posie' at Cotswold Garden Flowers.

Tanacetum parthenium 'Rowallane' at the Garden House, Condicote. Sibylle Kreutzberger told us it should be propagated by cuttings in spring.

Various Salvias and Hydrangea paniculata at Condicote.

The outstandingly floriferous Dahlia 'Oreti Bliss' at John Massey's garden, Ashwood Nurseries.

The herbaceous border in John Massey's garden, with Argyranthemum 'Jamaica Primrose' in the foreground.

Hydrangea paniculata cleverly paired with Nerine bowdenii by John Massey.

Melianthus major 'Antonow's Blue' and Rehmannia piasezkii, at John Massey's.