Thursday 29 September 2011

Coruscating coleus

in Graham Blunt's garden, Nutley, New Jersey
In my so far quick look at the October issue of The Garden I notice that Nigel Colborn's opinion piece discusses his liking for coleus and the issues of taste in gardening that they raise. Travelling around the eastern states this month I was astonished by the wonderful array of coleus cultivars that are available there and widely used to add great richness to the garden display. As with many sumptuous foliage plants they clearly thrive in the pseudo-tropical heat, humidity and (at least latterly) wetness of the east coast summer and make stunning combinations possible. Such richness and diversity in summer bedding may not be a viable option for us in England, with our cooler summers, but there's no problem growing coleus here. Tasteless? I don't think so.
Coleus is the English name for plants derived from what has been known as Solenostemon scutellarioides, a southeast Asian plant with variably coloured and marked foliage. The cultivars are still often known as Coleus blumei, but botanists now place Solenostemon in the genus Plectranthus, so Plectranthus scutellarioides is the correct name for all these fabulous forms. I was not able to ascertain the cultivar names of most of the clones I saw, so here I've only indicated the garden in which I saw them growing.

around the fountain, Bartholdi Park, Washington D.C.

'Alabama Sunset' in Graham Blunt's garden, Nutley, New Jersey

'Religious Radish', at Wave Hill, New York

at Wave Hill, New York

'Inky Fingers' in Graham Blunt's garden, Nutley, New Jersey

'Red Velvet', at Wave Hill, New York

at Frelinghuysen Arboretum, New Jersey

Tuesday 27 September 2011

Home to an autumnal garden

View over the garden from the new border: Coreopsis 'Incredible, Incredible' at the front.
An overnight flight from Philadelphia brought me home this morning, after three weeks away, to a garden that has changed from summery to autumnal, but is still full of colour and interest. Here are a few snaps, taken on a glorious sunny but fresh day.

Achillea cv, Aster x frikartii  'Wunder von Stafa', Aster 'Freda Ballard' in the new border.

Crocus pulchellus x speciosus

Aster 'Little Carlow'

Colchicum 'Dick Trotter'

Zauschneria californica 'Dublin' and Lespedeza bicolor 'Gibraltar'

Up the garden path in the late afternoon.

Friday 23 September 2011

Wet on the way from Washington to Wilmington

The US Capitol from the US National Botanic Garden
After a few fun and interesting days in and around Washington DC I'm sitting on the Amtrak Acela service to Wilmington, Delaware - though as I type we're at Baltimore station. It's pouring down, a warm and very wetting rain, and my attempt to see the sights of the National Mall this morning have left me very damp. Unfortunately this train is air-conditioned. The horticultural highlight of the Mall is the US National Botanic Garden, in its prime location just below the Capitol. There is a great native plants garden, some very welcome conservatories and the Bartholdi garden (above) has some excellent lush tropical planting.

Tuesday 20 September 2011

News from a far country

Sitting in Bradley International Airport, Hartford, Connecticut, on my way to Washington DC: news comes in an email from my mother that Galanthus reginae-olgae is in flower in their garden. The season has started!

Galanthus reginae-olgae (at Colesbourne Park)

Tuesday 13 September 2011

Horticultural postcards from New York

The High Line - Manhattan's linear aerial park, built on the bed of the former freight train line running through the city, and now a hugely popular public space.
The Empire State Building from the High Line. Oudolfian grasses and perennials are a major feature of the planting.

In other areas the High Line is planted with woodland plants, but perhaps Magnolia macrophylla was not so wise a choice.

Ludwigia sedoides, aptly named the mosaic plant, at Wave Hill.

Lilies at the farmers' market, Columbus Ave.
and heirloom tomatoes...

Apartment gardening: Michael Riley and Francisco Correa's green wall of tropical epiphytes.

Fresh Forsythia at Chelsea Market: how?

Friday 9 September 2011

Delightful plants in North Carolina

Lycoris straminea 'Buttermint'
 I am currently on a lecture tour for the North American Rock Garden Society, which will take me up and down the East Coast of the United States. Opportunities for posting may be erratic and infrequent.

For the past few days I've been based in Raleigh, North Carolina, enjoying the horticultural pleasures of this area. On Wednesday a visit to AJ Bullard, of Mt Olive, introduced me to several interesting new fruits and was followed by an afternoon at the remarkable JC Raulston Arboretum in Raleigh, whose eponymous founder set it up as a trialling and distribution centre for new plants for North Carolinan gardens, a role in which it continues. Yesterday brought a visit to a garden and plant collection that never fails to thrill, Tony Avent's Plant Delights Nursery and Juniper Level Botanical Gardens. It is packed with treasures, both new and familiar, and the focus of extraordinary efforts to bred and select new plants. A fuller post about 'PDN' will follow, but today is Friday, so I must go to New Jersey.

Pueraria trilobata 'Sherman's Revenge' - a splendid variegated form of the dreaded kudzu, scourge of the South.

Monday 5 September 2011

Some early colchicums

Colchicum agrippinum has been in flower since mid-August. It is a ancient sterile hybrid between Colchicum autumnale and C. variegatum and is immediately recognizable among hardy colchicums through its strong tessellation, narrow segments and purple styles.  A superb garden plant.

Colchicum variegatum at Wisley: the most beautifully tessellated of all, but it requires alpine house or bulb frame cultivation in this country.

Colchicum autumnale is a native of much of Europe and in most forms not a particularly special plant for the garden. This is a very pallid clone known as 'Oxford Pale' among enthusiasts, having come from the Oxford Botanic Garden many years ago. C. autumnale is distinguished by having white styles.

Colchicum autumnale 'Nancy Lindsay' has the pale styles of the species it's attributed to, but the rich pink flowers and coloured floral tube make it very dissimilar to most forms.

'Nancy Lindsay' is an excellent plant for planting in grass as here at Colesbourne Park: vigorous and showy but not too large.
Colchicum guadarremense is one of the darker -flowered Spanish members of the C. autumnale alliance, a small and pretty plant.

Colchicum tenorei is reputedly an Italian plant, clearly allied to C. autumnale, but with slight tessellation and purple-tipped styles. This stock has persisted at Colesbourne Park since the time of H.J. Elwes, who supplied the material for its description in J.G. Baker's Synopsis of Colchicaceae (1879).

Colchicum byzantinum is another ancient hybrid, probably between C. autumnale and C. cilicicum: it was sent from Constantinople to Vienna in 1588 and has been a feature of gardens ever since, producing masses of soft pink flowers with broad segments. It has a crooked, purple stigma and the faintest hint of tessellation.

A white-flowered mutation of C. byzantinum, 'Innocence' (sen here at Wisley) was first offered for sale in the early 1980s. It is a splendid plant, being the most floriferous of all white colchicums. It retains the purple-tipped stigma.

Saturday 3 September 2011

A surreptitious snowdrop killer

Large Narcissus Fly larva in a Galanthus bulb
Over the years, in the process of handling large numbers of dormant snowdrop bulbs I have become very sensitive to the feel of a good bulb and a wrong 'un. A good bulb feels heavy and plump, but when there is something amiss it feels different, either light, dry and scaly in the case of fungal disease, or soft and light for other reasons. The most common of these - and it is quite common - is caused by the presence in the bulb of a larva of the Large Narcissus Fly, Merodon equestris. This species, a hoverfly with colouring mimcing a bee, is on the wing in late spring, and lays its eggs around the dying foliage bases of Narcissus and Galanthus (or any other amaryllid). The young larva makes its way into the soil and enters the bulb, not through the neck as often said, but either through the basal plate or through the side of the bulb.

A typically damaged bulb, soft and discoloured, showing the lateral entry hole.
It then proceeds to eat its way through the central portion of the bulb, consuming the basal plate and embryonic shoot, then working through the remaining scales, until it is completely hollowed out. The larva is plumply cylindrical, with vestigial legs, and has a thick skin that makes it quite difficult to squish it when found. If undetected it will pupate in the remains of the bulb and emerge the following spring. Detection is actually impossible, unless the bulbs happen to be lifted in summer, as all the action is below ground and the first sign is of trouble is the non-emergence of the plant next spring.

The same bulb, almost
completely hollowed out.
Where clumps are large and snowdrops (or daffodils) abundant it does little significant damage, but it is most irritating when it settles on prized a bulb of some rarity. Controlling the problem on a large scale is difficult, though fine gauze netting can be used to protect individual clumps, and perhaps a prophylactic spray of systemic insecticide aplied to the clumps before they die-down would work, if you wish to use such things, but we really just have to live with it and get our revenge when possible.

The adult Large Narcissus Fly, Merodon equestris (Img: Wikicommons)

Thursday 1 September 2011

Dahlia Trials at Wisley

Dahlia 'Oakwood Firelight'
Some of the superb dahlias in the trials on the Portsmouth Field at the RHS Garden Wisley: well worth going to see if you're in the vicinity.

Dahlia 'Honour Francis'

Dahlia 'Hillcrest Jessica J'

Dahlia Tiptoe'
Dahlia 'Karma Choc'
Dahlia 'Josie Gott'

Dahlia 'Happy Single Flame'

Dahlia 'Shadow Play'

Dahlia 'Rockliffe Billy'