Publications

The Garden
October 2003

The National Arboreta formed

	Clothed in autumn finery, the tree collections at Bedgebury National Pinetum and Westonbirt Arboretum (below) make a colourful display Images: Caroline Edmunds, Bedgebury National Pinetum; Derek Harris, Westonbirt Arboretum

Two of England’s finest tree collections, Westonbirt Arboretum and Bedgebury National Pinetum, are to merge to become the National Arboreta.

Both belong to the Forestry Commission, but until recently have been in different administrative regions. Now the two sites can share facilities.

Simon Toomer, Curator at Westonbirt Arboretum, said, ‘The merger of the two collections will give us the chance to plant trees in whichever collection is more suitable. Each site’s contrasting climate and soil conditions should give the trees a higher chance of survival and help to conserve some more endangered tree species.’

The 240-ha (600-acre) site at Westonbirt Arboretum in Gloucestershire has about 18,000 woody plants including some of the tallest, oldest and rarest trees and shrubs in the UK and NCCPG National Plant Collections of Salix and Japanese cultivars of Acer.

Established in 1925, Bedgebury National Pinetum in Kent extends to 80 ha (197 acres). It has 7,000 specimen trees including 91 vulnerable or critically endangered species, and five National Plant Collections: Taxus, Juniperus, Thuja, Chamaecyparis lawsoniana and x Cupressocyparis leylandii.

For details tel: 01666 880220 (http://www.forestry.gov.uk/) for Westonbirt or 01580 211781 (http://www.bedgeburypinetum.org.uk/) for Bedgebury.

Alien threatens national flower

	Hyacinthoides non-scripta (English bluebell) has fragrant flowers borne on one side of the stem. The anthers are cream-coloured and unequal and the raceme is nodding Image: Peter Wakely/English Nature
	H. hispanica (Spanish bluebell) has unscented flowers borne on all sides of the stem. It has blue, equal anthers and an erect raceme Image: Mike Grant

English bluebells (Hyacinthoides non-scripta), proposed as the country’s national flower in a recent Plantlife survey, could be at risk from hybridisation with an alien species. The Spanish bluebell (H. hispanica) is widely grown in British gardens because it is more decorative than its English cousin.

However, it is hybridising with the native species and producing hybrid offspring. These hybrids (H. x massartiana) are fertile and backcrossing with both species. As the less-vigorous native bluebell cannot compete successfully, its long-term survival is under threat.

Hybrid bluebells are becoming widespread in the countryside - the result of pollination by bees and the dumping of unwanted bulbs beside the road.

In addition, the Society is concerned that many bulbs on sale in Britain as native bluebells, are in fact hybrids with the Spanish bluebell, and that wording on the packaging that accompanies the bulbs can be misleading.

The Society is advising gardeners not to plant cultivated bluebells in the countryside, and to consider the effect of planting Spanish or hybrid bluebells in gardens where populations of wild English bluebells exist close by. When buying bluebells, make sure they are described as Hyacinthoides non-scripta (or are listed under their former names of Scilla non-scripta or Endymion non-scriptus).

Simon Thornton Wood, Head of RHS Science, Advice and Libraries, said, ‘The RHS continues to urge bulb growers to ensure plants sold as Hyacinthoides non-scripta are correctly named. Customers are too often confused by poor or incorrect labelling. Furthermore, like our other valued native plants, bluebells should not be harvested from the wild.’

The UK has about 30 percent of the world’s population of bluebells, which thrive in our moist Atlantic climate. However, the species has declined over the past 50 years because of woodland clearance, the conversion of deciduous woodland into coniferous plantation and the decline in the practice of woodland coppicing. The bluebell has also suffered from over-collection in the past, but it is now illegal to collect seed or bulbs from the wild for commercial purposes.

Further information from English Nature on 01733 455100.

Giant hit by Russians

A biological control for Heracleum mantegazzianum (giant hogweed) may have been found by scientists at CABI Bioscience in Egham, Surrey.

Marion Seier and her colleagues have identified three fungal pathogens from Russia - the plant’s place of origin - including Septoria heracleicola, Phloeospora heraclei and a new species of Ramulariopsis.

‘Results from the past two years’ research show that the fungi can reduce hogweed’s vigorous growth and, if released in the UK, could decrease the number of plants to levels seen in its native habitat. This strategy has been successful in other countries, but has not yet been tried against weeds in Europe.’

She explained that none of the three species has been recorded
on giant hogweed before and the genus Ramulariopsis has never been reported on any plant in the same family as giant hogweed.

‘The results are encouraging because, at the start of this project, virtually no records existed documenting the presence of natural fungal enemies of this plant in its native surroundings. However, a great deal more work needs to be done before we can be certain that these fungi are specific to giant hogweed,’ said Marion.

For further information visit the website: www.flec.kvl.dk/giant-alien

Search for the pink ballerina

This autumn, gardeners are asked to look out for pink waxcaps (Hygrocybe caltyptriformis) on lawns, woodland edges and grassy meadows. Image: Lorne Gill/SNH

This distinctive white-stemmed fungus with a pointed pink cap is listed in the UK Biodiversity Plan and is part of plant conservation charity Plantlife’s Back From The Brink programme.

Plantlife is also asking people to look for yellow-green parrot waxcaps (H. psittacina) and blackening waxcap (H. conica), which turns from red to black when it is damaged. The survey closes on 31 December 2003.

For more information visit www.plantlife.org.uk or tel: 01722 342730.

More jobs lost

Horticulture Research International (HRI) has announced that about
100 members of staff are to be made redundant at its Wellesbourne, Kirton and Efford sites.

These redundancies have been implemented after the Government accepted the findings of the Quinquennial Review. A decision about HRI’s sites at East Malling and Wye is expected shortly.

Scorched apples and vintage wine

High temperatures and a shortage of rainfall in August are having an effect on the British fruit-growing industry. Soft-fruit harvests were curtailed and apples are now suffering from scorch, but wine growers are quietly confident about a quality vintage after weeks of hot weather which included, on 10 August, a record UK temperature of 38.1°C (100.6°F) at Gravesend in Kent, and a local high of 37.8°C (100°F) at RHS Garden Wisley.

According to Jim Arbury, Superintendent of the Fruit Department, ‘It was so hot at Wisley that some early apples started to cook on the fruit trees before becoming ripe, and ‘Bramley’s Seedling’, ‘Pixie’ and other cultivars suffered from sun scald. Perpetual strawberries may go into high temperature dormancy and raspberries had finished before the end of August.’ Soft fruit growers throughout Europe also lost a large proportion of their crop.

Ted Hoday, Chief Guide at the Brogdale Horticultural Trust, Kent, said that apples there have also suffered from sun scald. ‘Plums on the outside of trees always ripen before those on the inside, but this year the difference was more marked, particularly those on St Julien rootstock.’

In the South of England the apple harvest started between seven and 10 days earlier than usual, but temperatures were less extreme in the north of England. Hilary Dodson, Chairman of the Northern Fruit Group, has found: ‘Everything is ahead of time and the fruit is smaller, but apart from that we have had no problems.’

British vineyards are hoping for their best vintage for several years, although low rainfall could reduce yield. As this issue of The Garden went to press, Carl Koenen of English wine producer New Wave Wines of Tenterden was ‘quietly happy’ with how things were going. ‘The harvest appears to be early and there is likely to be a good balance of acidity and sugar.’

RHS archives help Dyffryn

Restoration work continues at Dyffryn Gardens, in the Vale of Glamorgan, to reinstate the designs of Thomas Mawson.
The original plans of the garden rooms have been lost, but paintings by Edith Adie (see Priceless record of The Dyffryn, p762) and many photographs of the planting in its heyday have provided a great deal of information on colour combinations, plants, hedge heights and the positions of statues.

Assisted by the Heritage Lottery Fund, work began in 1997 on the now completed Pompeian garden (above) and attention is now turning to the walled garden and display glasshouses.

Dyffryn gardens are open to the public during the restoration process. Tel: 029 2059 3328 or visit the website www.dyffryngardens.org.uk

Protecting Seychelles’ endemics

British horticulturalists are helping people of the Seychelles archipelago to save Lodoicea maldavica (coco-de-mer palm) and other endemics.

Scientists from the Eden Project in Cornwall have enabled the islanders to propagate 60 rare endemic plants, which may be returned to the wild in the future.

Alistair Griffiths, Acting Head of Technical Support at the Eden Project, said, ‘The jellyfish tree (Medusagyne oppositifolia) is one of the rarest plants in the world, with only 50 specimens left in the wild. We have propagated it at Eden and now have 40 seedlings.’

This work is supported by the Government-sponsored Darwin Project, which has developed a strategy for conserving critically endangered Impatiens gordonnii 2 with help from the Seychelles Forestry Department. Image: Alistair Griffiths

As part of the project, two people from the islands have learned propagating techniques from British nurseries such as Hilliers in Hampshire.

Situated in the Indian Ocean, the Seychelles are home to 72 endemic plant species. About 130,000 tourists visit each year, which is having an impact on the islands’ delicate ecosystem.

As large areas of lowland forest have been cleared, and cinnamon and vanilla plantations occupy most of the coastal plateau, many endemic plants are now restricted to one or two locations and these often have limited genetic diversity. The cloud forests, rich in ferns and mosses, are threatened by invasive alien cinnamon and guava plants.

Chilean monkey-puzzle trees devastated by fire

A forest fire has destroyed 71 percent of the remaining Araucaria araucana (monkey-puzzle) trees in the Malleco National Reserve in Chile. This was a location for the television series Walking with Dinosaurs, and trees thought to be at least 2,000 years old have been lost. Araucaria araucana has been declared a protected species in Chile, and just 250,000ha (600,000 acres) of monkey-puzzle forest now remain, restricted to only a few small areas of the Andes and on the coastal mountains.

The Department for Environment, Food and Rural Affairs (DEFRA) is funding a project to help local people set up a nursery. However, the trees can take more than a century to mature and produce seed.

Further information is available in the DEFRA-sponsored Towards a Global Tree Conservation Atlas, which shows that 8,000 species of tree are facing extinction in the wild. It is available as a pdf from www.unep-wcmc.org

Solving a stony problem

English Nature is concerned that over-collection of pebbles for mulching and landscaping purposes is causing damage to some of Britain’s beaches.

Considerable amounts of shingle have been taken from the beach at Crackington Haven in Cornwall, and St Genny’s Parish Council has printed a leaflet, asking visitors to refrain from the practice.

While shingle beaches may look substantial, they often form an integral part of the coastal flood protection scheme and their removal could be disastrous.
Gardeners wishing to use shingle as a decorative mulch should ensure that it has been obtained from a quarry. An English Nature biodiversity action plan for vegetated shingle is on the website www.english-nature.co.uk/baps/habitats.

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