Function over fashion

Sustainability means that native trees are increasingly coming into fashion, says Jez Abbott.

Yellow could be the new black, reckons Mike Vickers. The sales director of JA Jones is looking at what's hot in trees and what's not. The yellow-leaf Acer 'Princeton Gold' is definitely moving the mercury in the right direction.

He and his colleagues at the Southport nursery are reviewing trends across Britain. In their line of work these mean more than hitching a lift on the latest whimsical bandwagon. On the nursery it can take years to develop and nurture that elusive winner.

The golden-coloured spring leaves of A. 'Princeton Gold', which turn a warm yellowy-green shade in summer, could be the dream ticket. It will, Vickers hopes, bring colour and brightness to parks, streets, lawns and sundry other landscapes in enough profusion to register their must-have status.

This "newish variety", like so many others launched unto an unsuspecting world, represents a gamble in time and effort. First there is the commitment, in this case to grow only 100 or so trees to test the market. But because few people know about the tree, pushing sales is tough.

All the while, time is passing by, so when the tree finally segues across the threshold from obscurity to wider-spread recognition and demand starts to rise, you may have reigned back on planting. Net result? You may have missed the all-important chance of hitting pay dirt.

You must be resolute, says Vickers, whose team is no less: "By the time a new tree becomes significant and people want to specify it for a few years' time the production cycle may have finished. This is one of the difficulties with new trees, so you have to decide to stick with a plant."

Vickers' team stuck with A. 'Princeton Gold', which meant a two- to three-year slow burn of sluggish sales before the orders started to roll in. JA Jones supplies contractors working on jobs designed by landscape architects, which right now are specifying more than A. 'Princeton Gold'.

Other trees of trend this year include Carpinus betulus 'Fastigiata' Award of Garden Merit (AGM) and C. betulus 'Frans Fontaine'. Multi-stemmed Amelanchier canadensis, meanwhile, is a good example of how hard it can be to hit the right supply-and-demand tempo, so crucial to success for the likes of 'Princeton Gold'.

"These are proving scarce yet more popular. The trees are not there. Production can move in five-year cycles but if a plant suddenly becomes popular you can sell out of last year's, this year's and next year's stock in one season. As the years go on, stocks run scarcer," says Vickers.

Some nurseries have been caught out by the mismatching of supply and demand. Growers, forecasting trends, will plant 400 of a type of tree instead of 200 - only to have to burn them when the season turns out sluggish after all. Next year they grow 50 of the trees, which are now a rarity.

"These things go in cycles. Prunus: every nursery in Europe has it and you can buy the trees for next to nothing. Tilia cordata 'Greenspire' AGM, meanwhile, is fairly scarce due to the fact that four years ago there were thousands but the demand did not go up. Supply, therefore, went down."

Trends in trees, like trends in everything from trinkets to trousers, are a fine balancing act between supply and demand. There is another factor: the designer. This person, reckons Vickers, often has a limited palette. Choosing shrubs more often than not is defined by a desire for "nice, soft ground cover" rather than the urge to push boundaries.

Down goes the Cotoneaster which, fortunately, is grown in tens of thousands year upon year, making it a safe and stable choice for landscape architects in need of large quantities of plants. Even if designers wanted to try out a new plant, it is unlikely it would be available, says Vickers.

The other factor driving trends is money, which never goes out of fashion but frequently runs short on supply. Right now, specifiers want straight trees with upright heads that require minimal upkeep and don't interfere with traffic sight-lines.

The exchange rate is also helping, so while the strengthening euro is forcing competitors on the Continent to push up prices, UK nurseries are becoming better value by the day.

Then there is the slump in the housing market. A year and a half ago, JA Jones was riding high on demand for specimen shrubs. Sales of 10-litre hedging to housebuilders peaked at around 60,000 last December. Now they are down to 15,000. Everybody, says Vickers, is seeing a big drop in demand for the larger plants in an effort to keep down costs.

Steve McCurdy is watching two trucks being filled with large - very large - birch trees from his nursery, Majestic Trees, for the country retreat of a well-known modern artist. Praise be to the modern artists of this world for bucking a trend: large trees are not shifting as fast as in previous years.

"Some customers have gone for smaller trees," says McCurdy, based in St Albans, Hertfordshire. "It's a price thing." So while Majestic Trees has enjoyed its best-ever sales in terms of numbers, the value of the sales is a little down "because people are more cautious with their money".

That said, a generous marketing push can do wonders. Styrax japonica received a helping hand from McCurdy's marketing budget and is selling well. Marketing is important and so is publicity, he says. While some designers have to settle for the same-old-same-old, others are defining trends.

"There is no question; if somebody does a fantastic garden at Chelsea which throws emphasis on a certain type of tree, that tree gets headlines and becomes the next must-have. This drives trends and therefore sales. It's like fashion, cars or anything.

"Sometimes people are motivated by the price of petrol, at other times when money is free and easy they go full tilt for luxury. Right now on the nursery we are going through the fixation-on-petrol phase. It's more down to cost."

But even on the nursery, a few stalwarts continue to shine through even the bleakest clouds of economic downturn. McCurdy sells more birch than he can grow, meanwhile evergreens like Thuja go down a treat for customers who seem to never tire of screening off their neighbours.

On the other hand, McCurdy is not alone in seeing declining popularity in horse chestnut. Boningale Nurseries in Wolverhampton is to supply hundreds of trees for a Park & Ride scheme in Taunton, Somerset (see case study, p31). Native planting will feature strongly in what is anything but a limited plant palette.

The nursery, which won the job in August, will work with UPM Tilhill on a design including 1,300 oak, 800 smaller birch, beech and Prunus trees, 100 Betula utilis var. jacquemontii, field maple, ash and hornbeam. There will also be blackthorn and hawthorn.

But no horse chestnut, says Boningale sales and technical support manager Fleur Smith. Recent scares over canker and other pests and diseases seem to have put off many specifiers, says Smith, who regularly gives presentations to landscape architects on the importance of native planting.

This, she feels - along with her colleague, sales director Frank Sandford - reflects in part growing pressure on designers and specifiers from planners to fulfil environmental obligations. Native trees are, of course, great for native wildlife. Sandford is not alone in singling out BREEAM. This environmental-assessment certification scheme was pioneered by the Building Research Establishment to enable developers to minimise environmental impact of buildings and surrounding landscapes (see box, p26).

Managing director Andrew Holksworth of Tendercare Nurseries in Uxbridge, Middlesex, says: "Planners, as much as designers, seem to be defining trends and are pushing for more native trees through BREEAM. This is meant to encourage landscape architects to use more native species."

He is not convinced: "It needs more development: as it stands it is a bit too academic and is not really related to what will grow well and what's available in the nursery industry. Nevertheless, we have seen instances where schemes granted outline permission have been told at detailed- application stage that the scheme needs more native trees."

Managing director Mike Glover of Barcham Trees in Ely, Cambridgeshire, sees multi-stemmed trees going into places where a year or two ago a standard would have been the preferred option. Amelanchier, Betula utilis var. jacquemontii, Eucalyptus and hazel are all selling well.

Multi-stem trees, he says, are especially good on exposed sites, where their structure and low centre of gravity often prove more robust than a stem and a crown. Trendy trees are not always the right trees.

Rowan, for example, which evolved on wet grasslands, will struggle in a hot, dry tree pit in Birmingham with sun reflecting off the pavements. Glover insists trends should be less about form and colour and more about form, function and physiology.

Glover has just published a book, It's Time for Trees, on the subject of choosing the right specimen for the right place. Making that choice can be a tough call, as it was when architects for the National War Memorial asked for an evergreen that would retain a tight, columnar shape over time.

The client wanted a tree that could be planted on an exposed, man-made mound and Barcham Trees had to balance the finest aesthetics with the doughtiest common-sense practicality.

Glover says: "When trees go wrong it's not so much their fault, it's where you put them. Trends in trees must be dictated to by the physiology of the tree and its end position. No matter how popular Betula utilis var. jacquemontii is, for example, if you plant it exposed and by the coast it will have a tough time. Trends must be led by the needs of the tree, not on how good they will look.

"After discussions on soil types, pH, maintenance and lead times we suggested Quercus ilex AGM pillars for the memorial site. These could be easily maintained to retain the specification while thriving in that location. The plants were sourced and selected in Italy, transported to Barcham for containerisation and acclimatisation for two years before final planting."

The memorial, the first architectural tribute to armed services' victims of terrorist attacks since World War Two, was opened in 2007 and includes almost 60 4m-tall holm oaks in 500-litre containers planted in Alrewas, Staffordshire. Each tree cost £2,500 from a landscaping budget of £200,000, and earlier this year the project won a National Monument Special Award.

Jim Hillier, a manager at Hillier Nurseries, has also noticed big demand for native varieties. Ulmus 'New Horizon' - not an old English elm but a tough, disease-resistant hybrid - continues to sell well. Around 100 were planted four years ago in Pontcanna Park, Cardiff, and the success rate to date has been 100 per cent, he says.

Meanwhile, the Olympic Park in London is being hyped as the biggest ever one-off tree-planting contract in the capital and will brim with natives and English-grown trees (see box, above). And a new hospital project in Bristol will include landscape dotted with 50cm-girth oak trees. Natives, he says, are the "in thing", mainly due to sustainability.

"Lots of councils and planners are stipulating native trees and shrubs," says Hillier. "Meanwhile, the climate change debate is prompting more calls for canopy cover. So while economic downturns can force people to buy smaller trees, demand for larger ones is still high."

Hillier is also selling trees with narrower crowns for street planting, while "designer" plants like topiary trees and instant hedging are popular with landscape architects. Trends in trees may not be as ephemeral as those for trinkets and trousers, but they are far from hard-and-fast. And like the finest trendsetter, says Hillier, you have to cut your cloth to fit.

BREEAM

BREEAM, the Environmental Assessment Method and certification scheme pioneered by the Building Research Establishment (BRE), not only helps developers minimise the environmental impact of their buildings but has helped forge trends in trees and bushes. It works by assessing the performance of buildings in nine key areas, including ecology.

Senior ecology consultant John Polley of Middlemarch Consultancy near Coventry, which assesses sites, says: "The growing emphasis on the ecological arena - not just BREEAM - has had a major impact on tree trends among site developers and designers in recent years."

Polley visits sites to draw up an ecological survey and map out important trees, hedgerows and habitats. If existing wildlife areas cannot be retained or the project is lacking environmental elements such as meadowlands and woods, Polley's team will pull together a list of native, local trees.

This is having an effect on trends in current schemes. If designers fulfil certain criteria such as planting X amount of trees or so many metres of hedgerows that are species-rich they get credits. The more credits they get, the higher the rating.

Credits are given in each of the nine areas according to performance, then a set of environmental weightings enables the credits to be added together to produce a single, overall score. From this, projects are rated on a four-point scale, from pass to good, very good and excellent.

The BREEAM certificate that is awarded can be used for promotional and environmental purposes and it has become good practice to include an ecological assessment for even the smallest urban site, says Polley.

"This is because ecological credits do not depend on the site having lots of wildlife to start with: it's more about how you are protecting and enhancing whatever is there. So even for a rebuilding project on derelict land, ecology is a key part of the BREEAM process. This encompasses many projects and will inevitably have some impact on trends and choices."

The nine BREEAM areas of assessment are:

- Management: overall management policy and site leadership

- Ecology: ecological value and conservation of the site

- Energy use: energy and carbon dioxide (CO2) issues

- Health and well-being: indoor and external issues affecting well-being

- Pollution: air and water pollution

- Transport: transport-related pollution- and location-related factors

- Land use: greenfield and brownfield sites

- Materials: environmental implications of building materials

- Water: consumption and water efficiency

TOP TREES

Carpinus betulus - 'Fastigiata' Award of Garden Merit (AGM) This upright hornbeam is a medium-sized tree with a pyramidal form. Lithe and slender when young, the tree is often grown in tight, restricted areas but is better grown in more open land such as parks as it can put on a fair amount of mid-life spread. 'Fastigiata' offers gold and orange autumn colour and grows well on most soils, including clay and chalk. It can also tolerate poor planting conditions. According to Barcham Trees, specifiers should look for a "straight trunk tapering to a well-defined leader". Its height when mature is up to 20m.

Amelanchier canadensis - This compact, multi-stemmed tree is a popular choice for small spaces and can tolerate cold and wet and urban pollution. It offers a mass of white blossom in spring, while autumn is heralded by leaves that turn a brilliant red-bronze colour. The tree can grow well on all neutral to acidic soils but can struggle on poor or chalky soils. It can also put up with full sun. Amelanchier is often used for fast-growing screening, as a container plant or a small specimen tree. It is also often used to form the backdrop of a border.

Betula utilis var. jacquemontii - The Himalayan birch's trademark white, peeling bark is accentuated by dark scoring. The native of the western Himalayas is a large, slender tree with ascending branches and is good for growing as a multi-stem. Its oval green leaves turn golden-yellow in autumn and the birch shoots yellowy brown catkins in spring. The tree is often a first choice for urban plantings and is used as a feature tree or as part of a group. It tolerates most soils and can rise to a height of 15m to 20m when mature.

Tilia cordata 'Greenspire' AGM - The small-leaved lime is a good choice for urban landscape designs and is often used for uniform planting for streets and avenues. It is also tolerant of air pollution and its medium size makes the lime a popular option for tight sites. Its height is perhaps one of its biggest boons, as is its exceptional tolerance to difficult conditions.

OLYMPIC PARK

The London Olympics is just under three years away, but a seminal starting gun goes bang in couple of months. The first of the trees for the site are to be taken from their container nursery in Hampshire and dug into the north and south areas of the Olympic Park.

Jim Hillier, account manager for local authorities at Hillier Nurseries, says the project is the biggest-ever one-off tree-planting contract in the capital and the first for a park for 100 years.

That project includes around 2,000 semi-mature British-grown trees, which were hand-picked by the organisers for the London 2012 Olympic Park. The trees will form the heart of the 10ha park, but fears of processionary moth have ruled out the quintessentially British oak tree. Instead, alder, birch and Sorbus will give height and gravitas to the nascent landscape. Largest by far will be London plane trees, with 70cm girths, which are due to be planted on the site not this year but next winter. Choice of native trees reflects a trend that is likely to endure, says Hillier.

The 4m- to 7m-high plants have been grown by Hillier Nurseries, which has worked on other culturally defining projects including the 1951 Festival of Britain, the Manchester Commonwealth Games Stadium and the Millennium Dome.

"The trees were chosen to future-proof against climate change and are predominantly native species such as ash, alder, willow, birch, hazel, cherry, poplar, London plane and lime," says John Armitt, chairman of the Olympic Delivery Authority.

"Trees will provide shelter from wind and sunshine across the park; willow and alder will be planted in river areas to withstand flooding and species vulnerable to climate change have been avoided."

RHS superintendent for woody ornamentals Colin Crosbie says the planting will equate to a city wood. And Armitt says the best qualities of native trees chime with so many buzzwords of 21st-century urban living.

"We are cleaning up former industrial land to create the largest urban park in the UK for over a century. It will form a cornerstone for the regeneration of the area. We are planting trees that will not only look fantastic and reflect the traditions of great British parks but also create habitats for wildlife and help fight against the impacts of climate change on the park and surrounding communities."


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