Described by the Olympic Development Authority (ODA) as "the largest one-off planting of its kind in the capital", Hillier Nurseries' £1 million-plus contract to supply 2,000 semi-mature trees for the Olympic Games site in east London was a major coup, even for a company with a track record in supplying large-scale projects.
Delivery to the site will begin within the next week or two and continue until late 2011, when all planting is scheduled to be completed.
According to Hillier Nurseries amenity division director Hossein Arshadi: "The process of delivery is complex - for example, in the north and south parks there are three different landscape contractors taking delivery. They will each need to know which tree is for whom and where it goes. There's a lot of work going on behind the scenes to make it all happen."
Four-fifths of the trees will have been grown in Hillier's own 300ha open ground nursery near Liss in Hampshire. The park trees have been containerised in the company's specialist 25ha container nursery near Ampfield, 50km to the west - to which an extra 5ha of land was added for the job.
The largest trees will be some 140 London planes at 60-70cm girth for the more formal public areas of the site. But in the more naturalistic parkland areas, a variety of 2,000 mostly native semi-mature trees will be used, such as ash, lime, hazel and even elm - though there had been hopes earlier that more than 6,000 trees would be planted in the park.
The 100ha park, believed to be the largest created in the UK for over a century, is a key part of the 2012 Games' legacy. Olympics minister Tessa Jowell said at the time of the award: "The trees will ensure the park is a haven for wildlife while giving a sense of the traditional British woodlands."
ODA chairman John Armitt says: "We are not only planting trees that will look fantastic and reflect the traditions of great British parks, but also creating habitats for wildlife and helping to future proof against the impacts of climate change on the park and surrounding communities."
The nursery was also a key player in the Greening the Games cross-industry campaign launched by Horticulture Week that successfully raised awareness among Government, organisers and developers of British horticulture's capacity to enhance the Games.
The campaign brought representatives from the ODA to the Hampshire nursery in order to make clear the long lead times required for successful tree procurement. Arshadi says the nursery saw off continental Europe's biggest and best in order to win the bid.
"We applied through the CompeteFor.com portal, as all suppliers to the Games have had to," he says. "We had to show we had a track record of supplying to other large projects, which we have - for example, the Millennium Dome or the City of Manchester Stadium. However, this will be the biggest single job we have ever taken on."
Indeed, Hillier's record of supplying trees to major national event spaces goes back as far as the Festival of Britain in 1951.
"They narrowed it down to a shortlist of five - as far as I know we were the only British nursery on it," Arshadi explains. "The strength of the euro hasn't done us any harm. But just being cheaper would never have been enough. More importantly, we had to show our ability to deliver.
"They scrutinised all aspects of the company - its size, financial status, management structure - as well as the quality of the stock. The time periods involved are relatively short and there's no room for error or slippage, so they wanted to be sure we were up to the job."
A representative of the ODA bears this out, saying: "Our procurement is designed to ensure that we can deliver high quality, on time and within budget while also meeting a specific set of broader commitments, including health and safety and sustainability. The company performed well across this balanced scorecard and we're confident we selected the best supplier for the job."
Employing a total of 30 staff at the Liss site and a further 12 at Ampfield, the company covers the whole life cycle of the tree from its initial propagation through grafting to containerising when full-size - a process that Hillier Nurseries pioneered and has since become widespread in supplying an industry that values the option of year-round planting.
After being lifted by a purpose-built tree spade (see box), trees are root-balled in hessian and wire, both of which are biodegradable. They are then containerised in Air-Pots of up to 2m in diameter, which encourages the development of fibrous root growth without spiralling. After one season they are ready for shipping to site.
The company has pursued a policy of using only peat-free growing media for seven years. A bespoke formulation of tree bark and green waste is now used in all tree containers. "We first trialled it ten years ago for two seasons and were happy with the quality and uniformity," says Arshadi.
He adds that the recent severe winter has been only a minor inconvenience to the nursery. "The weather hasn't been a problem for us directly, but it has held things up for our customers, who weren't able to put them in the ground," he says. This has also hindered work at the Olympic site, but recent milder weather has allowed the landscape team to get back on track, he adds.
An institution in British horticulture, Hillier will this year be seeking its 65th consecutive Gold Medal at the RHS Chelsea Flower Show in May. The exotically-inspired Adventures in Gardening, presented in conjunction with the Scotts Miracle-Gro Company, will feature tree ferns (Dicksonia antarctica) grown at the nursery, along with new varieties of shrubs and perennials.
The company has aimed to keep an eye on trends in demand and even anticipate them. "There has been a rise in things like pleached trees, parasols and multi-stem trees," says Arshadi. "We even grow trees such as pines trained at an angle to look wind-swept, so they look more natural in a seaside setting."
Arshadi himself has worked for the nursery for 30 years - more than a fifth of its 140-year history. "There are quite a few of us who have been with the company for more than 20 years - it's one of the strengths of the company that we have that kind of continuity," he says.
"We have had to keep one step ahead of the market and that has meant taking some quantified risks. A bedding grower only has to think about what he will grow this season. I have to decide what we will be growing in 10 or 15 years' time."
For Hillier, being able to lift, containerise and ship large semi-mature trees in often tight timescales would not be possible without large purpose-built machinery. The flagship of the fleet is the Optimal, capable of lifting trees with up to a 2m rootball.
"This is as big as you can go with a stand-alone machine," says Hossein Arshadi. "There are bigger units that attach to a lorry, but then you have to get the whole thing to the site."
Even providing access for the Optimal has meant changes at the nursery, he says. "You need a lot of space - the rows have to be at least 8m wide. But once you have the nursery set up, it's very easy to lift trees quickly and efficiently.
"People want bigger trees now for instant impact, but lifting them without technology would take days - it just wouldn't be viable."
The result of a £200,000 investment, the Optimal has already lifted the London planes and other trees for the Olympic site. According to Arshadi: "The people from the ODA wanted to see that we could lift them easily and without any damage."