In the year that we celebrate Lancelot `Capability’ Brown's tercentenary, it is wonderful that we are still able to see one of his landscapes so near to London. Syon was one of Brown's first major commissions, how much of the pleasure grounds and parkland in which those elegant Georgians strolled is still visible today?

The answer is that obviously 250 years of history have swept past. However, Brown laid out two large lakes at Syon, which are the centrepiece of our landscape; the parkland and the foundations of the arboretum that he designed are still here today. Over time there have been a number of changes – some attractive, some less so — but if you look at the bones of the place it is fair to say that it is still very visibly a ‘Brown landscape’.

Much work has been carried out in recent years to reinstate aspects of Brown's landscape. Can you tell us about the practical and financial challenges of such an undertaking?

The opportunity arose to carry out this restoration in conjunction with making other changes on the estate. In the late 1960s various commercial ventures were started, some of which had rather run their course by the late 1990s, and the Duke of Northumberland took steps to put the estate on a better financial footing. As a result a large number of not particularly attractive or profitable buildings went and were replaced by enterprises on a similar footprint, including a hotel, built on a significantly less important area of the site. In turn that allowed us to restore Brown's vision.

In the 1960s, the western end of Brown's Serpentine River had been filled in and about 50 metres had been built over, so it was a major excavation exercise to restore it. In the process we dredged the rest of the water so it's all in better shape now. Elsewhere on the site, buildings were demolished and fence lines moved, which allowed us to restore and extend the Brownian parkland and gardens.

Do any of Brown's original plans for Syon exist, and if not, how do you achieve an accurate restoration?

We have a good archive, including a series of maps and plans. However, Brown worked at Syon for just over 20 years and consequently there were several phases of development, during which time the ‘original’ plans may have changed.

When looking at any historic plan, one of the challenges is to decide whether we are looking at a proposal or a plan of what was finally built. With any restoration the aim is to achieve something that is in keeping and inspired by the original.

We extended the lake in the pleasure grounds back to the eighteenth-century layout, but whether it is exactly where Brown put it, I really couldn't tell you: it is pretty close and with a clear conscience we can say we have restored Brown's lake.

Syon is clearly an important historic landscape. How is a balance achieved between preserving the past and moving the garden forward so it continues to thrive?

Last summer we celebrated Syon's 600th birthday. Henry V laid the foundation stone for Syon's Great Abbey — the only Bridgettine house in England — in 1415. To celebrate, we laid out the lines of the abbey church in the meadow using hay bales. Cardinal Vincent Nichols preached to about 700 local people, and a church service was held in Syon's church for the first time since the reign of Mary I. It was hard work, but great fun to do.

Syon is a very multi- layered landscape, we have everything from pre-history to twenty-first century within about 100 yards of where I am sitting now. We like to say we had the country's first botanical garden: there was a botanical collection here in the 1540s set up by the then owner the Duke of Somerset's physician, Dr William Turner. Turner was a radical Protestant theologian and botanist, which is a great combination. All swept away, but Syon is a very flat site and we have done a lot of archaeology over the years and it is all there a couple of spades down, the abbey, the formal gardens and everything; it may look like a bit of rough pasture but history is immediately beneath our feet.

What I try to do is garden in keeping with the essential spirit of Syon. It's a permanent juggling act between raising the money for restoration and moving forward, but without spoiling in any significant way the historic nature of the landscape. We are not like the Privy Garden at Hampton Court, where the aim is to recreate a garden that looks as much as possible like the famous Knyff painting, c.1703, View of Hampton Court. If I want to plant a tree in our eighteenth-century wilderness I'm not going to be looking through the plant list to find one that was planted here in the 1780s, a nice thing if I could do it, but not something I have to do.

What significant developments took place at Syon post-Brown?

The Great Conservatory is the jewel in the crown: it is the most extraordinary building and was built in the 1820s, which is very, very early for a structure like that. However, the significant story is that in the post-war period, the 1950s and '60s, large estates were an absolute drain on the resources of the private owners and they had to find ways of staying solvent. To that end, in the sixties there was a big garden festival here, which is when things like the Garden Centre appeared along with other commercial developments. It was a very bold venture for its day, but it's not necessarily the way we would go now.

I have read that you have a passion for trees, regarding them as the ‘cornerstones of the landscape’. Can you tell us something about Syon's magnificent tree collection, including its champion trees?

I am very lucky to have inherited a good tree collection from my predecessors. In the nearly 20 years I've been here we've roughly doubled our number of tree species and in another 150 years time that will be paying off. We play to our strengths, developing groups of trees that we already have in order to establish significant collections. This may sound silly in nearly 200 acres, but we are a bit tight on space because the Brown landscape was designed to be ‘open’. So while there might be a couple of acres of available open space, it wouldn't necessarily be appropriate to plant trees there.

The Tree Register of the British Isles designates Champion Trees: they are usually the biggest or one of the biggest of a species. However it can also be the tallest, have the greatest spread or the biggest girth, which doesn't necessarily always mean it's the oldest. We have some fantastic Taxodiums and Pterocarya, there is a massive, spreading Turkish hazel, Corylus colurna, and some superb Liquidambars. We did have the tallest Liquidambar in the country until three years ago and then they found a taller one!

Canaletto's painting of Syon from the Surrey bank of the Thames (1749) shows cattle and horses grazing on the tide meadow. What is its importance to the geography, history and ecology of the Estate?

What I like about Canaletto's painting is that, although it is somewhat foreshortened, if you stand on the other side of the river and look across now, 260 years on, the view is still much the same. There may be a few more trees, but apart from that it is still much the same sort of landscape, you can make out the ha-ha and the grazing animals.

The tide meadow is important as a relict — it would not have been an unusual landscape in years gone by. It has never been built on, developed, embanked or drained, and as a result it is unique. On a good spring tide, it is under water twice a day and it is still grazed by cattle, just as it was in Canaletto's day. If you look at our 1635 Glover map, it is shown there as the Great Meade and part of its ecological significance is its continuity. The challenge in managing it is to stop the wet woodland encroaching. Basically, apart from the grazing, it is hands-off; every five or 10 years we do timber clearance. Accessibility is a real issue — we can cut the undergrowth with a chainsaw, but we couldn't take our tractors down there, they would sink without trace so we use specialist contractors to pick up and remove the timber. Because it is a SSSI we manage it in association with Natural England and to their specification.

In its heyday, the Great Conservatory was full of exotic plants from all corners of the world. It still houses exotics, but today's visitors can also see tomatoes, Swiss chard and other vegetables growing. Do you enjoy breaking down the rigid demarcation of the right plant for the right place?

The conservatory is entirely unheated and the palette of exotic- looking plants that will tolerate a good few degrees of frost is limited. There are only so many hardy palms and cannas that we want to grow so we started growing fruit and veg on one side of the building about seven or eight years ago, and it has worked pretty well. Visitors like seeing them and it means that the space has two different characters. It gets incredibly cold and damp in the winter and is hot and dry in summer. The large cacti do well, they don't seem to mind; we don't water them at all in winter and they go dormant. They prove that plants don't read the books because they all say a minimum of 10 degrees is required, but we often get a good hard frost in there. The lily pond was put in five or six years ago to replace a 1960s rockery. There was a tradition of growing water lilies here, and the Victoria amazonica first flowered here in the 1850s.

Like many other Head Gardeners of large estates, you have had to turn your hand to work on events that have little to do with gardening. How do you feel about generating income for the garden in this way?

I have a fair bit of involvement, although not day to day. There are three strands to our event business: weddings, filming and a few large marquee events, all run by a dedicated events department. Occasionally the gardeners are roped in to assist when film crews are here. We also hold some more specialist events, such as the recent LPGT ‘Capability’ Brown Study Day. The income enables you to do the day job: we recently restored an early-nineteenth-century bridge, the house had a new roof four years ago, and the Robert Adam Lion Gate is on the list for restoration. We have six Grade I listed structures and the maintenance cost comes from income generation. It is a challenge, but it's not insurmountable.

Our biggest visitor attraction is the Enchanted Woodland, and that's very much run by the gardeners. This is our eleventh year now, and Syon was one of the first to illuminate its arboretum. We can get anything up to 15,000 people over nine nights, and the event appeals to a totally different demographic and that's great. Everyone chips in from the cleaners to the managers so it's good fun and marvellous for teambuilding.

What is your own favourite garden or landscape?

An impossible one that, as we live in such a beautiful island; I think the most single beautiful view in the British Isles is looking across Loch Torridon from the south. It is going to sound terribly corny, but an early, sunny autumn day at Syon looking over the water meadows with the cows grazing, the sun slanting through the trees, and the mist coming off the river is absolutely magical, and I can see that from the bottom of my garden so I can't complain too much.

Information about visiting Syon Park can be found at www.syonpark.co.uk