Carolyne Locher takes a stroll through the National Trust’s only dedicated arboretum, accompanied by head gardener Graham Alderton.

IT is mid-morning within a week or two of ‘peak bluebells’ at Winkworth Arboretum in the Surrey Hills Area of Outstanding Natural Beauty. The Arbor Café’s outdoor socially distanced picnic table seating is full and at the entrance kiosk, visitors dressed for all weathers await their timed entry into the 120-acre grounds.

Graham Alderton, head gardener for the National Trust’s Surrey Landscapes Portfolio, is in the works yard outside the arboretum’s offices. When asked which of the three walks best accommodates the spring highlights, he offers: “Shall we walk together?”

The National Trust was founded in 1895, to promote the permanent preservation for the benefit of the nation of lands and tenements (including buildings) of beauty or historic interest. One of the UK’s largest conservation charities, it is supported by 5.6 million members and manages 248,000 hectares of land and upwards of 500 historic houses, castles, archaeological and industrial monuments, gardens, parks and nature reserves.

Forestry Journal: Spring Walk.Spring Walk.

Winkworth Arboretum is the only dedicated arboretum in the National Trust. It was gifted to the National Trust by leading dermatologist, amateur arborist and practical tree planter Dr Wilfrid Fox in 1952. Independently wealthy, Dr Fox purchased farmland, a steep wooded valley and lakes, in tranches between the two world wars. Inspired by arboreta such as Westonbirt and advised by luminaries such as W J Bean (curator of Kew Gardens), he began using plants ‘to paint a picture’ across the steep slopes and bowls in 1937. Today, the arboretum contains over 1,000 species of shrubs and trees.

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In a normal year, Winkworth receives 160,000 visitors. Even with staggered public admittance and members making the effort to visit during the week, the upper arboretum is popular. A steady stream of walkers head eastwards, passing the substantial ground-strewn stems of the natural play area (created on an ex-compartment of larch flattened by the 1987 storms) towards Spring Walk and Bluebell Wood. Graham says later: “It is always busier at the top. The further away you are from the tearoom, the fewer visitors you see.”

Forestry Journal: Graham Alderton standing next to the trunk of his favourite tree, a dawn redwood (Metasequoia glyptostroboides), which could well be an original Fox planting.Graham Alderton standing next to the trunk of his favourite tree, a dawn redwood (Metasequoia glyptostroboides), which could well be an original Fox planting.

Meandering along Spring Walk, the overcast light fails to dampen the vibrancy of burnt-red acer leaves, the blooms of pink camellia and burgundy rhododendrons managed as trees and the pink buds on magnolia trees that have survived the late frosts. These slopes were once covered by Douglas fir and larch, felled first by the war department and again in the 1980s when it was sold for timber. The honey-coloured stems of adolescent Stewartia (P2008) planted above Badgers’ Bowl are also worth a mention, given that this slope has recently been cleared of dense self-set bracken, bramble and hazel pioneers.

The lilac ground cover evident on Spring Walk’s slopes intensifies to purple in Bluebell Wood, an oak-studded ancient semi-natural woodland whose bluebells are “just starting to take off. Young oaks have been planted in the gaps for continuous canopy cover and where thinning has taken place, the brash is built up for habitat”.

Forestry Journal: Stewartia stems.Stewartia stems.

Up-slope in woodland beyond the scope of our ramble, the gardens team has just completed three years’ worth of bringing an old sweet chestnut coppice back into rotation. “This year they felled a complete copse. We use the timber for steps and any posts and rails we require. At some point, I hope to encourage some of our weekday volunteers that are interested in woodwork to make items to sell.”

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Horticulture (and arboriculture) is Graham’s second career, which he came to after a series of injuries ended his career in the police in 2000. Working in a nursery, he built a contract-gardening round before moving to Wiltshire to work on a garden restoration for three years. Embarking on horticultural qualifications, a National Certificate in Horticulture (Merrist Wood) and traineeship at Oxford University Botanic Garden were followed up with a three-year diploma at Kew (including a year in the arboretum). Graduating in 2010, he spent six years as a head gardener in Kent before joining the National Trust in 2017.

He is supported by a team of six gardeners across two Surrey properties, Arbnet Level 2-listed Winkworth and Grade 1-listed Claremont English Landscape Garden (Esher).

Forestry Journal: Site map.Site map.

That Graham, 53, loves plants and trees and his role is putting it mildly. In contrast to the naturalistic style of management favoured by his predecessors, he prefers the more spacious approach found in English landscape gardens. “Many of these trees are quite exotic and need the space to grow. Visitors to an arboretum want to see the species, the beauty and profile and they need space to be able to see and recognise them. We have good collections of acer, azalea, birch, camellia, oak, holly and magnolia set in a design landscape. It is a landscape arboretum, here purely for beauty.”

Dodging Phillimore Wetlands, we cut down through Bluebell Wood to Badgers’ Bowl. Burgundy acer leaves rustle above a statement bench – straight-backed seats hewn in a fallen trunk at the bottom of the wood. “Dr Fox planted Japanese acers in this ancient wood, acknowledging early on that this was not something you would normally do in a traditional ancient woodland. However, they look fantastic, glowing red in autumn and with the leaves on the ground, it is just ... beech.”

Graham’s flow is broken by a visitor enquiry – he would not have it any other way – and he responds warmly to all questions that come his way.

Forestry Journal: Azalea Steps. In WW2, Canadian soldiers billeted at Dunsfold used Rowe’s Flashe Lake for training before D-Day. They helped build these steps.Azalea Steps. In WW2, Canadian soldiers billeted at Dunsfold used Rowe’s Flashe Lake for training before D-Day. They helped build these steps.

A quick detour into the wetlands (a drained lake) is via a wooden walkway and a sign warning ‘Danger, deep mud’. The stream, currently free-flowing, dries up during prolonged periods of dry weather. With staff (and volunteer) furloughs, unmanaged vegetation is encroaching. “We will have to dig out some tussocky grass and remove some alders. If not, it becomes an alder carr. In our 10-year plan, we want to revitalise this area by increasing the number of footpaths and building a bird hide.”

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To encourage the feel of a ‘landscape arboretum’, a restoration plan was devised. “Phase 1: Clear the site. Phase 2: Take stock. Phases 1 and 2 ran concurrently. Phase 3: Consult the Conservation Plan, succession plant and make sure it all makes sense. Phase 3 begins this year, budgets permitting. We know what we want. It is a case of sourcing it, bringing it in and planting.”

Dr Fox did not keep planting records and the gardens department has gone through three changes of database. After they mow, cut and prune, the gardens team curates Winkworth’s arboricultural assets, identifying 6,000 trees so far. “I have just finished the oaks (26 species) and the champion trees (70). One senior gardener has completed the camellia and another spent winter locating, labelling and plotting acers into the database.”

Forestry Journal: Graham shares an image of the Bowl’s dense tree cover before the two-year restoration thinning.Graham shares an image of the Bowl’s dense tree cover before the two-year restoration thinning.

All team members are trained to undertake tree surveys. They spend three months of the year surveying the high-risk areas. Remedial works must be completed within three months or less. Following the restoration clearances, arboricultural management follows a policy of non-intervention where possible, “unless a tree is dangerous. We have team members with chainsaw tickets for large fells but rely on contractors to climb for us. Anything we take down, we chip and use on pathways or as mulch once it has been around for a year.”

Nearing a monkey puzzle at the bottom of Badgers’ Bowl, we look back to the sugar maple (Acer saccharum) that is Winkworth’s indicator tree, being the first to turn red in autumn. Of the monkey puzzle Graham says: “When I got here, the lower branches were hitting the ground and very untidy. We raised the crown – helpful when it comes time to mow – and now it looks much better.”

Where the Azalea Steps meet the Bowl’s lakeside path, the boathouse and dam, the exposed roots of an ex-plantation Douglas fir cling valiantly to the sandy slope. Tempting as it is for children to climb on, “to save the roots from further damage, we will move more soil here, plant some hydrangeas and rope the area off.”

Forestry Journal: Acer palmatum ‘Bloodgood’. Burgundy acer leaves rustle above a statement bench – straight-backed seats hewn in a fallen trunk at the bottom of the wood.Acer palmatum ‘Bloodgood’. Burgundy acer leaves rustle above a statement bench – straight-backed seats hewn in a fallen trunk at the bottom of the wood.

A dawn redwood (Metasequoia glyptostroboides) growing opposite could well be an original Fox planting. “You asked my favourite tree. This is it. The name rolls off the tongue and it has a lovely shape!” That this species was only discovered in China during the 1940s does not make this redwood the rarest tree in Winkworth’s collection. That title is reserved for the lime-leaved maple (Acer distylum), “a nice little tree that sits innocuously near the entrance”.

At the bottom of the site, Rowe’s Flashe Meadow is relatively unpopulated, and the eastern belt of trees hides a forest school. This meadow is the place to be in autumn to witness the Bowl’s fiery red hillside reflected in Rowe’s Flashe Lake. Above the lakeside larch and Atlantic cedar, Dr Fox planted up the hillside with Quercus coccinea, Quercus rubra, Liquidambar and Acer rubrum. In 2017, artists were given four and a half hours to capture this view during the televised finals of Landscape Artist of the Year. “The acers turn dark red and when the leaves drop, you get a red base and red top. It’s fantastic.”

Graham shares an image of the hillside before its two-year restoration (thinning). “People did ask why we were removing trees. We explained that Winkworth is not woodland, more a garden with trees that deserve to reach their full potential, and to open up the view. Now people sit and eat picnics among them. That is important, people getting close to the trees.”

Forestry Journal: At the top of the slope above Oak Bank, Fox-planted (now gnarled) Acer rubrum (very left) and in front of the bench and viewpoint.At the top of the slope above Oak Bank, Fox-planted (now gnarled) Acer rubrum (very left) and in front of the bench and viewpoint.

Local visitors were welcomed throughout all pandemic lockdowns and two senior gardeners remained on site. Fewer visitors gave the grounds time to recover. With fewer meetings, Graham had time to repair the paths and he began gardening again.

At the end of the lakeside trail, Japanese acers have been felled to stumps, with one left for honey fungus to ‘attack’. “By doing this, it seems not to spread a great deal.”

READ MORE: Forest Canopy Foundation: Increasing woodland creation

Skirting Sorbus Hill, Oak Bank’s interlocking azalea have been thinned. Some Liquidambar struggle with water shortages on the sandy lime-free slopes and tree gauges and water bags are being trialled.

At the top of the slope, Fox-planted (now gnarled) Acer rubrum surround a bench and viewpoint. “I want to plant more to ensure succession and colour for the next 100 years. It’s a case of where. We can’t plant in front of the bench because that is a nice viewpoint, and we can’t plant too close to other trees in case they are affected.”

Forestry Journal: A beech coppice that has spread.A beech coppice that has spread.

Along the length of Champion Alley, the benches are full of visitors soaking up the views. Passing a Surrey Champion Dombey’s Southern beech (Nothofagus) and successor, Graham shares one of his favourite views: a grove of papery birch (Betula) stems glowing white against deeply purple bluebells. One birch has been monolithed. “Children love them. We have left a laurel for them to bounce on.”

Ex-situ conservation is something Graham wants to do more of. “We have Magnolia Wood, Holly Wood and Sorbus Hill where we add to the collection, but it is nice to have the odd specimen that is a bit different.”

Returning to the Winter Garden via the tall wooden ship-like structure of a second natural play area (built three years ago to allow school-aged children to get nearer to tree crowns) and the Dr Fox Memorial, a pioneer European hop-hornbeam (Ostrya carpinifolia) divides opinion on its beauty. “It had two trees fall into it. It is a survivor.”

Forestry Journal: Every garden (or arboretum) starts with the evergreens.Every garden (or arboretum) starts with the evergreens.

Close to the entrance, the Winter Garden is a favoured spot with visitors for eating picnics. It will receive an upgrade (new path and new plantings for texture) if budgets allow and plans for a new visitor reception, indoor and outdoor retail centre, café, car park and offices get the go-ahead following the pandemic hiatus.

When asked by the general manager what the gardens department needed to realise their ambitions, Graham responded with ‘two dedicated arborists so that all management can be done in-house’ among other things, including equipment upgrades.

A recent equipment demonstration by Stihl impressed Graham, particularly the attention given to the compatibility of battery technology, retroactively and for the future. “If we could fund small-scale solar, then we would be completely off-grid,” which would be an environmental gain.

Winkworth has limited scope to add new tree cover in line with National Trust ambitions of planting 20 million new trees by 2030. Of planting for a changing climate, Graham says: “There is still disagreement as to what climate we will be getting. It is not as simple as planting what they have two degrees south in France. We will still have extreme weather conditions. Some of the best planting is done instinctively by trial and error.”

In the garden department’s yard, a delivery from the National Trust Plant Propagation Centre (Devon) has been quarantined 10 metres away from Winkworth’s own small nursery. Among the species delivered are flowering hawthorn (Crataegus) for planting under the oaks, a lime-leaved maple (Acer distylum) and rowan/whitebeam (Sorbus).

Winkworth once held the National Collection on Sorbus Hill. “Increasing our Sorbus collection is a nod to Dr Fox. He wrote the Sorbus monograph included by W J Bean in his book, Trees and Shrubs – Hardy in the British Isles.”

These last hours have flown by and Graham explains why he was happy to walk. “We don’t often get time to look. We are trying to get familiar with every single tree, which is why I like doing this. All too often you can have your head down and miss an entire day just going from job to job. You can’t do that in a place like this. It is too beautiful.”

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