Castlefield Viaduct: What to expect from landmark green space

It’s all coming up Castlefield. Emphasis on the up. You don’t need to look far in this part of Manchester for exciting things up high. Be it Manchester International Festival’s looming brutalist arts space, The Factory or Soho House Manchester’s rooftop pool. Now you can add Castlefield Viaduct to the list of elevated gems with more details revealed of what visitors can expect.

It’s really important for our cities to have urban parks

The landmark urban space or “sky park”, which is set for an end of July opening, will bring over 3000 trees, flowers and shrubs to the former railway viaduct. The temporary park will take up half of the 330-metre viaduct, first built in 1982 by Heenan & Froude (same engineers as Blackpool Tower). The National Trust is not ruling out extending the urban greenspace if the current pilot scheme proves successful. 

A free community space in the sky

First things first, budding visitors will be pleased to know that entry to Castlefield Viaduct will be free (for the first 12 months at least). No membership required. The space will be open seven days per week, year-round with select closures for maintenance and seasonal garden upgrades. Five, 45-minute slots, roughly a hundred tickets per day, will be available to book with guided tours (between 11am until 3pm) talking visitors through the project, heritage and plant life on display.

The front of the site will be screened from the public in order to give a secret garden feel, with the route through the garden passing an initial experimental planting area before opening up into a native garden with an events space and “show garden” positioned at the back.

Due to engineering constraints (it’s an old structure, all this stuff is heavy), groups will be limited to 20 with no more than 50 people allowed in the events space at one time. Yoga, community meetups, food and drink festivals and a host of other events are currently being planned.

As well as providing a much-needed platform of green in a concrete and glass cityscape, the garden will be a celebration of the industrial heritage of Castlefield and Manchester. The design of the planters (lifted in by crane) gives nods to the curvature of the viaduct itself with subtle patterns along the side referencing railway signal points. Each is the width of a railway track.

Visitors will be able to look out over the remaining stretch of untouched viaduct at back end of the garden to see what the infrastructure has looked like since its closure in 1969. Wild strawberries and mountain ash are common on this part of the former track. Canopies meanwhile will be created in the garden using 600 half-hardy annual climbers as well as hops and clematis. Artificial shade will also be installed in what is inevitably a glorious suntrap.

Viaduct organisers will encourage visitors to use nearby public transport to attend the garden with no involvement in the adjoining Manchester Central car park. The garden itself will have full disabled access with visitors encouraged to use the Metrolink station lift. Sadly the lift closest to the site will remain out of order.

Not your average National Trust garden

For those who associate the National Trust with country estate properties and traditional horticulture, Castlefield Viaduct will feel like a world away. A landmark project unlike anything else the Trust are involved in. Unlike other Trust properties, the structure itself is owned by the National Highways Historical Railway Estate. The planning and organisation that has gone into the project is impressive.

Whilst the majority of the garden will be contained in planters, the original ballast surface is also being incorporated into the garden with a layer of 280 sandbags built up to varying elevations. This will create a planting surface for a variety of plants including broom, grasses, ferns, sedums, euphorbias, fennel, fleabane, buddleia, liriope, teasle and Phlomis.

The garden will be home to the cotton grass - the county flower of Manchester - as well as ferns species once collected on the nearby moors by Manchester suffragist and botanist Lydia Becker.

Elsewhere, four unique garden sections (known as "partner plots") have been designed and worked on by local community groups including Urban Wilderness, The Science & Industry Museum, City of Trees and Castlefield Forum. These gardens are currently in their final stages of completion and nod to relevant themes.

Urban Wilderness is working with Manchester-based youth mental health charity 42nd Street. Its "Garden of Possibilities" features a geodesic dome and plants including nettle, feverfew and lemon balm - plants with positive effects on mental health.

The Science and Industry Museum, meanwhile, will transport people to the steam-filled skies of locomotive yesteryear. Fluffy white plants like sanguisorba albiflora will channel steam whilst the cascading blue of lobelia will represent the essential place of water in industry. Castlefield Forum meanwhile has worked with the nearby Saul Hay Gallery for a specially-commissioned artwork to form a centrepiece of their partner plot.

Monty Don will be glad to know the entire garden will be a peat-free zone. No doubt he’ll also be excitable at the thought of blossom hedging, hawthorne, birch, underplanting with the red rose of Lancashire and snowdrops in Spring. Sadly, due to urban pollution’s effects on the structure and the use of lead paint, nothing in the garden will be edible.

From one engineering feat to another

To say the project has been and will be a challenge is an understatement. Think of it as one giant garden-themed engineering puzzle. There’s limited shade, limited water and a lightweight compost. Thus ferns and grasses are being used as a pragmatic base layer that will grow quickly. 

“It’s always going to be an experiment. We’re gardening up in the air, in a compost we’ve never used before in big metal planters that are going to heat up.” Pam Smith, Senior National Consultant for Gardens & Parklands at The National Trust says.

The wind will be a challenge too, due to the unpredictable direction it often takes in cities. Plants with small leaves have thus been used in order to avoid moisture loss and the positioning of each has been carefully considered. One entry in and out brings its own challenges too.

Meanwhile, weight on the structure itself is a finely calculated balancing act. Many of the planters are mostly filled with polystyrene with a small layer of carefully formulated lightweight peat-free compost on top. Plants have been carefully selected to make the most of this medium. Only a certain amount of machinery can be in a certain area at one time. Water in the main tank at the entrance is syphoned off by smaller water carriers.

That said, from what can be seen on a sunny sneak peek visit. So far so good.

Raising awareness of green space everywhere

“It’s really important for our cities to have urban parks. These showcases are brilliant but everyone’s got an urban park near them. This isn’t just about one place. It’s about how we can support people to look after their urban parks and I’m hoping that this becomes a little hub to inspire that.” Pam says.

Talk to anyone on the project and they’ll tell you the Castlefield Viaduct is as much of a community involvement scheme and green space awareness project as it is a beautiful, elevated showpiece.

“Most people aren’t going to put on walking boots and go up the Lake District. Their experience of outdoors is their garden or local park. And hopefully coming on here. It’s accessible, achievable, inclusive - we’re doing a lot to get people out to experience it.”

“Cities are great for plants. Cities have botanical gardens. There’s a broader range of plants in cities than in the countryside. From people’s doorsteps, walking here, they’ll pass an amazing array of plants. Manchester street trees are brilliant. This is just part of the journey, I don’t want people to visit and leave thinking about these things, I want this to be a catalyst.”

Castlefield Viaduct, if all goes to plan, is set to open in late July. We’ll keep you updated.

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