Why New York’s High Line demonstrates one-track thinking

The much-admired plantings on the New York High Line are now in their fifth year of public viewing. Later in the autumn, another half mile will be opened beyond the present mile-long promenade along the former rail line on Manhattan’s West Side. The project attracts up to 5m visitors a year and has changed the profile of housing and development around it. So far, it has not attracted me, as I work to a five-year rule. If there are planting problems, they start to show then. A couple of weeks ago I gave the scheme a plantsman’s critical scrutiny.

Under a hot morning sun the humidity was rising to 100 per cent in the Meatpacking District. At the entrance on Washington Street, I met Thomas Smarr, now in his second year as director of horticulture for the scheme. I arrived with questions. Why are the plants not labelled? Are the beds too narrow? How much does it cost to maintain, before London tries to apply a similar idea on a new bridge over the Thames? What about the colour schemes? The brochure of the Friends of the High Line proclaims that they “seek to engage the vibrant and diverse community on and around the High Line”. What about wildlife and weeds? What about the most vibrant wildlife of all, two-legged humans for whom urban green spaces are deep cover for drugs and sex?

“Up here,” Smarr reassured me, “everything is overlooked. There is nowhere to hide. Maybe people kiss, but nobody is a public nuisance.” The High Line is a popular choice for a date, as newly met couples walk along it, chat and relax for free. It is not a hub for pickups. Can we, then, be relaxed if London follows the same idea? If in doubt, check with a working gardener, preferably one equipped with a weed basket. Up near the High Line’s Chelsea Thicket section, I found Pat, a senior volunteer. I asked her if visitors ever misbehave in the bushes. “The place for that”, she answered, “would be Paris.”

Beyond us, a tall fence of wire netting supported some straggly scarlet-flowered climbing honeysuckle. On the wall of the office building beyond, the wording warned: “The French Aristocracy Never Saw It Coming Either.” Did Pat know something they did not? In fact, she was referring to the Promenade Plantée, a tree-lined walkway in Paris, which was beset by visitor abuse after its opening. The wording on the wall was an advert for a storage business in Manhattan.

Calmly, the Longwood-trained Smarr dispatched my questions into the long grass instead. Since the opening, he knew of only one raccoon and one squirrel that had considered the High Line as a possible home. It is too high up and inaccessible. There are no badgers in the Meatpacking District, although their smoky flesh would make excellent organic sandwiches. There are no urban foxes for a High Line hunt. The last consignment of wildlife on the train line was the final freight load in 1980. The trucks were filled with cold turkeys.

If uninvited diggers are not a problem, what about soil, wind and water? The soil depth on the High Line is only 18in, The main beds are built up about 6in above the walkway but there is no extra depth for the roots of trees. Birch trees seem happy enough so far. Smarr’s main task now is pruning and cutting back. Some of the planting is buried in pots. All of it depends on regular irrigation from a special system. I saw the nozzles in action at midday, sustaining the ground cover beneath evergreen trees. Visitors who think the High Line is an example of “back-to-nature” gardening are wishful thinkers. It is specially planted, regularly weeded and persistently watered. Eight full-time gardeners are doing an excellent job along the walkway. Volunteers like Pat supplement the workforce.

When the plan began, the wild plants of the defunct rail line were assessed to see which, if any, could be used in the new plantings. The working rule was that about half of the planting would use plants native to North America. The recent law for New York City parks dictates that 75 per cent of plants should be native, an absurd restriction that will needlessly curtail the scope for future beauty. The High Line is more flexible, attaching to the fashions for naturalistic landscape and new perennial planting.

After a competition, the brief went to James Corner Field Operations as lead planners, assisted by the ubiquitous Dutchman, Piet Oudolf. When faced with a mile of planting, high above ground, he came good. I salute him for his scheme’s success. Even in July the dominant colour is fresh green, broken only by blobs of his brown-leaved hallmarks with names like Heuchera Brownies. The grass-to-flower ratio is at the higher end of the Oudolf scale, but in a scheme of simulated “natural” planting, the grasses do a closely-knitted job. In autumn, said Smarr, the planting becomes much more vivid, from the red-orange leaves on young Sumach trees to drifts of flowery asters. The plant list includes bulbs for spring, not just native bulbs, either, but 10 types of tulip and even that ice-white crocus Ard Schenk, named after the Dutch speed skater.

I cannot see that the beds are too narrow. I much like their zigzag shape and the way they taper with little channels into the hard surfacing. Nobody planned for the crowds who now flock to the walkway, but as it was not too widely planted, it is not a victim of its own success. The printed plant lists are excellent and the absence of labels is a relief. They would look intrusive and would merely allow one-upmanship by bossy dates with sharp eyesight. Keen plantsmen can consult the list. I admire the whole scheme, the wooden-slatted deck chairs, the big-leaved “native” magnolias at Chelsea Thicket and, above all, the variety of sections, differently planted to change the mood as one walks along. The new section is partly built over, Smarr told me, but partly planted for more colour. Here, I can only applaud.

The High Line planting works as High Line planting, in a special setting with a brief to recall the “natural” planting of the former rail track. It is certainly not “the” way forward for gardeners or some sort of style “breakthrough”. To ensure adequate cover, the plants had to be packed in at high density as small plugs. Calling the result a “matrix” does not make it a new secret for gardeners. It would cost a fortune for amateurs to introduce. The running costs of the High Line are $8m a year, Smarr explained, which is a tribute to its valiant fundraisers, friends and admirers, but not exactly the budget for a newly bought country bolt-hole.

As I walked on, I missed so many obvious friends. Why no lovely blue flowers? Why only one gesture in a mile to any yellow in flower? Why no tall drought-resistant campanulas, hemerocallis, wild hollyhock alcea and so much else? Does it all have to be stale pink, with Astilbe Vision in Pink looking in the heat as if its browned plumes have been used for wiping by a passing rabbit? The High Line “edits” nature, Smarr explained. I found myself editing the present scheme. There is too much grass doing nothing much and too little that brightens the soul, even in hot sun. Even on a rail track, wild nature does not run only to stale pink and lilac-mauve.

Photographs: Iwan Baan