The spectacular new Great Broad Walk Borders at Kew Gardens are set to put all other borders, private or public, completely in the shade.
It’s not just their length — they stretch a 20-minute stroll from the Palm House to the Orangery and at 350 yards are the longest pair of herbaceous borders in the world — but the dazzling spectacle they produce, with 30,000 garden plants in huge swathes and drifts of colour, selected to hit their flowering peak between May and October.
This is the place to come for inspiration, not just at the start of summer, but right through the season and especially when your own borders are flagging during the dog days of August. At that time, for instance, you will inevitably be seduced by the flirty New Mexican salvias in their carnival pinks and firecracker reds, as well as admire at close quarters, via a series of pathways within the borders — which reach over 15 yards at their widest point — the huge circle of the Compositae plant group that encompasses the finest varieties of daisy flowers, including rudbeckias, heleniums, sunflowers and asters, mildew-free, of course.
Kew’s head of garden design, Richard Wilford, is the man with the plan that took six months of scribbling on probably the world’s longest piece of paper, before transferring the series of circles to canes and landscape spray on the bare ground. Aside from their major petal power, the 220 different varieties of plants that made the final cut comprise quite simply of plants Wilford likes, as well as plants he noted from visiting other gardens, just as we might choose plants for our own rather smaller borders.
The original Broad Walk was landscaped in the 1840s by architect William Nesfield to heighten the drama of the approach to the newly constructed Palm House. “I enhanced the perspective by planting an avenue of 14 four-sided pyramid yews at intervals along the front, which really transforms the space,” says Wilford.
“What also makes a big difference is that now you can wander and sit among the plants, instead of just admiring them from the central path. When we put down the benches, within minutes people were sitting on them.”
Interpretation panels through the planting will give visitors botanical information. But which of the vast selection on display does Wilford especially recommend to give prolonged blasts of colour through summer for London gardens?
“Penstemons are great value, especially bright red Penstemon Firebird which has kept on going from June, and paler, pink-and-white Apple Blossom. If they start to fade, you just cut them back, and off they go again. Alstroemeria Indian Summer, with yellow-streaked orange flowers, keeps going, too, and is very resilient. We had it in another scheme, lifted it, planted it in a nursery bed and replanted it here, and it’s blooming merrily.”
His favourite flower from what’s in bloom right now? “Kniphofia Tawny King. I love the colour, a subtle yellow/orange. It’s been flowering for quite a while, and when it goes over, it will be followed by brighter orange triangularis, which will still be looking great in October. I’ve teamed it with Agapanthus Midnight Star, a deep blue, and added a bit of Russian sage, Perovskia, because it makes a good hazy lavender contrast to the two verticals.”
The perennially popular Geranium Rozanne gets his vote for the longest-flowering geranium, but he also recommends similar Orion, which is taller, and has been going strong since May. “I’ve also used shocking pink Ann Folkard because it scrambles through other plants. I’ve got it growing through sky blue Eryngium bourgatii and lemon yellow Achillea Moonshine.”
Dynamic colour combos abound throughout the borders, such as pink-petalled Echinacea purpurea scarlet popping up among Crocosmia Lucifer, and rust Achillea Terracotta flattering deep blue Salvia Caradonna. Salvias are high on Wilford’s list of top summer performers.
“They’re such useful garden plants, not least because of their length of flowering. We have a salvia border at Kew that looks amazing in September and October. Early salvias were one of the first plants to appear this summer: light blue Serenade, deeper Dear Anja and Caradonna. Later on, less-hardy New World salvias like Maroon and lilac-pink Peter Vidgeon take the limelight.”
Despite their size — and that sensational vista is seemingly endless — the new double borders offer many lessons for gardeners with borders of a more modest size. For instance, those pyramid yews planted at intervals, setting a formal note, could be scaled down to box balls. Wilford also advises: “Have fewer plants, but more of each one. By reducing the number of varieties, you’ll have more impact. Come and look at the borders and see what will work for you.” That’s the best tip of all.
To mark the launch of the new borders, Kew is hosting three celebratory weekends through summer, starting this weekend (30/31 July).