Tulip fever is once again upon us. But for many gardeners, the bulbs bulk-bought in autumn will bloom just once, never to return. This is because we are not planting and nurturing them correctly, says Jacqueline van der Kloet, a garden designer and bulb specialist. Tulips are not difficult, they just need more careful handling than other spring-flowering bulbs such as daffodils, muscari and crocuses. In some of her many projects around the world, Van der Kloet has planted tulips that have rebloomed for 12 to 15 years.
Bulbs — particularly tulips — are a crucial element of Van der Kloet’s designs and in her own garden in Weesp, the Netherlands, which features in her new book My Garden: A Year of Design and Experimentation.
While tulips can be unpredictable, says Van der Kloet, there are a number of tactics and choices that will encourage a long-term presence. “Species tulips are stronger but there are a lot of long-stemmed, cultivated tulips that I have found very good for perennialising,” she says, citing Yellow Purissima, pink Don Quichotte, red Parade and Apeldoorn, lilac Violet Beauty and deep purple, beetroot-veined Negrita.
She loves to eschew convention. In the Dutch bulb garden at Keukenhof she combined yellows, oranges and pinks, “because people always say that those colours don’t go together. But when you add enough green in between and a little bit of red they can go very well together. I like to show how you can play with colours”.
To become perennial and return again each year, tulips need to be planted in time to develop their roots, and then, after flowering, left in place and the bulbs replenished with nutrients. This means planting them 15cm deep in November in a sunny, dry spot. Once foliage begins to poke through the ground in February, Van der Kloet advises applying fertiliser.
“Tulips open their flowers when the sun reaches them in the morning and at the end of the day they close them. At the end of their flowering period they don’t close any more at night and that’s when you have to deadhead,” she says. But, importantly, “leave the stem and foliage to wither naturally”. As with all bulbs, they need their foliage to photosynthesise and build up food stores to flower again the following year.
Tulip bulbs also need to stay dry when dormant, which is where many gardeners go wrong, she says. “Don’t overwater your garden,” she cautions, highlighting the hazards of sprinkler systems — “when the soil is wet all the time, that kills the tulips.”
One further impediment is all too human: the main planting time for spring-flowering varieties is in the autumn, when “many people are tired of tending the garden all summer long and don’t want to plant any more”, she says. However, if you leave planting until after Christmas you risk failure, she says: bulbs harvested back in the summer have depreciated in quality and will not have adequate time in the ground to grow frost-resistant roots.
Van der Kloet is a frequent collaborator with fellow Dutch garden designer and “new perennial” proponent Piet Oudolf. For his Lurie Garden in Chicago, created in 2004, she added 125,000 spring and summer-flowering bulbs to his 25,000 perennials. They have learnt a great deal from one another, she says.
“His schemes are more powerful, with bigger clumps of plants and huge grasses, whereas my plantings are more delicate,” she says. Her bulbs introduced colour to the schemes earlier in the season. “Piet has learnt from me how to do that, because in the beginning he didn’t use any bulbs. I have learnt from Piet how to adapt to a planting scheme, to try to create in bulbs the same atmosphere as his planting, using taller and bigger bulbs.”
Despite its name, her book is not so much a 12-month diary of her garden at Weesp as an accumulation of her experiments and experience to date. She has been using bulbs for 30 years, drawn to their ability to brighten a garden when everything else is dead. She soon, though, rejected “the old-fashioned way of planting” in clumps. “It looks good when it’s flowering,” she says, “but after flowering there’s a hole in the border because there’s nothing to replace them.”
Instead, she advises mixing bulb varieties together then throwing them among existing plants, burying them where they land. A more naturalistic look can also be achieved by choosing a smaller number of types, in larger quantities.
“People often order 10 or 15 different varieties, and 50 or 100 of each,” she says, but a better effect can be gained with 200 or 300 bulbs of four or five varieties. “The effect and balance are better than when you have all different colours, heights and varieties.”
Van der Kloet’s favoured groupings include white, pink and blue forget-me-nots with tulips or hyacinths; maroon and white tulips with white daffodils and blue camassia; blue Anemone blanda with white muscari; or pink and lilac dahlias with purple Liatris spicata.
Ultimately, have fun with experimenting, she suggests. “I think of it as making a bouquet. The main ingredients are perennial plants, then you want to add something to make it more exciting. So you add bulbs and annuals, and the bouquet comes together.”
“My Garden: A Year of Design and Experimentation” by Jacqueline van der Kloet; Timber Press, £35
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