A garden awash with brilliantly coloured double tulips, all open on a sunny, spring day, is magnificent to behold. Larger and fuller than single-flowering varieties, these tulips are definitely a double delight.
At last count, there have been about 5,600 tulip varieties, about half of which are still available today. These are grouped into 15 divisions (broadly based on flowering season and flower shape), including two divisions of double blooms—the Double Early and Double Late (sometimes also called Peony) Groups.
Many novel tulip varieties, including most doubles, have developed from natural mutations known as sports. A sport often goes on to produce more sports, so you can end up with clusters of tulips of similar height that flower at the same time but have a range of different colours or markings.
Double Early tulips have large blooms up to eight centimetres across, with pointed petals on short, sturdy stems 30 to 40 centimetres high. Most start flowering in early spring (mid- to late April), slightly later than Single Early tulips; others bloom from early to mid-spring (early to late May). These tulips are especially favoured for producing brilliant colour effects.
Double Early tulips are predominantly white, yellow or pink to bright red. One of the first Double Early specimens was the fragrant, white flushed with pink ‘Murillo', introduced in 1860. It, in turn, has produced 140 named sports, of which about 20 are still available. Their wide colour range (including orange and various combinations) is also impressive. ‘Murillo' sports can be grown as bedding tulips in a rainbow mixture.
Double Late tulips have larger (to 12 centimetres across) flowers with rounded petal tips, most resembling those of peonies. Petal colours range from white through lilac and pink to very dark red or purple, on stems between 15 and 60 centimetres tall. Specimens of the Double Late Group, according to the Netherlands Flower Bulb Information Centre, have been around for centuries. The so-called ‘Yellow Rose' was being grown in 1700, and in 1750, a red-pink double called ‘Marriage de Ma Fille' was also being cultivated.
Do you dig?
Although many gardeners leave tulip bulbs in the ground until the bulbs decay and no longer produce flowers, you can prolong the show in your garden for several years by digging them up every spring after the leaves have yellowed and died down. Separate the bulbs and offsets, then store them in a cool, dry place until next fall's planting season.
Tulip bloom time can vary depending on where the plants are sited. Bulbs in warm, sheltered spots will flower earlier than the same type planted in cooler, more exposed locations.
Plant double tulips in early October, in well-drained, fertile soil. Space them apart one to three times the height of each bulb at a depth three times the bulb's height. Ideally, plant Double Late tulips in wind-sheltered areas (you may also wish to stake individual blooms), as their heavy flowers can be blown over by strong rains and winds. Sited in the right place, they can have a long flowering season in May and early June. Double Late tulips perform exceptionally well in regions with cold winters and late springs.