Did you know that in 17th century Holland, you could buy a house or a farm field for a handful of tulip bulbs? Not because property was dirt cheap, but because tulips were that valuable.
The Dutch people had become infatuated with the flower bulbs that originated in Turkey, and by the 1600s, tulips were so pricey that the average bulb sold for the equivalent of a tradesman’s yearly salary. The tulip financial bubble eventually popped, of course, but what became historically known as tulip mania endured for the Dutch.
When tulips are blooming in spring, many of us wish we had planted more of them last fall. Tulips follow the rule of other perennials: the best time to dig, divide or plant is during the season opposite the perennial’s bloom time, which is why we plant tulips or divide the bulbs in fall.
Although fall is the time for planting new tulips, the care we give existing tulips now in spring determines whether they’ll bloom well next year, or whether the bulbs will weaken and fizzle out. Large, healthy bulbs have enough food and energy stored within to ensure vigorous blooms the first spring. Our job as gardeners is to rebuild the bulb’s energy after blooming.
Tulip botany helps us understand why spring care is vital. As tulips finish their spring flowering flush, the leaves of the plant feed the underground bulb in preparation already for next year’s growth. Forming deep within the bulb are tiny leaves and future flower buds. The potential size and strength of these tiny flowers-waiting-to-happen depends on good nutrition. After their spring work is completed, tulip leaves turn yellow, wither, and die away.
Here’s what to do in spring so tulip beds will continue to flourish:
- While tulips are blooming, keep them well-watered during dry periods, especially if they are planted near a building’s foundation, where the soil tends to dry out.
- As soon as tulip flowers fade, remove them by cutting right below the withered blossom. The flower stalk can be left on. Removing the spent flowers prevents a seed pod from forming, which needlessly saps energy.
- Fertilize the tulip bed with a granular, well-balanced 10-10-10 fertilizer at the rate of one-third to one-half cup per 10 square feet of flower bed. This is a vital step in providing the nutrition tulips need to replenish themselves after spring’s flower flush. Water after fertilizing, to activate the granules.
- Water-soluble fertilizer, such as Miracle-Gro, can be used in place of granules if desired, applied every 10 days while leaves are green and active.
- Tulip leaves are manufacturing food while they’re green and healthy. Don’t remove or cut back any foliage.
- Leaves will eventually turn yellow, then brown and withered. When leaves are dry and crisp, they can be removed, and the bulbs then remain dormant from midsummer on.
- Some gardeners plant annual flowers close to the tulips to provide color after the tulip foliage disappears.
- Tulip varieties differ in their longevity. Darwin hybrids tend to thrive from year to year better than others.
- Tulips bulbs remain healthier if soil is rich in organic material like compost or peat moss. Heavy clay and light sandy soil both benefit from incorporating two-to-three inches of organic material. Established tulip beds can be top-dressed with organic material, and lightly worked into the surface.
- Tulip bulbs require digging and dividing every two to four years on average, in September or early October.
- Give tulips another application of fertilizer in fall, as they produce roots in preparation for the following spring.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at email@example.com or call 701-241-5707.