Plant more tulips with less effort

'Ad Rem' tulips (foreground) planted on top of tilled soil and covered with mulch. Both varieties used in the study continued to bloom well in the third spring after planting. (Click for larger image.)
'Ad Rem' tulips (foreground) planted on top of tilled soil and covered with mulch. Both varieties used in the study continued to bloom well in the third spring after planting. (Click for larger image.)
A three-year study by Cornell University’s Flower Bulb Research Program (FBRP) shows that “top-planting” is an excellent way to save labor while planting tulips — as well as to help them come back and bloom well for several years.

“Gardening is good, healthy exercise, and avid gardeners enjoy being outside planting bulbs in the fall,” says Bill Miller, professor in the Department of Horticulture and FBRP research director. “But ‘top-planting’ can make bulb planting easier, allowing you to plant more bulbs with less effort.”

The planting technique, also known as “drop and cover,” isn’t new, notes Miller. It’s just underused. He suggests gardeners and landscapers:

  • Till the planting area 3 to 4 inches deep with a rotary tiller.
  • Spread bulb fertilizer and if possible till again.
  • Place bulbs on top of the tilled area. (Resist the urge to press them in as this could damage the bulb base.)
  • Cover with 2 to 4 inches of aged mulch or well rotted compost.

Avoid over-mulching, cautions Miller. Plots that received 6 inches of mulch had the least blooms by the third year of the study.

Miller used two tulip cultivars ‘Ad Rem’ and ‘Negrita’ known for their ability to perennialize (regrow and rebloom for several years after planting). While many people grow tulips for just a single season before ripping them out, in 2011 both cultivars still produced an average of at least one flower per bulb planted three years earlier.

“By the third year, all plots had at least two groups of plants,” notes Miller. “Some of the plants were extremely large growing from large bulbs underground, and others were shorter, producing an ‘understory’ of color.”

“Our work has shown that gardeners can enjoy masses of tulips without the work of digging a hole for each bulb,” he adds. “We used ‘double ground bark mulch,’ but any good garden mulch should work equally well. We have had excellent return of tulips for at least three years with this method. And no digging!”

Read research report.

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