July 2011 issue of the Cornell Flower Bulb Research Program Research Newsletter:
In this newsletter, we will focus on the 0” planting depth plots, based on 3 years of flowering. Essentially, this was a “top planting” or a “drop and cover” approach. The idea is simple: till the area, place bulbs on the tilled soil (no digging!), then cover with 2-6” of mulch. While this is an easy way to plant, we were interested to find out whether this would reduce the perennialization potential of the bulbs. What we found Quite simply stated, “top-planting” and mulching was found to be an excellent method to plant tulips, and to also allow their perennialization.