I have a lovely bed of tulips beside the house. For two years I have dug bulbs out of the bed. The first year to thin out part of the bed and the second to dig up Jerusalem Artichokes. Both years I dug down at least eight inches and pulled some bulbs from under the sidewalk. Most of the bulbs I found were close to eight inches deep. In the spring, there are neat rows of tulips I planted and clumps of stronger plants I missed. Would the bulbs have been planted that deep?