When you consider what the roots of even small, "fragile" plants can to to asphalt and concrete and natural rock, it is not in the least incredible that a large mature bulb in a porous medium can move itself to its desired level. Most of them have had millenia to work out various strategies to accomplish this. In my climate, any outdoor bulbs are left to fend for themselves and, often, I find that transplanting them involves a lot more digging than the original planting. Rand In The Great White North >I'm with Diana here. I tuned in late, went back and am amazed to find that >some astute growers don't think bulbs can pull themselves down. Maybe our >conditions are very different!