The ones I planted are in the opposite type of soil - dense clay - which I've amended repeatedly with cow manure, mushroom compost, topsoil, and peat moss. They do need food if you want to lift the bulbs to store them for next year (many people just buy new bulbs every year and leave the old ones in the ground).
I do lift them, but over the years I've had them overwinter here (Wisconsin, zone 5) if planted in a warmer microclimate such as next to the house. Last year one I missed overwintered quite far from the house, but we had dense snow cover so I believe this saved it. The cormels also frequently overwinter here, a fact I discovered since it is nearly impossible to retrieve them all when digging up their parents.
I usually start planting in late Spring and stagger plantings with a number of bulbs every week thereafter until all are in the ground. With 3 or 4 weeks of staggered planting, I can enjoy glads for a month or so starting in August.