building up a flower bed over bulbs and perennials

by Kim P.
(Austinburg, OH)

I have an established flower bed where crocuses, balloon flower, daffodils and tulips grow back every year. The bed is in need of building up and typically I would add more topsoil. Can I, instead, add lasagna layers, after the plants have died back? Will the bulbs and plants grow back through the layers next year? Or will they get smothered with not enough air and light? I need to add about 6 inches or more of material, either topsoil or layers. I would rather do the compost layers, since that would be cheaper.