They seem to be done. How long do I wait before cutting off the dry brown plant left above the soil? I think I need to be sure they have completely fed the bulb below the soil.
Cut the spent flower head off the stem with clean shears. Remove the stem at its base for tulips grown as annuals. For perennials, leave most of the stem in place since the green stem also collects energy for the bulbs.
Trim back the remaining flower stem on perennial tulips once it begins to yellow or fall over.
Remove the foliage on perennial varieties after the leaves begin to yellow naturally. Shear off the leaves at ground level and dispose of the spent plant matter. If you plan to dig and move or divide the bulbs in fall, mark the location with a plant stake so you can find the bulbs later.