Have you enjoyed watching your tulips bloom? Have you noticed that they are starting to bunch together? Tulip bulbs divide, and a flower comes out of each bulb. Simply divide the bulbs and re-plant.
After tulips have bloomed for the season, it is easiest to divide bulbs while you can still see this season's growth. If you have bunches of tulips, as pictured, these are bunches that have not been divided. Each year the bulb grows more bulbs and a flower will come from each bulb. If you break them up (like toes in a garlic bulb) and plant each bulb in new locations it will eventually grow into another bunch to be divided in a few years. Dividing them every few years will actually give them more space and make them more prolific! Don't worry about waiting until fall to plant the bulbs. Keeping them out of the soil will potentially expose them to airborne disease (mold) and/or drying out... or you just may forget to plant them. Lastly, be careful with bulb planting and dogs - the bulbs are sweet-tasting/smelling and unfortunately poisonous to dogs... so don't leave them out where dogs can find them, but also keep dogs out of newly planted areas or they might dig them up and eat them.