Some tulips have come up this year with a lot of green leaves but without buds. Are they duds or should I leave them for another year?
In Holland the bulb growers dig up tulips yearly, dry them and replant in the Fall. In North America we tend to treat them as perennials that die off over the years.
In the past have you noted if the tulips get enough sun? Do you allow the leaves to die back, turning yellow before you remove the debris?
You did not state if the tulips have bloomed in the past. Could they be planted too deeply if they have never bloomed. Tulips respond to being fertilized spring and fall. They like rocky soil rather than rich loamy soil. They do not like to sit in water unless they are cut for a vase. If your tulips have been blooming and now don’t, it could be time to dig them up and separate all the bulbs.