Answer: Herbaceous perennials can be planted in the spring, and if they are container grown, can be planted in summer or fall as well. Bare root material would be only available in the spring and should be planted upon receipt.The bulbs that bloom in the spring such as tulips and daffodils (these are true bulbs) need to be planted the previous fall, or in some cases can also be purchased and planted in bloom in pots in the spring. Most of the summer flowering perennials such as black eyed Susans, Shasta daisies and daylilies are not bulbs at all. However, some of the more popular perennials may be grown from rhizomes (this would include bearded iris) or from bulbs (this would be the true lilies or Lillium) and these can also be planted in spring, summer or fall if container grown, although when sold "bare root" they are best planted immediately.
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