Bells of Ireland is a hardy annual (meaning it prefers cooler temps and can tolerate some frost) and is must-grow for bouquet makers. I have had a picture of this unique bouquet greenery hanging over my bed for nearly 2 years! The green spires top out at 2-3'. When they are done providing their awesome foliage in mid-July, replace their spot in the garden with sunflowers to keep the blooms coming.