Sister publication Garden Center spoke to William Moss, an urban gardening expert with the National Gardening Association, about rooftop gardening.
His top 10 roofdeck plants:
Amelanchier alnifolia 'Regent'
Aurinia saxatile (basket of gold)
Columbine (Aquilegia cultivars)
Gaillardia 'Frenzy'
Hyssop (Hyssopus officinalis)
Lilium cultivar
Ornamental peppers
Portulaca grandiflora
Rain lily
Rosa Ring of Fire
His top 10 low-maintenance roofdeck plants:
Agave (frost-tender species and cultivars)
Aloe (frost-tender species and cultivars)
Cercidium Palo Verde (frost tender)
Hesperaloe (Red yucca species and cultivars, some frost tender)
Hylotelephium cauticola (upright sedum and cultivars)
Jovibarba (beard-of-Jove)
Sedum (S. album, middendorf, kamschaticum, rupestre, acre and cultivars)
Sempervivum (hen and chicks)
Tulipa tarda
Yucca
Read the rest of his interview here.