Gaillardia 

Garden Phlox

Gas Plant

Gaura

Gayfeather

Geranium 

Geum

Globe Thistle 

Goat's Beard 

Golden Alexander

Goldenrod

Grasses 

Great Blue Lobelia

Heartleaf 

Heliopsis

Helleborus

Heuchera 

Heucherella

Hibiscus

Hosta

Hyssop