Gaillardia 

Garden Phlox

Gas Plant

Gaura

Gayfeather

Geranium 

Geum

Globe Thistle 

Goat's Beard 

Goldenrod

Grasses 

Great Blue Lobelia

Gromwell

Heartleaf 

Heliopsis

Helleborus

Hemerocallis 

Hen & Chicks

Heuchera 

Heucherella

Hibiscus

Hollyhock

Honey Garlic

Hosta

Hummingbird Mint

Hydrangea

Hyssop