perennial list: q-r

Rhubarb-Canada
Red
Rheum rhabarbarum

3/3 ft.
1/1 m.

Sun or shade.

Green.

White.

May to Sept.
Zone 2.
Well-drained.

Rock or Sun Rose
Helianthemum
nummularium

12/24 in.
30/60 cm.

Sun.

Gray-green.

Various.

June to Sept.
Zone 4.
Well-drained.

Rodgersia
Rodgersia pinnata

4/3 ft.
120/90 cm.

Part shade.

Purple bronze.

Pink.

July.
Zone 4.
Moist.

Rudbeckia-Gloriosa
Daisy
Rudbeckia nitida

6/3 ft.
200/90 cm.

Sun.

Green.

Yellow.

July to Sept.
Zone 2.
Well-drained.

Rudbeckia-Gloriosa
Daisy
Rudbeckia hirta
Rudbeckia fulgida

36/18 in.
90/45 cm.

Sun.

Green.

Yellow, orange, bronze.

July to Sept.
Zone 3.
Well-drained.

Rue
Ruta graveolens

16/12 in.
40/30 cm.

Sun.

Blue-green.

Yellow.

June to August.
Zone 4.
Well-drained.

Russian Sage
Perovskia
atriplicifolia

4/2 ft.
120/60 cm.

Sun.

Gray-green.

Blue-violet.

July to Sept.
Zone 4.
Well-drained.