Here are various
plants/
flowers to grow in your shady
zone 6... not all purple but just some ideas:
Red Chokeberry (Aronia Arbutifolia.) White
flowers with red berries.
Chelone oblique. These are a baby pink and grow best in semi-shade.
Illumination Commom Periwinkle. Pale blue with yellow- green leaf.
Girard's
rose Azalea. How can I forget- these are a intense, beautiful red.
Camellia japonica '
spring's Promise' in particular. Red.
English Roseum Rhododendron- here's the purple your looking for.
Luxuriant Fringed Bleeding Heart. Red'ish pink.
Purple Gem Rhododenron. Dense shrub but ideal to "take up space". Another purple to consider.
Good Luck!