Penstemon x gloxinioides ‘Midnight’ (syn. ‘Russian River’) – The stately spires of this long-blooming Penstemon are borne from late spring through to early fall with deadheading. The deep purple tubular flowers are accented with some darker purple and white in the throats. Unlike many Penstemon, this one is reliably perennial. Grows 2-3′ tall by 2′ wide. Hardy to zone 6
Osteospermum barberiae var. compactum LAVENDER MIST – A truly perennial African Daisy with single 3″ wide blooms that open near white and fade to pale lavender, with darker petal tips. These are borne on 12-18″ tall stalks from May through to autumn with deadheading. Prefers a full sun exposure with good drainage. Drought tolerant. Grows 12″ tall by 15″ wide. Zone 5.
Erigeron x ‘Adria’ – A beautiful Fleabane with fringed strap-like petals of violet accented by a clear yellow center. These are borne over a long period of time (from June to August) and they make excellent cut flowers for the vase. Prefers a full sun exposure with evenly moist but well-drained soil. Pair with Molinia caerulea ‘Variegata’. Grows 2′ tall by 20″ wide. Zone 3.
Salvia nemerosa ‘Caradonna’ – A tall form of perennial flowering sage with thin spires of dark violet-blue blooms held on near-black stems. It flowers from late spring through the summer with regular deadheading. This is a great perennial for nature lovers as it attracts hummingbirds, bees and butterflies. Drought tolerant once established. Grows 24-30″ tall by 18-24″ wide. Zone 3.
Phacelia bolanderi – The Woodland Phacelia or Blue-Flowered Grape Leaf bears pale purplish-blue flowers with white veining around the throat. These are borne from late spring into summer over mid-green foliage which somewhat resembles grape leaves. This perennial can be short-lived but often reseeds. Prefers a partial shade exposure. Grows 6-8″ tall by 24″ wide. Zone 7.