Scientific Name (Genus/Species): Heuchera americana

Family: (Saxifragaceae)

(P) to 2′. Rock Geranium, Coral Bells. A native to eastern North America with attractive, mottled, palmately lobed simple leaves. Small, five-petalled, white flowers on upright slender racemes bloom in early summer. Partial shade. 4 & T2

Scientific Name (Genus/Species): Heuchera villosa var. macrorhiza

Family: (Saxifragaceae)

(P) to 2′. Giant Maple-leaved Alumroot. Appalachia. Lush clumps of large, fuzzy, sharply pointed, palmately lobed, apple-green leaves are topped with airy sprays of small, creamy white flowers. Blooms late summer and well into fall. A most welcome sight at the end of the season. Moist, well-drained soil. Sun/partial shade. 4 & T2

Scientific Name (Genus/Species): Hibiscus moscheutos subsp. palustris Pink

Family: (Malvaceae)

(P) to 7′. Swamp Rose Mallow. Eastern US. It is hard to believe this robust, lush-foliaged plant with incredible saucer-sized, rose-pink, crepe-paper blooms is in fact a hardy native. Late to emerge in spring, but once they do, they grow quickly and so require a moist fertile soil to really thrive – the edge of a pond or marsh, rich in organic matter is ideal. Late summer bloomer. 1 & 2B, then 3 & T2

Scientific Name (Genus/Species): Hibiscus moscheutos subsp. palustris White

Family: (Malvaceae)

(P) to 7′.  Swamp Rose Mallow.  Eastern US.  A lovely white version of the above with a dark pink centre.  Late summer bloomer.  1 & 2B, then 3 & T2

Scientific Name (Genus/Species): Hibiscus trionum

Family: (Malvaceae)

(A) to 2′.  Flower-of-an-Hour.  East Mediterranean.  Cup-like, two-inch, creamy yellow, five-petalled flowers with dark burgundy centres and orange stamens.  Inflated, translucent, five-sectioned seed pods with purple veins persist.  Simply beautiful.  Sun.  3 & T2

Scientific Name (Genus/Species): Horminum pyrenaicum

Family: (Lamiaceae)

(P) to 9″.  Dragon-mouth.  A native of the Pyrenees to the Tirol with bronzy, quilted and scalloped basal foliage resembling Ramonda.  Upright spikes of hooded, blue-violet flowers with fish-like mouths with purple and white interior striping.  A beauty.  Blooms early summer.  Well-drained soil.  Sun.  3 & T1

Scientific Name (Genus/Species): Hosta sieboldiana var. elegans

Family: (Asparagaceae)

(P) to 3′. “…most sumptuous of all the Hostas.” (GST**).  Huge, broad, glaucous, heavily textured, bluish green leaves form magnificent, stately clumps that add accent and poise to the woodland garden.  Pale lilac-white flowers appear in early to midsummer, though they barely emerge from beneath the foliage.  3 & T3, then it may need 40º for 2-3 months.

Scientific Name (Genus/Species): Hydrangea quercifolia

Family: (Hydrangeaceae)

Shrub to 8′. Oakleaf Hydrangea. This native of Georgia and Tennessee southwards is one of our all-time favourite “must have” shrubs. Forming full, rounded mounds of lobed and scalloped, oak-like leaves, it is graced in June with showy almost conical foot-long inflorescences of creamy white, often fading to soft pink with age. In fall, the large coarsely textured leaves develop rich hues of purple, scarlet and orange, providing some of the most vivid of autumnal colour. It grows better for us in some shade and with winter protection, as one would except from this southern belle. Prefers a moist, acidic but well-drained woodsy soil. 5 & T2

Scientific Name (Genus/Species): Hypericum ascyron

Family: (Hypericaceae)

Hardy shrub to 5′. Great St. John’s Wort. Asia and northeast United States. Two-inch, pale yellow, five-petalled flowers bloom in June against a backdrop of small, pale green leaves. Large seedpods follow. Attractive vase shape. Sun. 3 & T1

Scientific Name (Genus/Species): Hypericum frondosum

Family: (Hypericaceae)

Hardy shrub to 5′.  Golden St. John’s Wort.  A North American native.  Distinctive, blue-grey foliage with 1½-inch, yellow, reflexed petals and a massive tuft of stamens complemented by a statuesque stigma.  This rounded shrub blooms in July.  Ornamental fall fruit changes colour from rosy pink to black.  Sun.  3 & T1

Scientific Name (Genus/Species): Hystrix patula

Family: (Poaceae)

(P) to 5′. Bottlebrush Grass. This American native is widely adaptable, growing in sun or moderate shade, in clay or rocky soil. When the flowerheads open, the spiky florets stick out at right angles, just like a bottlebrush. Attractive until frost. Easy from seed. 4 & T1

Scientific Name (Genus/Species): Impatiens balfourii

Family: (Balsaminaceae)

(A) to 5′. A lovely Himalayan Touch-Me-Not. Hooded, white flowers are flushed pink and display an inflated, elongated, incurving honey spur. The spurred sepal and connate anthers capping the stigma are unique. Seed capsules explode at a touch and self-sow readily. Carefree. Flowers all summer. Sun/partial shade. 3 & T1

Scientific Name (Genus/Species): Impatiens glandulifera ‘Alba’

Family: (Balsaminaceae)

(A) to 7′. A Himalayan native with cool white flowers with short spurs on a many-branched, succulent plant. Long, spear-shaped leaves are sharply serrate. Tall, choice and beautiful. Moist soil. Self-sower. Partial shade. 3 & T1

Scientific Name (Genus/Species): Indigofera kirilowii

Family: (Fabaceae)

(P) to 3′.  Kirilow’s Indigo.  Korea, northern China, southern Japan.  A suckering deciduous subshrub featuring compound, pinnate, bright green leaves and rose-pink, pea-like flowers arranged in dense racemes. Graceful Wisteria-like blooms and fine-textured foliage make for a showy display from early to midsummer with intermittent rebloom through autumn.  The bright green foliage turns a golden yellow in fall.  Performs well in mixed borders or as a foundation plant.  Hard winters may kill stems to the ground, but the plant blooms reliably on new growth each season.  Sun.  2B & 3, D & T2

Scientific Name (Genus/Species): Inula ensifolia

Family: (Asteraceae)

(P) to 18″. Swordleaf Inula. Eastern Europe. A sturdy little plant with narrow, stalkless 4″ leaves on erect branching stems carrying terminal, solitary golden yellow daisies. Very likable. Blooms mid-summer onwards. Sun. 4 & T2