#A detailed description of Hydrangea macrophylla ‘Mini Penny’ follows. Colors are based on The Royal Horticultural Color Chart (1995). All measurements/characteristics were taken from a 2-year-old plant in a 27 liter nursery container grown out of doors under 50% shade at Dearing, Ga. (USDA zone 7.b). Plants grown outside flag under full sun, and 30% to 50% shade is recommended. Measurements of leaves/stems and floral characteristics are based on 10 to 20 samples. Classification: Botanical.—Hydrangea macrophylla (Thunb.) Ser. ‘Mini Penny’. Parentage.—Open-pollinated seedling of Hydrangea macrophylla ‘Penny Mac’. Propagation.—Vegetatively by cuttings. Plant: Size.—On average 41 cm high, 91 cm wide in 2 years. Habit.—Mounded deciduous shrub, multistemmed and extremely compact. Branching.—Many breaks (shoots) from base of one-year plants, ie, freely branching. The plant is highly resistant to insects and diseases, including mildew. Leaf: Shape.—Ovate. Base.—Cuneate. Apex.—Acute. Size.—Length 13.9 cm, width 7.7 cm. Arrangement.—Opposite. Margin.—Coarsely serrate. Texture/substance.—Thickish; glabrous on upper and lower surfaces; 6 to 8 prominent raised vein pairs on lower surface. Petioles.—1.40 cm long, glabrous, grooved above, rounded below. Color: Yellow-Green Group 145A. Mature leaf color.—Summer color varies with nutrition and intensity of sunlight. Upper leaf surface typically Yellow-Green Group 147A; lower surface Green Group 137C. Lower leaf surface veins are Yellow-Green Group 145A. Stems: Length.—Stems varied in length from 17 to 48 cm, with an average length of 30 cm. Thickness.—0.4 cm. Texture.—Slender, terete, glabrous, lustrous. Internode length.—2.8 cm. Color.—Yellow-Green group 145A. Hardiness.—USDA (1990) Zone 7 (−17.8° C. to −12.2° C.) to 9 (−6.7° C. to −1.1° C.). Vigor.—Slow, 2-year old plants range from 38 to 51 cm tall by 76 to 102 cm wide. Inflorescence: Bloom period.—May to November, Athens and Dearing, Ga. Flower arrangement.—Corymb, mophead, with sterile florets (sepals) covering the fertile flowers in the interior. Shape of inflorescence.—Rounded. Inflorescence size.—9 to 11 cm diameter with the average depth of 6 cm. The number of fertile flowers per inflorescence varies from 16 to 18. Floral buds.—Immature buds are round, 3 mm long by 3 mm wide by 2 mm deep, and are Yellow-Green Group 145D. Mature buds are round, 4 mm long by 4 mm wide by 3 mm deep and are Purple Group 75C. Peduncle.—Range in length from 10 mm to 15 mm and approximately 1 mm in diameter. Color is Red-Purple Group 62B. Pedicil.—The pedicil of the fertile flower has an average length of 2 mm with 1 mm diameter, and are Greyed-Purple Group 185D. The pedicils of the sterile florets vary in length from 5 mm to 15 mm with 1 mm diameter, and are Red Group 65C. Fertile flowers.—Insignificant and hidden by sterile florets. The immature fertile flowers are Yellow-Green Group 145B, with five stamens and five petals. The mature petals are elliptical and cupped, 3 mm long and 2 mm wide. The color of the upper surface of the mature petals is Purple Group 77C and the lower surface is Purple Group 76C. Sterile florets.—Four sepals per cluster (showy floret), 2.45 cm diameter; each sepal —glabrous, apex acute to rounded, sometimes notched, base rounded, rounded in outline, entire, 1.5 cm long, 1.4 cm wide. Color.—Sterile florets on plants not treated with aluminum sulfate: Upper surface Red-Purple Group 73D grading to Red-Purple Group 72C at base of sepals, lower surface Purple Group 75B to Purple Group 75C to Purple Group 75D. Sterile florets on plants treated with aluminum sulfate (42 grams per 3.8 liters of H2O applied as soil drench when flower buds were visible) Violet-Blue Group 95C grading to White Group 155D at base of sepals on upper surface and Violet-Blue Group 94C to Violet-Blue Group 97A on the lower surface. Fragrance.—None noted. Persistence of inflorescence.—2 to 3 months. Reproductive system: Fertile flowers.—One pistil with 3, occasionally 4, stigmas, and 5 stamens on fertile flowers; pollen: white. Fruit.—Fertile capsule, urn-shaped, 0.5 cm long, 0.3 cm wide, Brown Group 200B. Each capsule contains 50 to 200 sheets which are approximately 0.5 mm long by 0.25 mm wide, with color Greyed-Orange Group 164C.