Hosta
(Hadspen Blue) Also known as plantain lily, hostas produce showy sprays of fragrant white or lavender flowers. But gardeners grow them more for their stunning leaves, which unfurl from a central hub in a strikingly tidy way. The leaves are works of art, with crisp patterns on oval, heart or lance shapes. Colors include cream, light to dark green, chartreuse, gray and blue-green. Hostas aren’t entirely carefree, since slugs and snails can pose a problem. To deter them, scatter iron phosphate pellets (sold for this purpose) around plants. Or choose naturally resistant varieties, which have heavily textured or waxy leaves; these include ‘Blue Mouse Ears,’ ‘First Frost,’ ‘Krossa Regal’ and ‘Hadspen Blue.’ The thousands of hosta varieties grow from 3 inches to 5 feet across and up to 3 feet tall. Does best in partial or full sun, with regular water. Perennial in zones 3-9.
Astilbe
(Ostrich Plume) For carefree color in a shady garden, consider astilbe, which produces feathery plumes of white, pink or red flowers from late spring through summer. The rest of the year, the attractive divided leaves effectively block light from reaching the soil, which helps to keep weed seeds from sprouting. ‘Ostrich Plume’ (also known as ‘Straussenfeder’) has arching sprays of pink flowers, while Astilbe x arendsii ‘Fanal’ has erect spikes of bright red flowers. Most varieties grow 2-3 feet wide and around 3 feet tall. Does best in part shade, though full sun is OK in cool areas, with regular water. Perennial in zones 4-9.
Hakone grass
(Hakonechloa macra) This ornamental grass arches in a way that resembles a miniature cascading bamboo. ‘Aureola,’ which has golden leaves streaked with green, and ‘All Gold,’ which has yellow leaves with just a touch of green at the base, light up a shade garden and make a fantastic textural counterpoint to hostas or astilbe. Other varieties have leaves of lime green (‘Lemon Grass’) or red and green (‘Beni Kaze’). Plant as a border or use as a ground cover over a wide area. Grows 12-18 inches tall and 18-24 inches wide. Needs moist, well-drained soil. Perennial in zones 5-9.
Common lilac
(Syringa vulgaris) Hardy and trouble-free, these deciduous shrubs produce huge clusters of fragrant white, pink or purple flowers in mid to late spring. If you want something showier than your grandmother might have had, consider ‘Sensation,’ with purple petals edged in white. Varieties called French hybrids also have especially showy flowers. Descanso hybrids do well in mild-winter areas where standard lilacs bloom sparsely. Grows up to 20 feet tall and wide. Does best in sun, or partial shade in hot climates, with regular water. Perennial in zones 3-8.
‘Endless Summer’ hydrangea
(H. macrophylla) This is a classic-looking mophead hydrangea with billowy clusters of blue flowers if the soil is acidic or pink flowers if it’s alkaline. But it’s a lot less fussy than most mopheads because it blooms on new or old wood. This means you don’t have to worry about early or late freezes killing the flower buds, or even whether the plant dies back to the ground every year; you’ll still get blooms on the new growth. Also, you can clip spent flowers or harvest fresh ones for bouquets and get repeat blooms into fall. Grows 3-5 feet tall and wide. Does best in partial shade, with regular water. Perennial in zones 4-9.
Rugosa rose
(Rosa rugosa) This super-hardy, mostly pest-free rose is sometimes called sea tomato because it shrugs off salt spray along coastlines and produces red fruit, called “hips,” that resemble cherry tomatoes. Single or double blossoms can be white, yellow, pink, purple or red, depending on the variety. The stems have lots of sharp thorns—good if you want a hedge no one will sneak through. Longtime favorites include ‘Frau Dagmar Hartrpp," a single pink, and ‘Hansa,’ with double magenta flowers; and purplish rose. Grows 3-6 feet tall and wide. Needs full sun; prefers moist soil but can be fairly drought-tolerant once established. Perennial in zones 3-9.
False indigo
(Baptisia) Native to the East and South, this flowering plant produces blue or white springtime blooms that resemble sweet peas, but on erect stems, not vines. Attractive long seedpods turn black when ripe and persist into winter; they work well in dried flower arrangements. Blue false indigo (B. australis), the 2010 Perennial Plant of the Year™ grows 3-6 feet tall and 4 feet wide. White false indigo (B. alba) is more compact, at 2-3 feet tall and 3 feet wide. Needs full sun; moderate water, but is drought tolerant once established. Perennial in zones 3-9.
New Zealand flax
(Phormium tenax) Unfussy and dramatic, New Zealand flax is grown mostly for its large, sword-shaped leaves, which are often streaked with cream, bronze, purple or rose against a green background. Stalks with red flowers shoot up to 12 feet high in summer. Container-size plants are smaller and usually don’t bloom. Grows 1-6 feet tall and 1-3 feet wide, depending on variety. Prefers full sun to part shade; little to regular water. Perennial in zones 9-11, but will usually regrow from roots if it dies back in zones 7 and 8.
Penstamon
(P. digitalis) Penstamon is often called beard tongue because of the pronounced tongue on its narrow, bell-shaped flowers. The popular ‘Husker Red’ has maroon leaves and light pink flowers. ‘Dark Towers’ is an even more robust and brilliantly colored variety of P. digitalis, which in its basic form is a native of the eastern and central U.S. Both of these varieties grow 2½-3 feet tall; other varieties can reach as tall as 5 feet. Prefers full sun but tolerates light shade; regular water. Perennial in zones 3-8.
Spirea
(Fairy Queen) This easy-to-grow deciduous shrub comes in two basic forms: bridal wreath, with cascading branches covered with clusters of white flowers, and as an erect shrubs, with red, pink or white flowers. S. cantoninsis ‘Flore-Pleno’ is a bridal wreath with double white flowers. S. trilobata ‘Fairy Queen’ also has white flowers, but a more erect form. S. densiflora, or mountain spirea, is a Western native with pink blossoms. Grows 1-7 feet tall and up to 10 feet across, depending on the variety. Prefers full sun to light shade; regular to moderate water. Perennial in zones 3-7, though hardiness varies depending on variety.
Bluestar
(Amsonia) Native to the Southeast, these tough plants have narrow leaves topped by sprays of small, star-shaped blue flowers. Hubricht’s Bluestar (A. hubrichtii) is one of the best. It’s also known a threadleaf bluestar because of its soft, needlelike leaves, which turn bright gold in fall. The flowers are sky blue. A. tabernaemontana has steel blue to lavender-blue flowers. Grows to 2-3 feet high. Prefers full sun to light shade; regular to moderate water. Perennial in zones 4-10.
Goldenrod
(Solidago) Plant goldenrods and your summertime garden will wind down in a blaze of glory. S. rugosa ‘Fireworks’ has arching wands covered with bright yellow flowers, as if they were the sparkling trail of a rocket. ‘Goldenmosa,’ a Solidago hybrid, produces erect bouquets. Goldenrod is often blamed for triggering hay fever, but that blame really goes to ragweeds (Ambrosia species), which bloom about the same time. Most goldenrods grow 1½-3 feet tall and about 2 feet wide. S. gigantea, or giant goldenrod, towers up to 7 feet tall. Prefers full sun to light shade; moderate water. Perennial in zones 3-9.