Giant leaves for sunny sites

Mulleins (Verbascum bombyciferum and cvs., USDA Hardiness Zones 5–9) are one of the few big-leaved perennials that offer felty gray leaves, reaching 14 inches long. While all selections of this species are gardenworthy, the largest cultivar, ‘Arctic Summer’, is one of my favorites. It towers at 8 feet when in bloom and spreads like a candelabra. In midsummer, golden yellow flowers ignite its tall, silvery spires. It is truly a sight. Mulleins are a magnificent addition to the garden. Despite their height and branching, they don’t need staking when grown in their preferred conditions of gravelly or dry, lean soil. These plants are evergreen and love drought. For a sure hit, pair ‘Arctic Summer’ with bronze fennel (Foeniculum vulgare ‘Purpureum’, Zones 4–9) and euphorbias (Euphorbia  spp. and cvs., Zones 4–11), or grow it at the back of a hot-colored border. Mulleins tend to be short lived, but do not despair—they seed about obligingly.

Gunnera (Gunnera manicata, Zones 7–10) is the granddaddy of big-leaved perennials. No other plant can so thoroughly alter the scale of a garden while calling such attention to itself. Each thick, hairy, veined leaf grows nearly 5 feet across, and the entire plant stretches 8 to 10 statuesque feet. It erupts from the ground in springtime, with leaves unfolding from thick, hairy, pinkish stems. The conelike, greenish red blooms reach 3 feet high as they pop up in early summer. Gunnera is one weird, colossal plant, intriguing children and adults alike. It requires full sun to partial shade and rich, moist soil. It is particularly happy at the bottom of a wet slope, along the margins of a stream or pond, or in bog gardens. It makes a stellar focal point and is always a “big” conversation piece.

Colewort (Crambe cordifolia, Zones 6–9) is the David Copperfield of the plant world. In full bloom, it’s hard to believe that such cabbagey leaves and thick stems could be topped with such a sweet-scented halo of tiny, white stars. The blooms float ethereally above the foliage for weeks in midsummer, and the 14-inch-wide leaves are impressive all season long. Reaching 3 feet tall and 5 feet wide, mounds of colewort are best used at the middle or back of a border. This is a stunning addition to an all-white garden. It’s effective against a background of evergreens or dark-foliaged plants. Colewort is not a fussy plant. It prefers full sun and fertile soil; it will take partial shade and poorer soil at the expense of size. Slugs have been known to chomp on this plant’s leaves, so be on the lookout for these slimy pests as soon as the foliage emerges in spring.

Dynamic foliage for partial shade

Umbrella plant (Darmera peltata, Zones 5–9) loves a partially shady, moist spot in the garden, where its huge, lily-pad-like leaves can spread. The leaves can reach 24 inches in diameter and look like something from a fairy tale. This plant is sometimes called Indian rhubarb because of its showy, pink blooms. The flower spikes emerge from the ground on naked stems in early spring and are followed by the leaves shortly after. Clumps can reach 4 feet tall and 3 feet wide. In autumn, the leaves turn red, which is more intense in sunnier locations. Umbrella plant spreads by rhizomes and can be aggressive in very moist soil. This characteristic makes it a perfect plant for boggy areas of the garden, where few plants will grow. If you give umbrella plant average, moist soil, its exotically large, rounded foliage will lend a tropical air as it comingles with other perennials in the mixed border.

Rodgersias (Rodgersia spp. and cvs., Zones 3–8) are one of the most handsome perennials around with their wonderfully quilted, palmate leaves. There are several striking species, so it’s hard to go wrong. They generally reach 3 to 6 feet tall and wide. Their fluffy flower plumes resemble those of astilbes and range in color from white to pink in mid- to late summer. Rodgersia aesculifolia (Zones 5–8) is an excellent species with 10- to 12-inch-long leaflets that contribute to each leaf section’s 18- to 24-inch spread. Rodgersia podophylla (syn. R. japonica, Zones 5–8) has bold, toothed leaves that reach 16 inches wide and turn a brilliant red in autumn. The oddball of the group, Rodgersia tabularis (syn. Astilboides tabularis, Zones 5–7), has huge 36-inch-wide leaves that resemble lily pads that just floated ashore. While not a water plant, it does prefer moist, but not water-logged, soil. And like the rest of the clan, it thrives in partial shade but will take full sun as long as it has a rich, damp place to sink its roots.

Ligularias (Ligularia spp. and cvs, Zones 4–8) are another group replete with variation. With plants ranging from 3 to 6 feet tall and wide, ligularias sport 12- to 14-inch-long leaves of exaggerated dimension and golden yellow, daisylike flowers in summer. The most striking plants of the group are Ligularia dentata ‘Othello’ with deep purplish green, kidney-shaped leaves; L. przewalskii with long, deeply toothed leaves and dark purple stems; and the new hot plant, Ligularia ‘Britt Marie Crawford’, with glossy, chocolate-colored leaves with red reverse. Create a color echo along the border with burgundy-leaved perennials like ‘Chocolate Ruffles’ heuchera (Heuchera micrantha ‘Chocolate Ruffles’, Zones 3–8). Ligularias are satisfyingly easy to grow. When protected from slug predation and given damp soil and partial shade, ligularias stay lush and full from springtime through frost.

Mayapples (Podophyllum spp., Zones 3–9) have been newly rediscovered by the gardening world and are coveted for their bold, veined foliage splashed and mottled with near-black patterning. This distinctive coloration makes their palmlike, lobed leaves even more dra­matic when planted in a damp, semishaded border or woodland garden where they rise above the soil on tall stems like parasols. The species Podophyllum peltatum (Zones 3–9) spreads to form an 18-inch-tall by 4-foot-wide clump. It has cup-shaped, nine-lobed leaves with waxy, fragrant, pale pink flowers in spring. Podophyllum hexandrum (Zones 5–8), known as the Himalayan mayapple, has broad leaves notably mottled in purplish brown. The leaves of both plants spread to 12 to 14 inches in diameter and look stunning against the fine texture of ferns. Mayapples do best in partial to full shade and thrive in rich, humus soil.

Bold leaves for shady nooks

Brunnera (Brunnera macrophylla and cvs., Zones 3–7), also commonly known as Siberian bugloss, is a small-stature perennial that provides a big punch. While the species sports clean, medium to dark green leaves, there are several variegated selections that are to die for. ‘Jack Frost’ is one of the best and has hit the ground running. Its dinner-plate-size, ovate leaves are so veined and splashed in white that they appear covered in silver. Its tiny, true blue flowers resemble forget-me-nots, and they bloom early to mix with crocuses (Crocus spp. and cvs., Zones 3–8) and daffodils (Narcissus spp. and cvs., Zones 3–9). Like its predecessors, ‘Jack Frost’ prefers shade, where its variegated foliage shows up beautifully. Protect its leaves from slugs, and enjoy it as an edging plant along a woodland border, where it will reach 18 inches tall and 24 inches wide. Unlike many other large-leaved plants, Brunnera species are drought tolerant once established.

Hostas (Hosta cvs., Zones 3–9) are the quintessential foliage perennial. They come in all sorts of shapes, sizes, and colors, several of which fit the bill when a design calls for giant leaves. ‘Sum and Substance’ is one of the biggest and the brightest. It easily forms a 4-foot-wide clump, with each heart-shaped chartreuse leaf spanning 20 inches. It is truly hypnotic as it expands into a wide puddle of sunshine in a shady border, lighting up the garden from spring to frost. Although the leaves steal the show, ‘Sum and Substance’ does send up pale lilac flowers in late summer. For dramatic color contrast, consider placing Hosta ‘Ryan’s Big One’ nearby. It is another giant hosta that forms a 5-foot-wide clump of glaucous, puckered, 18-inch-long leaves and produces white flowers in late spring. As with all hostas, give these big guys moist, fertile, well-drained soil in a spot with partial to full shade and mind any slugs that come along.

Keeping beauty from becoming a beast

Whether you’re beginning a new garden or tweaking an old one, you can add architectural scale and beauty by selecting perennials that grow large. Keep in mind, however, that anything so luxuriant will, of course, outgrow its bounds—no doubt sooner than you intend. Perennials never spread to a certain point and then stop. Nature in its abundant vigor isn’t like that. So be prepared to give over plenty of space to these garden racehorses, or keep your spade and clippers handy to keep them under control.

That’s not to say you should shy away from these plants in small spaces. It’s even more important to vary the scale of the plantings to add depth and intrigue to cramped quarters. Surprisingly, large-leaved plants make small gardens appear larger, in part because they obscure what’s just around the corner.

Petasites japonicus (Zones 5–9), commonly called butterbur or coltsfoot, is a jaw-dropping, 50-mph plant. Its monstrous 32-inch-wide, kidney-shaped leaves cover its huge, 40-inch-tall by 60-inch-wide mounding habit. In early spring, before its leaves arrive, butterbur has stalks topped with tightly clustered, yellow-green flowers. This perennial often needs no companions; it looks good in stands all alone. The variegated form, Petasites japonicus var. giganteus ‘Variegata’, is especially showy, with fragrant flowers and 3-feet-wide, white-edged leaves. Butterbur likes very rich, moist soil in partial to full shade. It’s not for everyone, though; it tends to spread aggressively in wet soil, which may not be a problem if you have a damp, shady spot to fill.

It is said of perennials that in their first year they sleep, in their second they creep, in their third they leap. But most of the plants mentioned here take fewer than three years to show their stuff. Prepare the soil with generous additions of compost, top-dress with a little well-composted manure, water until established, and stand back. These plants will be living large before long, adding architecture and textural variation to your garden.