Some like it damp
While some of you may regard a reliably soggy, slow-draining spot in your garden with dismay, I look on it as an opportunity to grow plants that don’t reach their full potential in the drier, well-drained conditions found in most herbaceous borders. And there’s no need to abandon petals either; a huge palette of flowering plants is ready and waiting to go. Fancy-leaved hostas and ferns will always be useful in moist shade, as will ornamental grasses like Miscanthus in poorly drained sunny spots, but I like to stack the deck with perennials that provide a steady succession of blooms, as well as attractive foliage and contrasting leaf colours and textures.
Many of us have areas in our gardens that are low-lying — where water collects after snow melts in the spring and after heavy rainfalls during the growing season. Some plants prefer these extra-moist conditions, and even tolerate a few inches of standing water around their crowns for a few days. These perennials can also add colour and drama to the edges of ponds and streams, but they are not aquatics, and do require a drying-out period between dousings. So forget about weeping tiles and raised beds, and instead of fighting Mother Nature (she’ll always have the last word anyway), choose perennials that will thank you for your soggy soil.
Plants for soggy soil and shade
Most of these perennials happily tolerate a few hours of morning sun, but they must be protected from scorching afternoon rays.
1. Cimicifuga cultivars (Actaea simplex [Atropurpurea Group] cultivars)
Once an expensive brag plant, cimicifuga is now widely available at reasonable prices. Native from Russia to Japan and hardy to Zone 4, purple-leaved cultivars such as ‘Brunette’, ‘Hillside Black Beauty’ and ‘Black Negligee’ are worth their weight in gold. Plants grow 12 to 30 inches (30 to 75 cm) tall. Lacy, purple-black leaves emerge in mid-spring followed by eight-inch (20-cm) racemes of white- to cream-coloured, grape bubblegum-scented flowers in early autumn.
2. Jack-in-the-pulpit (Arisaema triphyllum)
Every kid’s favourite woodland plant, Jack-in-the-pulpit is a tuberous perennial that produces one or two leaves that are each divided into a further three leaflets. In spring, four- to six-inch (10- to 15-cm) hooded green spathes emerge, often with dark purple stripes, followed by clusters of bright red berries in fall. Also known as bloody arum, this distinctive flower is native to eastern North America and hardy to Zone 4.
3. Mourning widow (Geranium phaeum)
I was turned on to this terrific species by hardy geranium expert Trevor Bath of England (who introduced the cultivar G. p. ‘Lily Lovell’) and I’ve never been without it since. Mid-green leaves with purplish brown or black splotches give rise to 30-inch (75-cm)-long branched cymes bearing purplish-black flowers with white centres (there are also white and mauve cultivars). Native from central Europe to Russia and hardy to Zone 4, plants self-seed where they find conditions to their liking. Plants bloom in early summer; cut back after flowering and fertilize (e.g., 15-30-15) for a second set of blossoms in late summer.
4. Yellow wax-bells (Kirengeshoma palmata)
An underutilized perennial, it produces two- to four-foot (60- to 120-cm)-tall purple stems bearing handsome mid-green, palmate leaves. In late summer and early fall, nodding cymes of three pale yellow flowers appear, 1½ inches (4 cm) long, which are often likened to small shuttlecocks. Native to Japan and hardy to Zone 5, mature specimens grow to 30 inches (75 cm) wide.
5. May apple (Podophyllum peltatum)
I like this wonderfully architectural plant so well that I have a large patch of it growing beside my north-facing front door. Native to eastern North America and hardy to Zone 4, it produces umbrella-like leaves up to 12 inches (30 cm) long on 12- to 18-inch (30- to 45-cm)-tall stems. In mid-spring, fragrant, two-inch (5-cm)-wide, solitary white to pink flowers are produced under the foliage, followed by an edible yellowish-green fruit.
6. Common primrose (Primula vulgaris and cultivars)
While I prefer the straight species form of the common primrose, any of the multicoloured plants you buy at the supermarket will do well in consistently moist conditions (pale yellow-flowered varieties seem to be the hardiest), as will the lovely cowslip (P. veris). This genus of spring-flowering perennials is native to Eurasia and hardy to Zone 4; mature clumps grow five inches (13 cm) tall by six inches (15 cm) wide.
7. Fringe cups (Tellima grandiflora)
Somehow lost in the shuffle between Heuchera, Tiarella and their progeny, ×Heucherella, is Tellima, native to western North America and hardy to Zone 4. Often recommended as being “drought tolerant,” fringe cups performs best in consistently moist soil. Handsome two- to four-inch (5- to 10-cm)-long leaves may be triangular, heart- or kidney-shaped, and are usually lobed and scalloped. From late spring to midsummer, 12-inch (30-cm)-tall racemes of white to pale green flowers appear; some strains are fragrant.
8. Merrybells (Uvularia grandiflora)
Native to eastern North America and hardy to Zone 3, this is another woefully underused perennial that blooms in spring. Spreading slowly by rhizomes, merrybells bears five-inch (13-cm)-long mid-green leaves that point downward, followed by distinctive, two-inch (5-cm)-long yellow flowers with slightly twisted petals.
Plants for soggy soil and sun
While many of these perennials will tolerate partial shade, they grow more robustly in full sun.
9. ‘Arendsii’ monkshood (Aconitum carmichaelii [Arendsii Group] ‘Arendsii’)
This is an older cultivar and garden stalwart of substantial proportions; established clumps measure five to six feet (1.5 to 1.8 m) tall by 16 inches (40 cm) wide. In spring, five-lobed, shiny, dark green leaves emerge, giving rise to hooded, deep blue to violet flowers on one- to two-foot (30- to 60-cm)-long branched panicles in early autumn. Native from Russia to China and hardy to Zone 3, ‘Arendsii’ is usually the last perennial to bloom in my garden.
10. ‘Robustissima’ Japanese anemone (Anemone xhybrida ‘Robustissima’)
This wonderful perennial hitch-hiked its way to my garden in a clump of bloodroot, and from a tiny slip, I now have a thriving clump. It’s a complicated hybrid of mostly Chinese origin and hardy to Zone 4. In spring, mid-green, palmate foliage appears, followed in late summer or early autumn by long-lasting, pale-pink flowers, two to three inches (5 to 8 cm) across. Mature plants grow three feet (1 m) tall by two feet (60 cm) wide.
11. Masterwort (Astrantia major)
Masterwort has become more popular thanks to a number of exceptional new cultivars that sport 1¼-inch (3-cm)-wide, reliably dark red flowers (e.g., ‘Moulin Rouge’ and ‘Ruby Wedding’). Native to central and eastern Europe and hardy to Zone 4, plants have deeply lobed, toothed leaves that emerge in spring, followed by umbels of elegant, papery bracts that vary in colour from white or pale green to pink and purple-red in summer. Although I usually approach variegated plants with caution, A. m. ‘Sunningdale Variegated’ is a great favourite.
12. Pink turtlehead (Chelone lyonii)
Once you observe the blooms of turtlehead, it comes as no surprise to learn that it’s a member of the snapdragon family. Native to North America and hardy to Zone 3, turtlehead has erect, three- to four-foot (1- to 1.2-m)-tall, square-shaped stems bearing racemes of one-inch (2.5-cm)-long deep pink flowers with yellow beards. Blooms from late summer to mid-autumn. C. obliqua is a smaller species with purple flowers; C. glabra is medium-sized and has white blooms.
13. Fragrant hosta (Hosta plantaginea)
Despite its plain green leaves, this is my favourite hosta. Demanding a sunny location, in late summer and early autumn, 24- to 36-inch (60- to 75-cm)-tall leafy green scapes bear four-inch (10-cm)-long, wonderfully fragrant, pristine white trumpets. It’s native to China and hardy to Zone 3. The double-flowered cultivar ‘Aphrodite’ is often easier to find at garden centres.
14. ‘The Rocket’ ligularia (Ligularia ‘The Rocket’)
A cross between two Chinese species (L. przewalskii x L. stenocephala) and hardy to Zone 4, ‘The Rocket’ emerges in spring with toothed, triangular mid-green leaves on strong black stems. By mid- to late summer, flowering spikes reach four to six feet (1.2 to 1.8 m), bearing dense racemes of 1½-inch (4-cm)-wide, bright yellow flowers.
15. Cardinal flower (Lobelia cardinalis)
Although a short-lived perennial, lobelia self-seeds in ideal conditions, and its short rhizomes will spread cautiously. In spring, overwintering rosettes of four-inch (10-cm)-long bronze-green leaves begin to re-sprout, and from summer to early autumn 14-inch (35-cm)-long stems bearing racemes of brilliant scarlet-red flowers appear. Native to eastern North America and hardy to Zone 3, more than two dozen hybrids have been introduced, including the classic ‘Queen Victoria’.
16. Rodgersia (Rodgersia pinnata)
A consummate architectural plant, large, heavily veined and crinkled foliage that resembles chestnut leaves emerges in late spring from vigorous rhizomes. From mid- to late summer, strong three- to four-foot (1- to 1.2-m)-tall stems bear large, showy panicles of small white, pink or red flowers. Native to China and hardy to Zone 4, many excellent new cultivars have been introduced in the past decade.
The best times to plant perennials are from mid-spring to early summer and in early autumn. Amend planting holes with plenty of organic matter, such as compost or composted manure.