Fill Gaps with Foliage
Foliage plants offer a fine contrast for other garden plants. Constant favorites for bog and pond gardens are the various elephant ears (Colocasia esculenta), which range in color from deep green to near-black. 'Mojito', for example, combines dark purple freckles and flecks on rich medium green leaves. Other favorites include deep purple 'Black Magic' and the unusual 'Coffee Cups', which forms 6-foot-tall clumps of deeply cupped olive green leaves. All do best in the shade, and most will overwinter in Zones 7 to 11. In colder climates, bring the plants indoors for the winter, or mulch heavily. When purchasing, look for large, fresh bulbs, as these will reliably produce the best foliage.
Accent with Flowers
North American bog gardeners are lucky to have numerous hardy and attractive natives to choose from. Deep red cardinal flower (Lobelia cardinalis), for example, is nearly indestructible (and quite rampageous). It is a hardy perennial (Zones 2 to 8) that thrives in sun to shade and blooms from late summer through fall. Swamp milkweed (Asclepias incarnata)–hardy in Zones 3 to 9–has summer-blooming pink flowers that hummingbirds and butterflies can't resist.
Finish with Groundcovers
Low-growing plants prevent erosion, hide mud, and preserve soil moisture for other bog plants. Many groundcovers also produce masses of flowers. Moneywort (Bacopa mon-nieri) spreads across boggy soil and shallow water, and is almost constantly covered in white flowers with pink and blue accents. Native moneywort handles light foot traffic and thrives in sun or shade. Hardy in Zones 6 to 10.