Delphiniums are renowned for their towering, majestic spires that command attention in the garden. To complement this vertical drama, plants with contrasting forms create a harmonious and dynamic border. Ornamental grasses, such as Fountain Grass (Pennisetum alopecuroides) or Feather Reed Grass (Calamagrostis x acutiflora 'Karl Foerster'), provide an excellent textural counterpoint. Their fine, arching foliage and soft, feathery plumes sway gracefully in the breeze, softening the rigid uprightness of the delphinium spikes. This combination of bold verticals and soft, flowing mounds establishes a strong architectural foundation for the planting scheme.
The large, deeply lobed, palmate leaves of the delphinium offer a wonderful opportunity for foliage play. Pairing them with plants that have distinctly different leaf shapes, textures, and even colors enhances the visual appeal of the garden bed even when flowers are not in bloom. The broad, heart-shaped, often silver-veined leaves of Lady’s Mantle (Alchemilla mollis) catch dewdrops beautifully at the delphinium's base. Similarly, the silvery, furry foliage of Lamb's Ear (Stachys byzantina) creates a stunning tactile and visual contrast. For a bold color contrast, consider planting with Heuchera (Coral Bells), which offers a palette of foliage in shades of plum, lime, bronze, and deep burgundy right at the delphinium's feet.
While delphiniums provide a spectacular show in early to mid-summer, their bloom period can be relatively brief, especially after the main flower spike fades. Strategic companion planting ensures a succession of color. Planting early summer bloomers like hardy Geraniums (Cranesbill) or Nepeta (Catmint) around them provides color before and after the delphinium's performance. Following the delphinium's lead, mid to late-summer blooming perennials like Phlox paniculata, Monarda (Bee Balm), or Echinacea (Coneflower) can take over the floral display. These plants help to fill the space and maintain interest, effectively camouflaging the delphinium's foliage, which can sometimes look tired after flowering.
The most successful plant partnerships are those that share similar cultural needs. Delphiniums thrive in full sun and require rich, fertile, well-drained soil that is kept consistently moist. They are not drought-tolerant. Therefore, choosing companions that enjoy these same conditions is crucial for the health of the entire planting. Roses, particularly English-style shrub roses, are classic partners, enjoying the same rich soil and sun. Other excellent choices include tall-growing Campanula persicifolia (Peach-leaved Bellflower), which echoes the delphinium's spire form in a different hue, and Achillea (Yarrow), which provides flat-topped flower clusters that attract beneficial pollinators, creating a lively and ecologically supportive garden environment.
