April is a pivotal month for gardeners looking to extend their garden's bloom cycle well into the warm season. While many associate bulb planting with spring or fall, a range of summer-flowering bulbs and tubers can be started now, ensuring a sequence of color from late spring through autumn. This guide highlights eight such plants, each with specific growing needs and ornamental value.
Before planting, it's essential to prepare the soil. Most of these plants thrive in semi-moist, well-draining soil enriched with organic matter. For heavy soils, incorporating agricultural sand, grit, or perlite can improve drainage. Containers should use a high-quality potting mix or a specialized bulb mix. With these basics in mind, here are eight standout choices for a summer display.
Dahlia 'Cornel Bronze'
For those who appreciate ball dahlias but prefer a more compact stature, 'Cornel Bronze' offers copper-bronze blooms with tightly curled petals. This dahlia grows to 3-4 feet tall and thrives in full sun, suited for hardiness zones 8-11. Although often grouped with bulbs, dahlias grow from tubers. In cooler regions, tubers should be dug up in fall and stored over winter, then replanted in spring.
Red Hot Poker 'Alcazar'
Kniphofia 'Alcazar', commonly known as red hot poker, produces striking red-orange, tubular flowers on tall spikes, reaching 3-4 feet. It prefers full sun and well-draining, sandy soil, and is hardy in zones 6-9. These plants attract hummingbirds, butterflies, and bees. While not true bulbs, they are often sold as bare-root rhizomes; soaking the roots for an hour before planting can help establishment.
Oriental Lily Mix
A blend of oriental lilies (Lilium spp.) provides a spectrum of whites, reds, pinks, and fuchsias in mid-summer. These lilies grow 2-4 feet tall, tolerate full sun to partial shade, and are hardy in zones 3-9, making them suitable for most of the continent. They are excellent for cutting gardens but are extremely toxic to cats and rabbits. Regular division keeps them blooming year after year.
Ranunculus 'Ready for Romance'
Although late winter is often recommended, April is a viable time to plant ranunculus (Ranunculus asiaticus) in regions with cooler summers. This blend offers deep pink, white, and pale pink, densely petaled blooms on 1-2 foot plants, thriving in full sun and hardy in zones 8-10. In areas with hot summers, tubers should be dug up in early fall and stored over winter. They are excellent for cutting gardens and cottage borders.
Calla Lily 'Vermeer'
Distinct from the classic white calla, 'Vermeer' features a rich purple throat surrounded by speckled green foliage. This tropical plant grows 1-2 feet tall, prefers full sun to partial shade, and is hardy in zones 8-10. Its blooms last one to two weeks in a vase, making it a superb cut flower. Its compact size allows for container gardening or small raised beds.
Louisiana Iris 'Black Gamecock'
For gardeners with consistently moist or even boggy areas, Iris 'Black Gamecock' is a standout. This North American native, a cross of multiple Louisiana iris species, grows 2-3 feet tall and blooms from early to mid-summer. It tolerates full sun to partial shade and is hardy in zones 4-9. Plant rhizomes just below the soil surface, shallower than typical bulbs. It can even be grown in a container water feature.
Non-Stop® Begonia
Tuberous begonias from the Non-Stop® series bring rose-like blooms in red, yellow, pink, and white from mid-summer through fall. They grow 8-12 inches tall, prefer partial to full shade, and need moist but well-drained soil. Hardy in zones 10-11, they are often treated as annuals in cooler climates. They make excellent focal points in shady borders or woodland edges, though their vase life is minimal.
Planting these summer bloomers in April sets the stage for a garden that remains vibrant well beyond the spring season. Each species offers unique colors and forms, and with proper attention to soil, sun, and hardiness zones, gardeners can enjoy a succession of blooms that carry the landscape through the hottest months.
