Both Belladonna and Elatum delphiniums belong to the genus Delphinium within the Ranunculaceae (buttercup) family. They are herbaceous perennials, meaning they die back to their root systems each winter and regrow from the crown each spring. Despite their shared genus, they represent two distinct hybrid groups with different ancestral backgrounds. The primary distinction lies in their genetic heritage, which directly influences their morphology, growth habit, and preferred use in the garden.
The Elatum Group hybrids are derived primarily from Delphinium elatum, a tall, robust species native to mountainous regions of Europe and Asia. This ancestry is the key determinant of their characteristic form. Elatum hybrids are celebrated for their immense, densely-packed flower spikes, which are complex compound racemes. Each individual flower (floret) is semi-double to double, often featuring a central cluster of smaller petals called the "bee" (a staminode petaloid). They are true giants of the perennial border, typically reaching heights of 1.5 to 2.1 meters (5 to 7 feet) and requiring staking to support their heavy, magnificent inflorescences. The flowering stem is solid and strong, emerging from a central clump of deeply lobed, palmate leaves.
In contrast, the Belladonna Group hybrids originate from a cross between D. elatum and D. grandiflorum (a lower, more branching species). This mixed heritage results in a fundamentally different growth habit. Belladonna delphiniums are characterized by their more loose, branching, and graceful form. Instead of a single, massive spike, they produce numerous panicles or sprays of flowers on well-branched stems. The florets are typically single or semi-double, giving them a lighter, airier appearance compared to the dense opulence of the Elatums. Their overall stature is shorter and more bushy, generally growing between 0.9 to 1.2 meters (3 to 4 feet) tall, and they often possess a slightly more relaxed, self-supporting habit.
The differing morphologies of these two groups lead to distinct horticultural applications and requirements. Elatum hybrids, with their towering spikes, are quintessential "thriller" plants for the back of a traditional border, providing dramatic vertical accent and a formal structure. Their cultivation is more demanding; they require rich, fertile soil, consistent moisture, and shelter from strong winds. They are also generally less heat-tolerant and have a shorter lifespan, often treated as short-lived perennials.
Belladonna hybrids, with their branching habit and multiple flowering stems, integrate more easily into mixed borders and cottage garden schemes. They provide a softer, more naturalistic effect and are generally easier to grow. They tend to be more tolerant of a wider range of conditions, are slightly more heat-resistant, and are often longer-lived and more robust perennials. A key botanical identifier is that Belladonna types frequently produce lateral flowering shoots (branching) from the main stem, whereas Elatums primarily produce a single, dominant central spike.
