Both 'The Pearl' and the standard 'Single' variety belong to the species Polianthes tuberosa, a member of the Asparagaceae family. They are herbaceous perennial plants, prized exclusively for their extraordinarily fragrant flowers. Originating from Mexico, they thrive in warm climates and are typically grown as tender bulbs (more accurately, rhizomatous tubers) in the US, often lifted and stored over winter in colder zones. Both varieties share a requirement for full sun, well-draining soil, and a long, warm growing season to initiate their spectacular bloom period, which occurs from mid-summer to fall.
The most significant distinction between the two varieties lies in their flower morphology and inflorescence architecture. The 'Single' variety produces the classic tuberose flower structure. Its flowering spike is composed of numerous fragrant, waxy-white flowers arranged in a raceme. Each individual flower is single, characterized by a tubular corolla that opens into six distinct, flaring lobes. This is the traditional form and the one most commonly used in the perfume industry for essential oil extraction due to its potent fragrance output.
In contrast, 'The Pearl' is a double-flowered cultivar. Its blooms are far more complex and ornate. The double flowers are created through a process of petalody, where the reproductive stamens are transformed into additional petal-like structures. This results in a densely packed, rosette-like flower head with many layers of petals, giving it a fuller, more voluptuous appearance reminiscent of a gardenia or a double camellia. The flower spike itself may be slightly shorter but is often just as robust.
While their overall growth habit is similar—forming a basal clump of grass-like leaves—the two varieties differ in their vigor and reproductive strategy. The 'Single' tuberose is generally considered more vigorous and a faster multiplier. The mother tuber easily produces offsets (daughter tubers) around its base, which can be separated and replanted to propagate new, genetically identical plants. This makes it a reliable and economical choice for gardeners.
'The Pearl', with its highly modified and sterile double flowers, invests more energy into floral display than into reproduction. It is a much slower and less prolific multiplier, producing very few, if any, viable offsets. Consequently, 'The Pearl' is more expensive and less commonly available, as its propagation is more challenging and reliant on tissue culture or careful division of the main tuber to maintain the double-flowering trait.
The sensory experience offered by each variety is notably different. The 'Single' variety is renowned for its intensely sweet, heady, and complex scent, which is most potent in the evening and night. Its fragrance is the quintessential tuberose aroma—powerful, creamy, and exotic. Aesthetically, it offers a more elegant and streamlined look.
'The Pearl' provides a slightly altered olfactory experience. Its scent is often described as equally sweet but perhaps slightly less intense and more complex due to the density of its floral parts. Visually, it is the more dramatic of the two, with its opulent, double blooms creating a stunning visual impact in the garden and in cut flower arrangements, where each flower stem serves as a full and luxurious focal point.
