Bauhinia purpurea Seeds | Hong Kong Orchid Tree Magenta
.jpg "Orchid Tree (Bauhinia purpurea) seed")
LATIN NAME: Bauhinia purpurea
COMMON NAME: Orchid Tree
Plant Profile
Bauhinia purpurea announces itself with a leaf as strange as its bloom: each leaf is split halfway down the middle into two rounded lobes, so it looks like a butterfly that folded its wings, and the flowers answer with five magenta petals veined in a deeper purple. On a warm street the tree throws these orchid-like blooms in waves through the season, which is why it is planted from Mumbai avenues to Hong Kong gardens. The bilobed leaf alone is enough to name the plant from a glance.
After the flowers fade, Bauhinia purpurea sets long, slender, flattened pods that hang like beans and spill round seeds, true to its pea-family kin. Its celebrated relative Bauhinia blakeana, the Hong Kong flower, is a near-twin in magenta but carries no pods at all because it is sterile, which is why the purple species, not the emblem, is the one that breeds from seed. The two are easy to mix up until you look for the pod.
Planted as a street or courtyard tree, B. purpurea gives a long season of magenta colour and a light, scented shade that suits warm cities. A few cut branches hold their flowers for a long while in water, and the tree tolerates clipping into a multistem specimen. In a warm climate the tree flowers on and off through much of the year, so a single specimen supplies cut blooms for months on end, and the light canopy lets shade-lovers grow beneath it. In colder climates it is a conservatory or patio plant that spends summer outdoors and winter under cover.
Science & Biotechnology
The bark and pods of B. purpurea carry tannins and a spread of flavonoids that account for its long place in traditional preparations across south Asia, while the flowers hold anthocyanins that give the petal its purple. Extract studies have used warm water and ethanol to pull those fractions from bark and leaf, the same gentle solvents that suit a home tisane. The seed oil and the pod fibre are minor by-products rather than crops.
Because the showy B. blakeana cannot set seed, breeders cross it with fertile relatives like purpurea to recover pod-bearing offspring with bigger blooms, a small but steady line of horticultural work. Clonal forms are held by grafting onto a purpurea rootstock, which is why a named orchid tree in a garden is usually a graft. The species itself grows readily from the seed it freely drops.
Uses & Benefits
The leaf is the key field mark, a single blade cleft into two lobes from the tip almost to the base, sometimes called ox-hoof shaped. The flower carries five unequal petals, the uppermost broadest and marked with darker veins, and it is faintly fragrant, strongest toward evening when moth pollinators are about. The bloom is bisexual and opens on wood from the previous season, so a hard prune costs the next show.
Beyond the street, the bilobed leaf is a favourite motif in local art and the bark features in traditional recipes, so the tree is cultural as well as decorative. These uses are why it was carried around the tropics as a collected ornamental long before any breeding programme touched it.
Growing from Seed
Nick the hard seed coat or soak it in warm water until it swells, then sow it in a free-draining sandy loam and cover it lightly. Keep the medium warm and just moist; the seedling lifts its first bilobed leaf as soon as it roots, which makes the young plant easy to spot. Pot it on when the second true leaf has opened and grow it warm.
Set the tree in full sun and well-drained soil in a frost-free district, spacing plants four to five metres apart for an avenue. Water it in well and mulch the base, but back off once it establishes because the pea family dislikes wet feet. For warm-climate companions, the Bauhinia variegata, the Hong Kong orchid tree (Bauhinia blakeana), the redbud (Cercis canadensis), and the Chinese wisteria (Wisteria sinensis) share the showy-bloom brief.
Our Take
Bauhinia purpurea is the orchid tree that actually breeds, so grow it from the pod you collect and you will have a street of magenta for the price of one, provided you keep it warm and never prune the wood that carries next year’s bloom.
Related Reading
More species in the same orbit as Orchid Tree: