Sarcococca hookeriana Seeds | Sweet Box
LATIN NAME: Sarcococca hookeriana
COMMON NAME: Sweet Box
Plant Profile
Within the genus this is the big, leafy species. The type variety makes a stiff evergreen shrub up to roughly one and a half metres, with broad, tapered leaves on upright stems, and the lower Himalayan form known as var. digyna is shorter and wider with longer leaves and a habit that spreads by underground stems. From that form came the selection long sold as ‘Humilis’, which stays low, creeps steadily outward and has been planted as ground cover under trees for generations.
The species epithet honours Joseph Dalton Hooker, the Victorian botanist who collected Himalayan plants and later directed the Royal Botanic Gardens at Kew. Sarcococca itself means fleshy berry, which is fair comment on the fruit, and the genus sits in the Buxaceae alongside the boxwoods.
In the wild this plant grows in moist, humus-rich soil under a woodland canopy, and it carries that preference into cultivation. Dry shade is where it suffers, dry sun is where it scorches, and cold wind bronzes the leaves, so a site under a deciduous tree with leaf litter over the roots is close to ideal. It will grow where very little else will, including the north side of a building and the ground beneath mature evergreens.
Use it as the base layer of a shaded planting, beneath the skirts of old trees, where its dark foliage sets off spring bulbs and ferns. Set it beside a path or a door so the winter scent is met at nose height rather than lost in a border. Because it is slow, it is not the plant to fill a gap in a hurry.
Science & Biotechnology
The chemical signature of the box family is a group of steroidal alkaloids built on a pregnane skeleton, and Sarcococca is one of the genera screened for them. The compounds are concentrated in the leaves and berries, they are the reason the plant is unpalatable, and they have drawn attention in cholinesterase research, where steroidal alkaloids of this shape have shown activity.
The shrub propagates easily from semi-ripe cuttings taken with a heel in late summer and rooted in a shaded frame, which is how named forms are kept true. A creeping form such as ‘Humilis’ is quicker from division, lifted in early spring and split with a spade. Seed is slower and variable, so it is for the enthusiast rather than the nurseryman.
Uses & Benefits
The flowers are small and unisexual, clustered in the leaf axils, with several male flowers around a female flower or two at the centre. The male flowers do the show: each has a few broad tepals and prominent anthers, and here those anthers are tinged pink to maroon against the cream of the rest of the flower. The scent is strongest in damp, still air, and on a mild winter day the clusters are worked by early bees, which is the point of producing perfume when nothing else is in bloom.
Pollinated flowers ripen into small, round, glossy black berries in the same axil as the flowers, each carrying one or two seeds. Because male and female flowers sit side by side in the same cluster, a single plant can set fruit on its own. They are not edible: the family’s alkaloid load makes them purgative.
Growing from Seed
Seed carries a dormant embryo and is best sown fresh, as soon as the black berries soften, into a pot of moist, humus-rich compost under a thin layer of grit, kept in a cold frame out of direct sun. Left outdoors, the alternation of cold and mild conditions does the necessary work; do not let the pot dry out.
Once the seedlings have several true leaves and the stems begin to thicken, pot them on individually into a mix of two parts leaf mould, one part garden compost and one part grit, and keep them shaded and moist for their first full season before planting out. Space them about forty centimetres apart for a carpet, or sixty for specimens. Water through dry spells for the first two summers and trim after flowering if the clumps grow lopsided.
Our Take
This is the shrub I reach for when someone tells me the ground under their trees is hopeless, and it usually converts them by the second winter, when they notice where the smell comes from. I plant it with Chinese boxwood for a matched evergreen texture at a different scale, with sweet olive where the autumn scent hands over to the winter one, and against holly so the black berries have something dark behind them. Give it shade and leaf mould and it will outlive the tree it sits under.
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