Cyperus articulatus Seeds | Jointed Flatsedge
LATIN NAME: Cyperus articulatus
COMMON NAME: Jointed Flatsedge
Plant Profile
Jointed flatsedge is a tall, leafless sedge of tropical swamps, and its aromatic rhizome is the source of an oil used in perfume. It grows in shallow water and wet mud along rivers, lakes and floodplains throughout the tropics, from West Africa and the Nile to India, Southeast Asia and the Amazon, and it is often the dominant plant at the water’s edge. The culms rise one to two metres, are round, pithy and marked at intervals by dark bands where the internal tissue has broken down, which is what the name articulatus refers to. There are almost no leaves: the plant photosynthesises through the green stems, and the flowers sit in a loose, branched head at the top. The rhizome runs horizontally through the mud, is covered in overlapping scales and smells strongly of spice when cut. It is the part that is harvested, and the part that carries the plant from one bank to the next.
Science & Biotechnology
Cyperus articulatus spreads mainly by its rhizome, which branches and fragments and can be carried downstream to root on a new mud bank; seed is produced in quantity but seedlings are rarely seen in the wild. The jointed culms contain large air spaces at the nodes, which keep the plant upright in soft mud and allow oxygen to move down to the roots. The essential oil of the rhizome is unusual in being dominated by sesquiterpenes, principally cyperone and mustakone, rather than by the monoterpenes common in aromatic grasses, and it is this chemistry that gives the oil its warm, woody, slightly camphoraceous scent. In the Amazon the species is known as priprioca, and the oil has become a fixture of Brazilian cosmetics, harvested from cultivated stands rather than wild ones. The plant also sets a dense network of fine roots that trap sediment, which is why it stabilises banks and why it can choke irrigation channels.
Uses & Benefits
The rhizome is distilled for an oil used in perfumery, where it acts as a fixative and lends a soft, earthy note to woody and oriental compositions; Brazilian firms have built a small industry around it with riverside communities. In West Africa and India the rhizome is used in medicine for stomach pain, fever and convulsions, and it is burned as a fumigant against insects. The culms are woven into mats, baskets and chair seats, and they are used as thatch and as a mulch. In parts of Africa the plant is planted along fish ponds and channels to hold the bank, though it can become a nuisance where flow is slow. For gardeners in warm climates it makes a bold, architectural plant for a bog garden or the edge of a pond, with a scent that carries on a still evening. It is too vigorous for a small water feature and it will walk out of its basket within a season.
Growing from Seed
Seed is rarely available and slow to handle; the practical route is division of the rhizome in spring, cut into sections with two or three growing points and potted into wet loam. Keep the pots standing in two centimetres of water and in full sun, and the new culms will appear within a month. Plant out into a bog garden or a submerged basket once the water has warmed, setting the rhizome just below the mud surface. In cold climates grow it in a container that can be lifted before frost, since the plant is killed below about minus two. Feed sparingly: rich water produces tall soft culms that fall over. Cut old stems to the base in spring to make room for new growth, and divide the clump every third year to keep it in bounds. Harvest rhizomes for oil in autumn, when the aroma is strongest.
Our Take
A tall jointed sedge with a rhizome that smells of warm wood and spice. Grow it in a bog, in full sun, and keep it contained.
Related Reading
More species in the same orbit as Jointed Flatsedge: