Umbrella Sedge

Cyperus involucratus, widely sold as Cyperus alternifolius, is the smaller, tougher cousin of papyrus. A clump of erect, triangular stems carries a whorl of narrow, leaf-like bracts at the top that radiate like the spokes of an umbrella, and the true flowers are tiny and insignificant. The RHS gives its native range as Africa and the Arabian Peninsula, and describes it as an evergreen, clump-forming plant of 0.5 to 1 m that takes full sun or partial shade, and as generally pest-free.

It is the easiest water plant for a small pond or a courtyard bowl: stand the pot in 2 to 10 cm of water, or in permanently wet soil, and it grows quickly. Its fine texture is a good foil to the broad, flat pads of Water Lily and the large leaves of Elephant ear. It can tolerate drier sites than most wetland plants, though in Dubai's summer the leaf tips brown quickly if the roots dry out. Because it is evergreen, it keeps the margin of the pond green through Dubai's winter, when many other plants are cut back or resting.

The caution is its spread. It sets seed freely and spreads by short rhizomes, UF/IFAS gives it a 'Caution' rating in Florida, and the Florida Exotic Pest Plant Council lists it as a Category II invasive. In a walled Dubai garden the risk is small, but remove seed heads before they ripen, never tip cuttings or divisions into natural water, and keep it in a pot, since a cut whorl floated on water roots readily.