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Scientific: Cyperus involucratus (Synonyms: Cyperus alternifolius, Cyperus flabelliformis, Cyperus gradatus, Cyperus petersianus, Cyperus proximus)
Common: umbrella plant, umbrella flatsedge
Family: Cyperaceae
Origin: Madagascar

Pronounciation: SIGH-PER-us in-vol-u-CRA-tus

Hardiness zones
Sunset
8-9, 12-24
USDA 8 (freezes to ground in winter but recovers quickly in spring)-11

Landscape Use: Mesic landscape design themes around pools, ponds, water features, dry washes, tropical settings, containers, needs root restriction to limit spreading

Form & Character: Herbaceous perennial, upright and stiff with umbrella top, marsh plant suggests water.

Growth Habit: Upright and clumping to 3 feet in height.

Foliage/Texture: Stems, green, obtusely triangular to rounded, finely striate, leaves nothing more than a reddish brown sheaths at the base of stems. At the terminus of each stem is a whorled arrangement of elongated, nearly linear "leaves" (actually bracts); medium fine texture.

Flowers & Fruits: Inflorescence is a compound umbel with short raylet spikes emanating above whorled bracts, immature flowers yellow-green maturing to brownish yellow. Fruits are a small dull brown achene.

Seasonal Color: None

Temperature: Shoots can be damaged by freezing temperatures during winter (if that ever happens again in Phoenix, no thanks to the urban heat island effect), but plants recover quickly when the weather warms in early spring.

Light: Perfers partial, filtered shade.

Soil: Tolerant of, in fact prefers damp to wet soil.

Watering: Regular supplental water required in Phoenix with frequencies being higher in summer and lesser in winter.

Pruning: Shear close to the ground every 2 years to rejuvenate and to remove build up of thatch.

Propagation: Division of root clumps.

Disease and Pests: None

Additional comments: This is a great plant to use around ponds, pools, or fountains or to suggest or enhance the presence of water in the landscape. The cultivated variety 'Gracilis' (dwarf umbrella plant) is smaller, more fine textured, and rarely flowers.

Naturalized alert: Umbrella plant has widely naturalized in tropical areas and has been cultivated for over 2,000 years. In a landscape setting umbrella plant needs soil containment, lest it will spread like crazy.