Tropical pickeral weed

Pontederia rotundifolia syn. Pontederia reniformis

Similar in appearance to the water hyacinth but without the expanded petiole (float)

Common names 
Also known as: Tropical pickeral weed,
Central America And South America
Council declaration 
SIL – Special Investigation List
Known distribution 



The perennials are aquatic plants and prefer a sunny situation. Best suited to substrates with loamy, sandy-loamy or loamy clay soil with a pH between 6,5 and 7,2.


Aquatic herb with a rounded heart shaped leaf aquatic herb, plant attached to the bed of waterways with leaves, stems and flowers emerging. 

Impact and control methods 

A competitive weed of the inland waters and artificial ponds and water masses. It has been listed as a Category 3 invader in South Africa (no further planting is allowed - except with special permission - nor is trade in propagative material. Existing plants must be prevented from spreading).

Stem and leaves 

Annual or perennial. Vegetative stem elongate, floating or on mudflats; Succulent aquatic; stems to 3 m long, prostrateor floating, finally ascending, rooting at lower nodes. Leaves emer­gent
petioles 17-54 cm long (those of the floral leafshoot as short as 5 cm long); petiole sheaths with ligule to 7.5 cmlong (those in axil of floral shoot to 24 cm long); bladesovate-cordate, reniform or sagittate,15-34 cm long, about as wideas long, the sinus open or narrow, the veins closely spaced,radiating from apex of sinus but arcuate-ascending near margin

Flowers and fruits 

Inflorescence with 3-25 flowers; peduncle pilose, 1.4-5 cm long; spathe 1.6-4.5 cm long. Flowers pilose, tube 4-8 mm long, tepals blue or white, 7-12 mm long, the central upper tepal with 2 yellow spots near the center; lower stamens 0.7-8 mm long, upper stamens 6.5-14 mm long, anthers ovoid to oblong, 0.6-1.3 mm long, larger on the longer stamens; ovary 1-2 mm long; tristylous. Nutlet about 7 mm long, including apical attenuate spine.

Reproduction and dispersal 

Predominantly seed, can spread vegetatively from fragmented rhizomes.

Similar species 

Water Hyacinth - E. crassipes is usually a free-floating plant with leaves on or above the water surface. These leaves have a thickened, spongy, stalk (petiole) and a broad leaf blade with entire margins. Its very showy flowers (4-6 cm across) are blue, purplish or mauve in colour (with a yellowish spot).