Cape water lily

Nymphaea caerulea ssp. zanzibarensis
Aquatic
Alternate
Simple
Pink
Purple
Blue
Green
Common names 
Also known as: blue Egyptian lotus, blue lotus, blue waterlily, Cape blue waterlily, Cape water lily, Egyptian lotus, royal purple waterlily,
Family 
Nymphaeaceae
Deciduous 
No
Flowering time 
Summer and Autumn
Native/Exotic 
Exotic
Origin 
Native to north-eastern, eastern and southern Africa
Notifiable 
No
State declaration 
Nil
Council declaration 
Class R – Reduce populations
Known distribution 

Widely naturalised in the coastal districts of eastern Australia (i.e. in south-eastern and central Queensland and in northern and central New South Wales).

Habit 

Cape waterlilly is an emergent, perenial aquatic plant that has round floating leaf blades with irregular toothed margins and blue to purple flowers with pointed petal tips. The flowere are emergent and held above the water's surface.

Impact and control methods 

Cape blue waterlily (Nymphaea caerulea) is regarded as an environmental weed in Queensland and New South Wales. This widely grown aquatic plant has escaped cultivation and become a weed of freshwater habitats (i.e. dams, ponds, lakes, lagoons, wetlands, and slow-moving waterways), where it displaces similar native species.

Stem and leaves 

Leaves circular with a radial slit, 30–40 cm diam., margins irregularly toothed.

Flowers and fruits 

Flowers emergent, to 15 cm diam., standing c. 30 cm above the water surface. Sepals 4, green with the margins white or with a bluish tint; the green areas of the sepals may be flecked with very dark blue spots, especially in cultivated forms. Outer stamens petaloid; appendage larger on outer stamens, small on inner stamens, the same colour as the petals. Ovary globose; lobes short with stigmatic surface on lower 50–60%. Its flower can vary in colour from blue to pink. Caerulea means ‘blue’. 

Similar species 

It can be confused with a couple of other species...Nymphaea gigantea , which is native, but is now considered to be almost extinct in S E Qld.

Nymphaea violacea is a beautiful water lily with a pinkish/blue flower.  It has a wavy margin to the leaf, rather than toothed or serrate. It grows in North Queensland, NT, and W A. Flower is on a long [up to 30 cm] stalk. It also lacks the blue terminal anther of Nymphaea caerulea subsp.Zanzibarensis.