Seasonal Wild Flowers

Latin name

Pontederia cordata

Other names

Pontederia, Pickerel Weed

Family

Pontederiaceae

Flowering season

June to September

English distribution

It is scattered through most of the country but is most

common in southern regions and absent the far North.

For a map see the Botanical Society of Britain and Ireland –

Pickerelweed

Habitat

It is a neophyte introduced from North America in the mid

1800s and grown in the UK as an ornamental plant in

ponds. It has escaped into the wild and recorded as

naturalised since the late 1940s. Since then it has been

spreading. It is robust and can grow in dense stands with

the potential to be invasive but it is not yet clear that it is.

Indeed it has been given an RHS award for garden merit. 

However, Plantlife suggests it should be treated as an

alien invasive plant in the UK..

Description

Pickerelweed is a rhizomatous, semi-submerged herb

which grows up to 120cm at the margins of ponds and

other still waters.

The flowers are in dense spikes up to 15cm long.

Individual flowers are up to 1cm across and made up

of 6 different sized violet-blue tepals joined at the base.

There are 6 stamens and a single long style with a

capitate stigma.

They have yellow nectary guides which are thought to

attract pollinators.

Fruits are dry with 1 seed.

Leaves are green, triangular to ovate, cordate at the

base and up to 25cm.

They have long petioles.

Pontederia cordata Alba is a white-flowered variety..