Mentha aquatica - Water Mint, Native Pond Marginal Plant

Mentha aquatica, known as water mint, is a UK native marginal plant with strongly aromatic, dark green leaves on reddish stems. From July into September it carries rounded clusters of lilac-pink flowers that are very popular with bees and butterflies.

Water mint at a glance

Botanical name	Mentha aquatica
Common name	Water mint
Plant type	Spreading perennial; dies back in winter
Height and spread	Usually up to 50 cm tall (RHS: occasionally to 90 cm), spreading 50–100 cm
Flowers	Lilac-pink, in rounded clusters, July to September
Position	Full sun or part shade (best flowering in sun)
Soil	Wet mud or shallow water
Pond depth	0–10 cm of water over the crown
Hardiness	RHS H6 – hardy in a very cold winter (-20 to -15°C)
Native to	UK and Ireland (native wild flower)

Where to plant water mint

The shallow edge of a wildlife pond, 0–10 cm deep
Muddy margins of larger ponds and streams
A planting basket, to keep it in check in smaller ponds

Is water mint good for wildlife?

Yes. It is on the RHS Plants for Pollinators list. The Wildlife Trusts record small tortoiseshell, peacock and comma butterflies visiting the flowers.

Does water mint spread?

Yes, quickly. It spreads by runners and can take over a small pond if left loose. Grow it in an aquatic basket and trim runners that escape over the rim.

How to plant and care for it

Plant in spring with no more than 10 cm of water over the crown. Do not let the basket dry out, as dry plants are prone to mildew and mint rust. Cut back old stems in autumn.

Is water mint edible?

Water mint is a culinary herb and the leaves have been used like other mints, but do not eat leaves picked from a pond or from the wild.

Which size should I buy?

Bare-root plants (7 cm, 9 cm, 1 litre and 3 litre) arrive without a pot or compost and are the most economical way to plant a group. Potted plants (9 cm, 1 litre and 3 litre) arrive growing in our peat-free compost and give a faster display. Packs of 3 come in 7 cm, 9 cm, 1 litre and 3 litre bare-root sizes and cost less per plant. The 2x Pot & Compost option is two plants supplied with pots and compost.