Mimulus guttatus - Monkey Flower, Pond Marginal Plant

Mimulus guttatus (now listed as Erythranthe guttata), known as monkey flower, is a short-lived, mat-forming perennial with toothed, oval, mid-green leaves on hollow stems. In summer it carries bright yellow, trumpet-shaped flowers, often spotted red or reddish-brown in the throat.

Monkey flower at a glance

Botanical name	Erythranthe guttata (syn. Mimulus guttatus)
Common name	Monkey flower
Plant type	Short-lived, mat-forming perennial; dies back in winter
Height and spread	About 30 cm to 1 m tall (sources differ), 50–100 cm wide
Flowers	Bright yellow trumpets, often spotted red in the throat, July to September
Position	Full sun or part shade
Soil	Permanently moist, fertile, humus-rich soil or wet mud
Pond depth	Wet mud at the pond edge; no source gives a water depth
Hardiness	RHS H5 – hardy in a cold winter (-15 to -10°C)
Native to	Not UK native; naturalised along UK streams and ponds

Where to plant monkey flower

Wet mud at the edge of a garden pond
Bog gardens with permanently moist, fertile soil
Full sun or part shade

Does monkey flower spread?

Yes. It spreads by seed and by stems that root into wet mud, and it has escaped along streams, rivers and ponds in the UK. It is not legally restricted, but keep it to garden ponds and do not plant it beside natural watercourses.

How to plant and care for it

Plant in spring in soil that stays wet. It is a short-lived perennial. Watch for slugs and snails; it may also get powdery mildew.

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.