Bogbean

Bogbean: how do you recognise it?

Habit

A low plant 20–30 cm tall, with thick, creeping stems that run over soil and water and spread to 60 cm or more.

Leaves

Trifoliate: three smooth, oval, slightly thick leaflets on a long stalk, like those of a broad bean.

Flowers

An upright cluster above the leaves, with pink buds and white, star-shaped flowers with five lobes covered in fringed white hairs; the outside is often tinged pink.

Fruit

A round capsule holding seeds that can float.

Roots

The thick, spongy stem roots into the mud at the nodes.

Flowering: April–June · Plants: April–June · Pruning: July and September

Why grow it?

• One of the loveliest native pond plants: fringed white flowers of surprising delicacy.
• Flowers in spring, when most other pond plants have yet to start.
• Bees and bumblebees visit the flowers.
• The creeping stems grow over the edge and hide the pond liner or the rim of the basket.
• Native: an asset to a wildlife pond or bog garden.
• Also grows in partial shade and stays low, so it suits smaller ponds.

Bogbean: where does it grow best?

• Sun to partial shade; it flowers most freely in sun.
• Wet, humus-rich soil: peat or loam, acid to neutral and preferably not too rich.
• At the pond edge, in boggy ground or in shallow water with 0–15 cm of water above the soil.
• Allow 40–60 cm per plant; the stems creep further if you let them.
• Clean, soft water is ideal; top up with rainwater.

Light

Sun and partial shade

Soil type

Loam or peat

Acidity

Acid or neutral

Moisture

Wet

Size

0.3 m tall, 0.6 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Marsh marigold: Golden yellow flowers in April, alongside the first white clusters.
• Marsh cinquefoil: A native marsh plant with deep red flowers in early summer, for the same wet, acid soil.
• Water forget-me-not: Sky-blue flowers among the trifoliate leaves.
• Cotton grass: White tufts in late spring, for a wet, acid bog bed.
• Dwarf bulrush: Slender stems with brown heads behind the low foliage.

Bogbean: when and how to plant it?

Plant in April–June.

1. Plant from April to June, as the water warms up.
2. Use a pond basket or planting bag filled with low-nutrient aquatic compost or garden soil without fertiliser.
3. Lay the creeping stem horizontally just below the surface, with the leaves above it, and firm in.
4. Cover the soil with a layer of gravel and place the basket at a depth of 0–15 cm.
5. On the bank, plant straight into wet soil, 40–60 cm apart; the soil must always stay wet.

Care

Watering

It must always stand in water or wet soil. In dry summers top up the pond with rainwater; it is less fond of hard tap water.

Feeding

Not needed, and even unwelcome: in nutrient-rich water it grows less well and algae increase.

Deadheading

In July, cut off the faded flower stems, unless you want to collect seed.

Trimming

In September, shorten stems that creep too far over the water.

Old leaves

In autumn, remove yellow and dead leaves from the water.

Tip: Let the creeping stems grow over the edge of the pond: the rim of the liner or basket disappears from view and you get a natural transition to the bank.

Bogbean: when to prune it?

Pruning months: July and September.

When: It needs hardly any pruning. In July cut off the faded flower stems, and in September shorten stems that have grown too long.

How:

• Cut faded clusters off just above the leaves.
• Cut back creeping stems that grow too far over the water or bank to the length you want; cut pieces with roots can be replanted.
• Remove yellow leaves and dead stems from the water so they do not rot.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Stem cuttings

From May to August, cut 10–15 cm pieces of creeping stem with a few leaves and lay them on wet soil or in shallow water. They root quickly at the nodes.

Division

In April–May, detach a piece of the plant with roots and replant it elsewhere.

Seed

In autumn, sow fresh seed in a pot of wet compost and leave it outside: winter cold helps germination.

Bogbean: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy to about −30 °C: no protection needed.
• The leaves die back in autumn; the thick stems overwinter in the wet soil or under water.
• Plants in baskets can stay in the pond, even if it freezes over.

Diseases and pests

• Aphids: On young leaves and flower stems in spring or summer. Hose them into the water, where fish eat them.
• Snail and slug damage: Pond snails and, on the bank, slugs eat holes in the leaves. The damage is usually limited; pick off slugs in the evening.
• Yellow leaves and slow growth: Often caused by hard or nutrient-rich water. Top up with rainwater and do not feed.
• Few flowers: Too much shade or too deep a spot. Move the basket to a sunnier, shallower place.

Through the year

• March: Remove old leaves and dead stems from the water.
• April: The first flowers appear. Plant.
• May: Full flowering: bees and bumblebees visit the flowers. Plant or divide.
• June: Last flowers. Plant. Take stem cuttings.
• July: Cut off faded flower stems. Top up the pond in dry spells, preferably with rainwater.
• August: Take stem cuttings.
• September: Shorten stems that are too long.
• October: Sow fresh seed and stand the pot outside.
• November: Remove yellow and dead leaves from the water.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The flowers come in two forms: on some plants the style sticks out beyond the stamens, on others it sits lower down. This helps insects cross-pollinate the flowers.
• The leaves taste very bitter. In Scandinavia they were sometimes used in the past to make beer bitter, instead of hops.
• In the wild its stems creep from the bank out over the water, slowly helping open water fill in and turn into marsh.