Lesser spearwort

Lesser spearwort: how do you recognise it?

Habit

Loose clump 20–40 cm tall and about 30 cm wide, with trailing to ascending stems.

Leaves

Narrowly lance-shaped to oval, with a smooth or slightly toothed edge; the lower leaves have a stalk.

Flowers

Glossy yellow, 1–2 cm across, with five petals, single or in small groups, from June to September.

Fruit

A small round head of dry seeds, as in other buttercups.

Roots

Fibrous roots; the stems root at the nodes where they touch wet soil.

Pond zone

Marsh zone: from wet bank soil to 10 cm below the water surface.

Flowering: June–September · Plants: April–June · Pruning: August and October

Why grow it?

• Flowers all summer, from June to September, with cheerful yellow flowers.
• Small and modest: ideal for the wet edge of a small pond or pool.
• A native plant that feeds bees, hoverflies and other small insects.
• Softens the pond edge and gives frogs and newts cover at the water’s edge.
• Also grows in acid, poor soil, where many other marginal plants struggle.

Lesser spearwort: where does it grow best?

• Sun to partial shade; it flowers best in full sun.
• Wet sandy, loamy or peaty soil, acid to neutral and preferably not too rich.
• Always wet: in the marsh zone or in shallow water up to 10 cm deep.
• Plant about 30 cm apart, ideally in groups of three to five for a good effect.

Light

Sun and partial shade

Soil type

Sand, loam or peat

Acidity

Acid or neutral

Moisture

Wet

Size

0.4 m tall, 0.3 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Marsh marigold: Flowers as early as March–May, so the pond edge stays yellow from spring to autumn.
• Water forget-me-not: Sky-blue flowers in the same wet zone, lovely next to the yellow.
• Marsh cinquefoil: A native plant for acid, wet soil, with dark purple flowers.
• Water plantain: Broad leaves and airy sprays of white flowers in shallow water.

Lesser spearwort: when and how to plant it?

Plant in April–June.

1. Plant from April to June, when it is in growth.
2. Plant straight into the wet bank soil or into a small aquatic basket with poor, sandy garden soil or clay, without potting compost or fertiliser.
3. Set the plant so that its base sits 0–10 cm below the water surface.
4. Leave about 30 cm between plants.
5. Top a basket with 2–3 cm of gravel so the soil does not wash out.
6. On the bank: water in and keep the soil wet until it has established.

Care

Water

The marsh zone must never dry out. In dry summers top up the pond with rainwater, which is soft and suits this plant.

Feeding

Not needed: it likes poor soil, and fertiliser encourages algae.

Self-seeding

It seeds itself a little in wet mud. Leave the seedlings or remove them where they do not fit.

Tidying

In October cut off dead stems so they do not rot in the water.

Dividing

Every 3 years, or when the clump gets too big, divide it in spring.

Tip: Plant it in the shallow margin, up to 10 cm under water, and not among vigorous growers: then this little buttercup will flower all summer.

Lesser spearwort: when to prune it?

Pruning months: August and October.

When: It hardly needs pruning. In August you can cut off spent flower stems, and in October cut away the dead foliage.

How:

• Cut off spent flower stems if you want to limit self-seeding; otherwise leave them.
• In October cut yellowed stems back to just above the soil or the water surface.
• Wear gloves: the sap can irritate the skin.
• Put the clippings on the compost heap, never in a field with grazing animals.

Caution: The fresh sap is poisonous and irritating: work with gloves and wash your hands afterwards.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In April–May lift the clump or take it out of the basket and pull or cut it into pieces with roots. Replant straight away in wet soil.

Rooted stems

In summer cut off a stem that has already rooted at the nodes and plant it in a pot of wet soil or in the marsh zone.

Lesser spearwort: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, to about −30 °C: no protection is needed in Belgium.
• In autumn most of the foliage dies back; the plant overwinters in the wet soil and grows again in spring.
• In a tub or mini pond: put it in a sheltered spot so the water does not freeze to the bottom.

Diseases and pests

• Drying out: Limp or brown leaves in a dry summer, when the water level drops. Top up the pond with rainwater in good time.
• Crowded out: Vigorous neighbours such as bulrush or reed take its place. Give it a spot of its own and keep strong growers in baskets.
• Too many seedlings: Young plants in every wet corner. Cut spent stems in time and pull out the seedlings.
• Aphids: Aphids on stems and flower buds in summer. Hose them off; fish, pond creatures and ladybirds clear them up.

Through the year

• April: Plant or divide. New leaves appear.
• May: Plant. Rooted stems can already be taken.
• June: First flowers. Planting is still possible.
• July: In flower. Keep the marsh zone wet in dry spells.
• August: In flower. Cut spent stems if you want to limit self-seeding.
• September: Last flowers.
• October: Cut back dead stems, wearing gloves.
• November: Dormant. The plant overwinters in the wet soil.

Edible and useful

Not edible. All parts of these buttercups are poisonous, especially when fresh: when the plant is damaged it releases protoanemonin, an acrid compound that causes a burning feeling in the mouth, drooling, vomiting and stomach ache, and redness and small blisters on the skin. The acrid taste puts most animals off: cows and horses leave fresh buttercups standing in the field, but in hay they are harmless, because the compound breaks down as it dries. So never throw fresh mowings or trimmings into a field, run or pen, and do not give them to rabbits or guinea pigs. Do not let children chew the stems or flowers, and wear gloves when dividing and trimming. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Ranunculus means ‘little frog’, from the Latin rana: many buttercups grow in wet places where frogs live.
• The poisonous substance in the sap breaks down when the plant dries: in hay, buttercups are far less harmful than fresh in the field.
• The species name flammula means ‘little flame’, probably after the narrow, flame-shaped leaves.