Branched bur-reed

Branched bur-reed: how do you recognise it?

Habit

Upright clumps up to 1.2 m tall and about 60 cm wide, spreading by rhizomes.

Leaves

Long, narrow and strap-shaped, 1–2 cm wide, with a three-sided keel at the base; fresh green.

Flowers

Branched stems with small, round heads from June to August: male at the top, female below. They are wind-pollinated.

Fruit

Hard, spiky balls of 1.5–2.5 cm, green at first and later brown; they float and break up in autumn.

Roots

Creeping rhizome that spreads strongly.

Pond zone

Shallow to deeper margin: 10–40 cm below the water surface.

Flowering: June–August · Plants: April–June · Pruning: March

Why grow it?

• Unusual spiky balls from July into autumn: decorative and a good talking point.
• Fresh, grassy foliage that gives the pond edge a natural look.
• Ducks and other waterfowl eat the seeds, and birds find shelter among the dense clumps.
• Dragonflies and damselflies climb out of the water up the leaves, and tadpoles shelter around the base.
• Takes up plenty of nutrients from the water and so helps to hold back algae.
• Native and fully hardy.

Branched bur-reed: where does it grow best?

• Sun to partial shade; it forms the most seed heads in sun.
• A bottom of loam, clay or peat; acid, neutral or alkaline all suit it.
• Water depth 10–40 cm, in still or slow-moving water.
• Best in a larger pond or on a natural bank; in a smaller pond grow it in a container.
• Allow about 60 cm per plant.

Light

Sun and partial shade

Soil type

Loam, clay or peat

Acidity

Not fussy

Moisture

Wet

Size

1.2 m tall, 0.6 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Water lily: Round floating leaves and flowers in the deeper water in front.
• Flowering rush: Pink flower heads among the grassy foliage, in summer.
• Purple loosestrife: Purple spikes on the bank, excellent for bees and butterflies.
• Greater spearwort: Golden-yellow flowers in the shallow margin, in the same summer months.

Branched bur-reed: when and how to plant it?

Plant in April–June.

1. Plant from April to June, when the water warms up.
2. In a smaller pond use a sturdy container of at least 15 litres filled with heavy clay soil, without potting compost or fertiliser.
3. Lay the rhizome about 5 cm deep and top with 2–3 cm of gravel.
4. Stand the container at 10 cm depth first and lower it after a few weeks to 10–40 cm below the water surface.
5. Keep about 60 cm from other plants.

Care

Water

Not needed in the pond. In dry summers top up the pond with rainwater.

Feeding

Do not feed: fertiliser in a pond mainly feeds algae.

Keeping in check

In summer dig out rhizomes and new clumps that grow outside the container or where you want it.

Tidying

In autumn take fallen leaves out of the water.

Dividing

Every 3 years, when the container is full, divide in April–May.

Tip: Leave the spiky seed heads standing over winter: they look lovely with frost on them and ducks eat the seeds. Do cut them off if it seeds itself too freely.

Branched bur-reed: when to prune it?

Pruning months: March.

When: In March, before the new leaves appear. Leave the old leaves and the seed heads standing over winter.

How:

• Cut the old, brown leaves and flower stems off just above the water surface.
• Remove leaves that fall into the water in autumn earlier, so they do not rot on the bottom.
• Ideally leave the seed heads until winter: ducks and other birds eat the seeds.

Caution: It also self-seeds through its floating fruits. Cut off the seed heads in autumn if you do not want new plants.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In April–May take the clump out of its container and cut the rhizome with a spade or knife into pieces with a few shoots each. Replant straight away.

Seed

Collect ripe seed heads in autumn and sow the seeds in a pot of wet clay soil under a thin layer of water; leave it outside over winter. They germinate in spring.

Branched bur-reed: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, to about −30 °C: no protection is needed in Belgium.
• Leave the brown leaves and seed heads until March: insects overwinter in them and birds find shelter and seed.
• The rhizome overwinters safely in the bottom under the ice.

Diseases and pests

• Spreading too much: New clumps far outside the container or along the whole bank. Dig out rhizomes and divide the container every few years.
• Too many seedlings: Young plants in wet spots around the pond. Cut off the seed heads in autumn and pull out the seedlings.
• Fallen leaves: After storms or ice the leaves lie in the water. Remove what hangs in the water and cut back in March.
• Few seed heads: Too much shade or a young plant. A sunnier spot helps; after a year or two it flowers more freely.

Through the year

• March: Cut old leaves and stems off above the water surface.
• April: Plant or divide. The new leaves appear.
• May: Plant. Set the container at the right depth.
• June: First round flower heads.
• July: In flower. Dig out rhizomes outside the container.
• August: The spiky balls grow larger.
• September: The seed heads ripen and turn brown.
• October: Take fallen leaves out of the water. Cut off seed heads if needed.
• December: Leave leaves and seed heads for birds and insects.

Good for wildlife

Birds

Berries, seeds or insects as food, or a place to nest.

Did you know?

• Its Dutch name means ‘hedgehog head’, after the spiky fruit heads that look like a curled-up hedgehog.
• The fruits float: the plant spreads with the water, and also with ducks that eat the seeds.
• Bur-reeds used to have a family of their own, but are now placed in the bulrush family.