Heartleaf oxeye

Heartleaf oxeye: how do you recognise it?

Habit

Large clump 1.2–1.8 m tall and about 1 m wide, with sturdy, branching stems.

Foliage

Large, heart-shaped basal leaves up to about 30 cm long with a toothed edge; smaller, stem-clasping leaves higher up.

Flower

Yellow daisies 6–8 cm across with narrow ray florets and an orange-yellow centre, in July and August.

Roots

Thick rootstock that slowly widens the clump; easy to divide.

Flowering: July–August · Plants: March–May and September–October · Pruning: March and August

Why grow it?

• Imposing leaves and flowers in a spot where many other perennials fall short: damp partial shade.
• Flowers in July and August with yellow daisies against a backdrop of big leaves.
• Very robust: once established it needs little maintenance.
• Bees and butterflies visit the flowers.
• Gives height and structure at the back of a border or at the edge of a pond.

Heartleaf oxeye: where does it grow best?

• Partial shade is ideal; sun is fine as long as the soil stays moist.
• Rich, humus-rich soil: loam, clay or peat, acid to chalky.
• Moist to wet; in dry summers its leaves soon flag.
• Allow about 1 m per plant.
• Sheltered from strong wind, because the tall stems can bend.

Light

Sun and partial shade

Soil type

Loam, clay or peat

Acidity

Not fussy

Moisture

Normal or wet

Size

1.6 m tall, 1 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Rodgersia: Large, hand-shaped leaves in the same damp partial shade.
• Meadowsweet: Frothy plumes in summer, for damp soil.
• Plantain lily: A leafy edge in front of the tall stems.
• Daylily: Flowers at the same time and likes the same moist soil.

Heartleaf oxeye: when and how to plant it?

Plant in March–May and September–October.

1. Plant in March–May or in September–October, when the soil is not frozen.
2. Dig a hole twice as wide as the root ball and mix in plenty of compost.
3. Set the plant at the same depth as in its pot, with the top of the root ball level with the soil.
4. Leave about 1 m between plants.
5. Water thoroughly straight away and keep the soil moist in the first season.
6. Spread a thick layer of leaf mould or compost mulch around the plant.

Care

Water

Keep the soil moist at all times. In dry summers water generously at the base, otherwise the big leaves hang limp.

Feeding

A layer of compost or well-rotted manure in spring.

Mulching

A thick layer of leaf mould in spring keeps the soil cool and moist.

Support

Usually not needed, but in a windy spot plant supports or shelter help.

Spent flowers

Cut the flower heads off before they set seed, otherwise it self-seeds everywhere.

Dividing

Dividing the clump every 3–5 years, in spring or autumn, keeps it vigorous.

Tip: Cut the seedheads off in August before the seed ripens: that keeps self-seeding under control. Water generously in dry summers.

Heartleaf oxeye: when to prune it?

Pruning months: March and August.

When: In March, down to just above the ground; in August, cut off the faded flower heads.

How:

• In March, cut all the old stems and leaves back to just above the ground.
• In August, cut the faded flower heads off before the seed ripens.
• During the season, remove dead or broken stems at the base.

Caution: If you leave the seedheads on, you will have dozens of seedlings next year.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September–October: cut the clump with a spade into pieces with roots and shoots and replant at once.

Seed

Sow fresh seed outdoors in autumn, or in spring in seed trays; press the seed in without covering it, as it germinates in light. Seedlings may differ from the parent plant.

Heartleaf oxeye: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, down to about −30 °C: no protection is needed in Belgium.
• The leaves die back in autumn; cut everything back in March.
• In a pot: too big for most pots; plant it in the open ground.

Diseases and pests

• Slugs: They eat young leaves in spring. Collect them in the evening and protect the young shoots.
• Flagging leaves: A sign of drought in a spot that is too sunny. Water generously and mulch thickly.
• Powdery mildew: White powder on the leaves at the end of summer, especially in dry weather. Water at the base and cut off affected leaves.
• Self-seeding: Seedlings come up everywhere. Cut the flower heads off in time and pull the seedlings out.

Through the year

• March: Cut all the old stems and leaves back. Add compost. Plant or divide.
• April: Plant or divide. Apply a thick layer of mulch.
• May: Plant. Watch for slugs.
• June: Full growth. Water generously in dry weather.
• July: Flowering begins. Water in dry weather.
• August: Full flower. Cut off faded flower heads before the seed ripens.
• September: Plant or divide. Collect or sow seed.
• October: Plant or divide. Leave the foliage.
• November: Dormant. The leaves die back.
• December: Dormant.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The genus name Telekia refers to the Hungarian count Sámuel Teleki.
• The plant used to be called Buphthalmum speciosum; Buphthalmum means ‘ox-eye’ in Greek.
• In the wild it grows along streams and in damp mountain woods.