Fernleaf yarrow

Fernleaf yarrow: how do you recognise it?

Habit

An upright clump with stiff stems up to 1.2 m, about 60 cm wide.

Leaves

Finely divided, grey-green and slightly hairy, with a herby smell when crushed.

Flower

Flat heads 10–15 cm across, made up of hundreds of tiny golden-yellow flower heads, from June to September.

Scent

Leaves and flowers smell herby and slightly pungent.

Roots

A fibrous rootstock that spreads slowly, without becoming invasive.

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

Why grow it?

• A long flowering season from June to September, with sturdy, flat heads that bring horizontal lines to the border.
• Bees, hoverflies and butterflies find nectar and pollen in it.
• Very drought-tolerant: after the first year it rarely needs extra water.
• An excellent cut flower and one of the best for drying: the yellow keeps well.
• Attractive in winter too: the dry heads stay upright.

Fernleaf yarrow: where does it grow best?

• Full sun: in shade the stems become long and floppy.
• Poor, well-drained sandy, loamy or clay soil; acid, neutral or chalky. Soil that is too rich gives floppy stems.
• Dry to normally moist; on heavy clay only if water drains away well in winter.
• Lovely in the middle or back of a sunny border, in a gravel garden or in a prairie-style planting.
• Allow 45–60 cm between plants.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

1.2 m tall, 0.6 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Sage: Violet-blue spikes beside the flat yellow heads: a classic contrast.
• Catmint: A soft blue cloud for the same dry, sunny spot.
• Ornamental grasses: Airy stems next to the solid heads, in winter too.
• Sea holly: Steel-blue globes that also tolerate drought and dry well.
• Coneflower: Pink discs beside the yellow heads, for bees and butterflies.

Fernleaf yarrow: 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 wet.
2. Dig a hole slightly larger than the pot; on heavy soil, mix in some coarse sand or gravel.
3. Set the plant at the same depth as in the pot and firm the soil well.
4. Space plants 45–60 cm apart; it looks best in a group of three.
5. Water when planting and in dry spells for the first weeks, then only rarely.
6. Do not put fertiliser or compost in the hole; a gravel mulch keeps the base dry.

Care

Watering

In dry spells during the first year. After that only in long, hot droughts.

Feeding

Not needed: fertiliser makes the stems floppy.

Deadheading

Cut faded heads back to a leaf or side bud for a second flush, or leave the last ones standing for winter.

Support

In a windy spot or on richer soil a low support ring may be needed.

Dividing

Every three to four years in spring, to keep the clump young and free-flowering.

Tip: Plant it in full sun on poor, well-drained soil and do not feed it: that keeps the stems sturdy. For drying, cut the heads when fully open and hang them upside down in a dry, dark place.

Fernleaf yarrow: when to prune it?

Pruning months: March and July–August.

When: Cut off faded flower heads in July–August, and last year’s old stems in March.

How:

• In summer, cut faded heads back to just above a leaf or side bud: new flowers often follow.
• Leave the last heads standing in autumn: they look good in winter.
• In March, cut all old stems down to just above the new leaves at the base.
• For the vase or for drying, cut when the heads are fully open and firm.

Caution: Wear gloves if you have sensitive skin: the sap can irritate.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

Every three to four years in March–April. Cut the clump into pieces with a few shoots and roots each and replant straight away.

Seed

Sow indoors in March–April in a warm room. Do not cover the fine seed, as it needs light to germinate. Plants usually only flower well from the second year.

Cuttings

In spring, take cuttings from young shoots at the base and root them in sandy compost.

Fernleaf yarrow: how does it get through the winter?

Hardy to −30 °C.

• Hardy to about −30 °C: no protection is needed in Belgium.
• It dislikes heavy, wet soil in winter; make sure drainage is good.
• Leave the dry heads until March: they look lovely covered in frost.

Diseases and pests

• Falling stems: Soil too rich, too much water or too little sun. Do not feed, move it to a sunnier spot or use a support ring.
• Powdery mildew: White powder on the leaves, especially in dry weather in late summer. Leave space around the plant and cut off affected leaves.
• Aphids: On young stems and buds. Wash them off with water; ladybirds and hoverflies help too.
• Rot: In wet winters the clump can rot. Plant it higher, in better-drained soil.

Through the year

• March: Cut old stems down to just above the new leaves. Divide. Sow indoors.
• April: Plant. Sow indoors.
• May: Plant. Put in a support ring if needed.
• June: Flowering begins. Cut heads for the vase.
• July: Flowering. Cut off faded heads for a second flush.
• August: Flowering. Pick heads for drying. Cut off faded heads.
• September: Last flowers. Plant.
• October: Plant. Leave the last heads standing.
• December: Rest. The dry heads decorate the garden.

Edible and useful

Not edible. Fern-leaf yarrow and sneezewort are mildly poisonous: eating them causes vomiting and diarrhoea, in children as well as in dogs, cats and horses. Sneezewort is so called because it was once used as snuff: do not sniff or eat any of it. The leaves and sap can cause a rash in sensitive people, sometimes worse in sunlight: wear gloves if you prune or divide a lot. They are not kitchen herbs: do not use them in tea or salad. Do not plant them in or beside a field, and do not throw trimmings near the feed. 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.

Butterflies

Nectar for butterflies.

Did you know?

• The genus is named after the Greek hero Achilles.
• What looks like one large flower is actually hundreds of tiny flower heads packed together.
• The species name filipendulina refers to the divided leaves, which resemble those of Filipendula, such as meadowsweet.