How to Grow Feverfew in Australia

Feverfew (Tanacetum parthenium, family Asteraceae) is a short-lived, bushy perennial grown for its sprays of small white daisies and its pungent, lobed, yellow-green leaves. The store sells plain feverfew seeds, to about 60 cm, and 'Golden Ball', a compact double yellow pompom form to about 30 cm. It grows from Hobart to Darwin, as a dry-season annual in the tropics, and self-sows freely. The step most growers get wrong is burying the seed, which needs light to germinate.

Three mistakes that matter

1. Covering the seed. The seed is dust-fine and light helps it germinate, so a layer of mix on top can leave a tray bare. Press it onto the surface instead, as Germinating the seed describes.
2. Planting it in heavy, wet soil. Feverfew will not tolerate soil that stays wet, and roots rot there through a cold, rainy winter. Grow it in free-draining soil or a raised bed, and water only when the top few centimetres dry out.
3. Letting every flower set seed. A plant left to seed sows itself across the garden and into paths and vegie beds. Shear off spent flowers promptly, and keep only the few seedlings you want to replace old plants.

When to plant

Warmth and light decide sowing, not frost. Seed germinates best with the mix between 15 and 24°C, which suits spring and early autumn in most zones. Autumn sowings, around Anzac Day in warm districts, often flower earlier and on longer stems than spring sowings. Plants are short-lived, but one sowing usually carries on through self-sown seedlings.

At the cold edge of a window, start seed indoors on a bright windowsill or a heat mat. At the hot edge, sow into shaded trays and plant out once the heat breaks.

Site, soil and setup

Feverfew grows in any light, well-drained soil in full sun, and it sulks in heavy ground that holds water.

Container growing

Both forms grow well in pots, and 'Golden Ball', at about 30 cm, suits pots, window boxes and hanging baskets. Give one plant a pot of at least 10 L and 25 cm across, filled with a premium potting mix. Plain feverfew reaches 60 cm, so it needs a larger, heavier pot in a windy spot.

• Watering: water when the top 2 to 3 cm of mix is dry. Let the pot drain freely, never standing in a saucer.
• Feeding: a fish and seaweed blend at half strength, about 12 mL per 9 L, fortnightly from spring to early autumn.
• Position: full sun, or morning sun and afternoon shade in hot districts, where pots dry out fast.
• Refresh: replace the plant with a young seedling every few years, since it is short-lived.

Germinating the seed

Feverfew seed has no dormancy to break. It needs only moisture, mild warmth and light, and fresh seed germinates quickly and well. In seed bank tests at the Royal Botanic Gardens, Kew, untreated seed gave 95 to 100 per cent at 15 to 21°C in daily light.

The seed is tiny, about a tenth of a gram per thousand, with too little food to push a shoot through much soil. The store's 'Golden Ball' listing gives emergence in 1 to 2 weeks at 21 to 24°C. No germination rate is recorded for home trays. Sow a pinch of three or four seeds for each plant you want, and thin to the strongest.

For more on handling seed this small, see how to sow tiny seeds without losing them.

When nothing comes up

• Buried too deep. Seed under a layer of mix often stays put. Sow again on the surface and press it in.
• Washed away. A watering can floods fine seed into clumps or down the sides. Water from below, or mist the surface.
• Dried out. Surface seed dries quickly in sun or wind. Cover the tray with clear plastic or glass until the first leaves show.
• Too cold or too hot. A cold sill in winter or a hot glasshouse in summer slows it; aim for 15 to 24°C.
• Old seed. Seed stored warm and damp loses vigour. Kept cool and dry, it stays good for several years: in laboratory storage, viability halves after about five.
• Given up too soon. Keep the tray moist and in the light for five weeks before sowing again.

Sowing Seeds

Start feverfew in trays or punnets for the most even stand, or sow it straight where it is to grow. Both routes begin with seed pressed onto the surface, as Germinating the seed explains.

Starting in trays

• Fill a punnet or cell tray with fresh seed raising mix, firm it lightly and water it well.
• Scatter a pinch of seed per cell, press it on with a flat board, and do not cover it.
• Stand the tray in bright light out of hot afternoon sun, and keep the surface just moist.
• Thin each cell to the strongest seedling once the first true leaves appear.
• Move seedlings into their own small pots 2 to 4 weeks after sowing.

Sowing direct

Rake the bed fine and level, water it, then scatter the seed thinly and tamp it onto the surface with the back of a rake. Mist daily until seedlings show, and thin them to 30 cm apart when they reach 8 to 12 cm.

Planting out

• Plant out 5 to 7 weeks after sowing, when seedlings stand about 8 cm tall.
• Harden off first (stand the pots outdoors a little longer each day for a week, so they adjust to sun and wind).
• Plant at the same depth as in the pot, 30 cm apart, and water in with seaweed solution at half strength.
• Shade young plants for a few days if hot, dry wind is forecast.

More on the move from pot to garden is in hardening off seedlings before planting out.

Care by growth stage

Drainage and restraint decide how well feverfew grows. Over-feeding reduces the essential oils that give feverfew its aroma, so feed lightly and at half strength at most.

If growth stalls in poor soil, a light application of all-purpose controlled release granular (NPK around 14-5-10) scratched in each spring can help.

Deadheading

Deadheading keeps feverfew tidy and stops it seeding across the garden. Wear gloves, as Safety explains.

• Shear off spent flower clusters as soon as they fade, before the centres turn brown.
• Cut the whole plant back after the main flush of flowers to encourage a fresh mound of leaves.
• Leave two or three heads to ripen if you want seed or a few replacement seedlings.
• In frosty districts, cut plants back to low leafy growth once frost blackens the tops.
• Divide an old clump in spring, or root basal cuttings, to renew it.

For renewing a tired clump, see dividing perennials.

Companion planting

Choose neighbours that like the same sun and dry, free-draining soil, and that draw the insects that eat aphids.

Grows well with

• Yarrow, which shares its liking for sun and lean soil and draws predatory insects.
• Alyssum, a low edging whose flowers attract hoverflies and other aphid predators.
• Dill, whose flat flower heads also feed aphid predators.

Keep apart

• German chamomile, a look-alike daisy; grown side by side, the two are easily picked by mistake.
• Mint, whose spreading roots and liking for moist soil do not suit feverfew's dry bed.

Harvesting Leaves and Flowers

Pick young leaves before the flower stems form, and cut flowers for the vase when each cluster is about three-quarters open. For drying, cut when the cluster is almost fully open.

• Wear gloves, and cut in the morning once dew has dried.
• Take no more than a third of a plant at one picking.
• Cut whole stems with secateurs just above a leaf joint.
• Hang small bunches upside down in a dry, airy, shaded room to dry.
• Dry until leaves crumble and stems snap cleanly.

Store dried leaves and flowers in a well-closed jar in a cool, dry, dark cupboard. Label the jar with the botanical name and the picking day. Fresh stems last well in a vase. The leaves and flowers carry sesquiterpene lactones, chiefly parthenolide, which can irritate skin and mouth, so read Safety before any other use.

Traditional use and history

Feverfew is a worn-down form of febrifuge, from the Latin febrifugia, and records its old reputation against fevers. Country names include featherfew, featherfoil, flirtwort and bachelor's buttons. In Germany it is Mutterkraut, the mother herb, a name that echoes its place in women's traditions.

The species name is less certain. Plutarch told of a workman who fell from the Parthenon while it was being built, and one reading links the plant to him. Another derives it from the Greek parthenos, a maiden.

Mrs Grieve's A Modern Herbal found it growing in every hedgerow in England. She told readers to watch it for snails, slugs and black fly.

Feverfew is native to south-eastern Europe as far east as the Caucasus. It has naturalised across Europe, the Americas and parts of Australia, including New South Wales, Queensland, Victoria, South Australia, Tasmania and Western Australia.

Safety

Happy Valley Seeds sells feverfew as seed for growing. Nothing here is advice to eat or take any part of the plant. Anyone considering using a plant should first seek advice from a qualified health practitioner.

If someone collapses, stops breathing, has a seizure or has a severe allergic reaction, call triple zero (000). For any suspected poisoning, call the Poisons Information Centre on 13 11 26 without waiting for symptoms.

Common problems

No seedlings. Usually seed buried too deep or allowed to dry out; see Germinating the seed and its list, When nothing comes up.

Tall, pale, floppy seedlings. Too little light on a windowsill stretches them. Move trays to brighter light and turn them daily. Read more

Plants that rot or die over winter. Heavy, wet soil is the usual cause; see Three mistakes that matter.

Plants that collapse in humid summer heat. Feverfew dislikes long, hot, humid spells. In the tropics and subtropics, grow it through the cooler, drier months and treat it as an annual.

Old plants that thin out and die. Feverfew is short-lived, and a plant often declines after a few years. Keep a self-sown seedling or a division coming on to replace it.

Seedlings everywhere. Plants left to seed spread freely; see Deadheading.

Pests and diseases

Feverfew has few serious pests, and most trouble comes from sap-suckers in dry heat or from wet soil.

Aphids (family Aphididae). Small, soft green or yellow insects cluster on soft shoot tips and leave sticky honeydew and sooty mould. Squash small colonies, hose them off with a strong jet, or spray insecticidal soap under the leaves as the label directs. Read more

Two-spotted mite (Tetranychus urticae). Leaves turn yellow-mottled and stippled, mostly on the undersides, and numbers build fast in hot, dry weather. Mist the undersides, keep plants watered, and avoid broad sprays that kill the predators which control mites. Pale winding trails, not stippling, are the work of a tiny insect feeding inside the leaf; trimming off the worst leaves is usually enough. Read more

Common garden snail (Cornu aspersum) and grey field slug (Deroceras reticulatum). Both graze seedlings at night in damp weather. Hand-pick them after dark, or scatter an iron-based snail bait thinly as the label directs. Read more

Damping off (Pythium species and Rhizoctonia solani). Seedlings rot at soil level and collapse, most often in wet mix. Use fresh seed raising mix and clean trays. Read more

Prevention first

• Keep seed trays clear of rain and hose splash, which spread damping off.
• Water the soil, not the leaves, and avoid overwatering in cool, wet weather.
• Check shoot tips and leaf undersides weekly through spring and summer.
• Clear leaf litter, boards and loose pots from around seedlings, where snails shelter.

Tips

1. Save seed from one or two ripe heads, when the centres have turned to dry brown seed. Store it in a paper envelope in a cool, dry place.
2. Grow feverfew where bees can reach it: bees and butterflies visit the flowers through summer and autumn.
3. Lift unwanted self-sown seedlings while they are small, and pot a few on to give away or to fill gaps.