Pyrethrum daisy is a popular attractive plant in the home garden. Best known for its natural insecticidal properties, it and is often grown as a companion plant to protect the home vegetable patch.
What you need to know about pyrethrum daisies
Name: pyrethrum daisy (Tanacetum cinerariifolium or Chrysanthemum cinerariifolium).
Height: up to 1.5m with a spread of about 1.5m; responds well to pruning.
Foliage: blue-green, typical fern-like daisy leaves.
Climate: cool temperate to temperate; withstands heat but prefers cooler conditions
Soil: well-drained, fertile loam with added organic matter; pH from slightly acidic to slightly alkaline.
Position: full sun.
Flowering: single white daisy flower with yellow centre.
Feeding: use a long-term controlled-release fertiliser regularly.
Watering: keep moist but not wet; can withstand dry soil during cooler weather.
Appearance and characteristics of pyrethrum daisy
Pyrethrum daisy is best known for its natural insecticidal properties. Pyrethrins extracted from its dried flowers and seeds are effective in deterring and controlling sap-sucking insects like aphids, thrips, leafhoppers, harlequin bugs, white fly and caterpillars. Pyrethrum sprays can be safely used on edible plants. including vegetables and herbs.
Tasmania is the world's leading supplier of commercial pyrethrum. In spring and early summer broad acres of the countryside turn white when the plants are in bloom.
The pyrethrum daisy has blue-green typical daisy (fern-like) leaves, and masses of white daisy flowers with bright yellow centres, each carried on a slender upright stem. The plants are quite shrubby and will grow up to 1.5m tall with a similar spread in perfect conditions.
How to plant and grow pyrethrum daisy
Growing from seeds
This daisy may be grown from seed, which is available from specialist seed businesses—check online for suppliers near you. However, it is most often grown from commercially raised seedlings, which should be planted out in spring. Space plants about 45cm apart in an open, sunny location; like most daisies, they will not grow or flower well in the shade.
Climate
Pyrethrum daisy will grow well in most climates, apart from the tropics.
Soil
Pyrethrum daisy will grow in soils that range from acidic (pH 5.4) to mildly alkaline (pH 7.2). They prefer a well-drained soil enriched with plenty of compost and weathered animal manure. To get the best out of plants, add a handful of superphosphate* per square metre to the soil at planting time, and then again every spring after that.
*Most garden fertilisers now available in Australia have 0% to less than 2% phosphorus, which is not considered enough for pyrethrum daisies to thrive.
Flowering
Plants will flower from late spring right through to autumn. Flowering may not be prolific in the first year after planting, but it will increase the following year. Pyrethrum daisy is not long-lived, however—flowering will decline after 5 or 6 years. Replace plants when this occurs.
Caring for pyrethrum daisy
Like most daisies, pyrethrum daisy is quite hardy and doesn't require a great deal of attention once established.
Watering
Over summer, give your plant a deep watering once a week, or more often if the weather is particularly hot and dry. Excess moisture can cause root rot to develop, so ensure drainage is good. If plants are growing around the vegie patch or inter-planted among your crops, be careful not to over-water the daisies.
Feeding
Applications of a 6-month controlled-release fertiliser in late winter and again in early autumn will keep plants healthy and promote flowering.
Pruning pyrethrum daisy
Your plant can be lightly trimmed to maintain a neat shape, but heavy pruning is not usually needed.
Diseases and pests
Because of its natural insecticidal properties, pyrethrum daisy is not usually bothered by insect pests!
The plant may develop root rot if the soil remains too moist for extended periods after watering or rainfall. If your soil is a heavy loam or clay, add organic matter and coarse sand to it to open it up, or consider planting this daisy into raised beds or mounds to facilitate drainage.
If you like this then try
Lavender: the backbone of the cottage garden along with daisies, featuring grey-green leaves and pink to mauve flowers.
Roses: the “queen” of flowers; plants from groundcovers to rampant climbers, with flowers in all colours.
Hydrangeas: white, pink or blue dense heads of flowers on small to medium shrubs with bright green leaves
Start growing today
Check out our huge range of plants now and get your garden growing!