Pyrethrum herb and health

This plant is native to Dalmatia but is now cultivated commercially in many parts of the world, including Japan, South Africa and parts of Central Europe. It has been grown for many years for its insecticidal properties. The derivative was originally known as Dalmatian insect powder but is now better known as Pyrethrum insecticide. I list the two species to contain this natural insecticide.

Species

(Chrysanthemum cinerariifolium)

Hardy perennial. Ht 30- 37cm (12-15in), spread 20cm (8in). Daisy-like flower, white petals with a yellow center. Leaves green/gray, finely divided, with white down on the underside.

Tanacetum coccineum (Chrysanthemum roseum)

Hardy perennial.Ht 30-60cm (12-24in) spread 30cm (12in). Large flower head which can be white or red, and sometimes tipped with yellow. Very variable under cultivation. Vivid green leaves. Native of Iran.

Cultivation

Propagation

Seeds

In spring sow into a prepared seed or plug tray and cover with Perlite. Germination is easy and lakes 14-21 days. In late spring, when the young plants are large enough and altera period of hardening oil, plant out into a prepared site in the garden 15-30cm (6-12in) apart.

Division

Established clumps can be dug up in the spring and divided.

Pests and Diseases

In the majority of cases this plant is free from pests and diseases.

Maintenance

Spring: Sow seed. Divide established plants.

Summer: Dead head (lowers to prolong season if not collecting seed.

Autumn: Divide established plants if necessary.

Winter: Fully hardy.

Garden cultivation

Pyrethrum likes a well-drained soil in a sunny spot; it is drought tolerant and fully hardy in most winters.

Harvest

The flower heads are collected just as they open and then dried gently. When they are quite dry, store away from light, the insecticide is made from the powdered dried flower.

Container growing

This herb is very well suited to be grown in containers, especially terracotta. Use the bark, peat, grit compost. Water well during the summer months, but be mean on the liquid fertilizer, otherwise the leaves will become green and it will stop flowering.

Medicinal

This herb is rarely used medicinally. Herbalists have found the roots to be a remedy for certain levers. Recent research has shown that the flower heads posses: a weak antibiotic.

Other uses

This is a useful insecticide because it is non-toxic to mammals and does not accumulate in the environment or in the bodies of animals. It acts by paralyzing the nervous system of the insects, and can kill pests living on the skin of man and animals. Sprinkle the dry powder from the (lowers to deter all common insects, pests, bed 1 bugs, cockroaches, flies, mosquitoes, aphids, spider mites and ants. To make a spray, steep 28g (1oz) of pyrethrum powder in 28ml (1fl oz) of methylated spirits and then dilute with 14 liters (3 gallons) water. The solution decomposes in bright sunlight. Therefore for maximum effect and to reduce the risk to pollinating insects and bees, spray at dusk.