Gardening Lore
Gardening probably has more “wives tales” or “lore” than most hobbies. Lore can be gathered from the numerous resources, the standby Farmers Almanac, the local Extension service, or your favorite nursery. Some of the most valuable information is generated locally and passed down through the generations. Most is sound and usually has some scientific basis. Here at Garden4Us we will try to “Explore the Lore”. This month’s article is on Pryethrums and Wormwood.
Pyrethrums deter insects in general
Pyrethrum refers to several Old World plants of the genus Chrysanthemum (e.g., C. coccineum) which are cultivated as ornamentals for their showy flower heads. It is also the name of a natural insecticide made from the dried flower heads of C. cinerariifolium and C. coccineum. Pyrethrum was used for centuries as an insecticide and as a lice remedy (“Persian Insect Powder,” “Persian Pellitory”) in the Middle East. It was sold worldwide under the brand Zacherlin by Austrian industrialist J. Zacherl.
Some members of Chrysanthemum, including these two, are placed in another genus, Tanacetum, by some authorities. Both genera are members of the daisy (or aster) family, Asteraceae. They are perennial plants with a daisy-like appearance and white petals.
C. cinerariifolium is called the Dalmatian chrysanthemum, denoting its origin in that region of the Balkans (Dalmatia). It looks more like the common daisy than other pyrethrums. Its flowers, typically white with a yellow center, grow from numerous fairly rigid stems. Plants have blue-green leaves and grow to between 45 to 60 cm in height. The plant is economically important as a natural source of insecticide. The flowers are pulverized and the active components called pyrethrins, contained in the seed cases, are extracted and sold in the form of an oleoresin. This is applied as a suspension in water or oil, or as a powder. Pyrethrins attack the nervous systems of all insects, and inhibit female mosquitoes from biting. When not present in amounts fatal to insects, they still appear to have an insect repellent effect.
Wormwood deters animals in general
The plant can easily be cultivated in dry soil. They should be planted under bright exposure in fertile, mid-weight soil. It prefers soil rich in nitrogen. It can be propagated by growth (ripened cuttings taken in March or October in temperate climates) or by seeds in nursery beds. It is naturalised in some areas away from its native range, including much of North America.
The plant’s characteristic odor can make it useful for making a plant spray against pests. In the practice of companion planting, because of the secretions of its roots, it exerts an inhibiting effect on the growth of surrounding plants, thus weeds. It can be useful to repel insect larvae but it need only be planted on the edge of the area of cultivation. It has also been used to repel fleas and moths indoors.
It is an ingredient in the liquor absinthe, and also used for flavouring in some other spirits and wines, including bitters, vermouth and pelinkovac. It is also used medically as a tonic, stomachic, antiseptic, antispasmodic, carminative, cholagogue, febrifuge and anthelmintic. In the Middle Ages it was used to spice mead.
It is a herbaceous perennial plant, with a hard, woody rhizome. The stems are straight, growing to 0.8-1.2 m (rarely 1.5 m) tall, grooved, branched, and silvery-green. The leaves are spirally arranged, greenish-grey above and white below, covered with silky silvery-white trichomes, and bearing minute oil-producing glands; the basal leaves are up to 25 cm long, bipinnate to tripinnate with long petioles, with the cauline leaves (those on the stem) smaller, 5-10 cm long, less divided, and with short petioles; the uppermost leaves can be both simple and sessile (without a petiole). Its flowers are pale yellow, tubular, and clustered in spherical bent-down heads (capitula), which are in turn clustered in leafy and branched panicles. Flowering is from early summer to early autumn; pollination is anemophilous. The fruit is a small achene; seed dispersal is by gravity.
It grows naturally on uncultivated, arid ground, on rocky slopes, and at the edge of footpaths and fields.
