HISTORY OF THE DAHLIA.

New Zealand Herald, Volume LXVI, Issue 20152, 12 January 1929, Page 5 (Supplement)

HISTORY OF THE DAHLIA.

MODERN IMPROVEMENTS. Tlio introduction of 1 lie dahlia into Europe, resulting as it did in the many types and forms, with their numerous varieties, now in cultivation, has placed the gems in the forefront of modern garden flowers. In its original form it was indigent to tho sandy meadows of Mexico, and comprised only i few species. ]l was introduced to Spain in 1789 and from there it was taken to England, hut this importation, and another in ' 1804 are now lost to cultivation, A third importation. however, was brought from France in 1815, and from this tho numerous present forms have been derived. The common dahlias now in cultivation probably all originated from the cpecies coccinea mercki and variabilis. The cactus dahlia, until recently the most popular, originated under cultivation in Mexico from a variety named Juarezii (Juarez's) a distinct form with overlapping scarlet petals, this remarkable variety being the parents of the wellknown cactus and semi-cactus varieties. THE EARLY TYPES. In their earliest stages of cultivation hur important classes, known as show fancy, bouquet or pempone anc i singleflowered predominated, but these were followed by the advent of the cactus section, which revolutionised dahlia growing by its irregular form and pleasing diversity in colours. Collarette dahlias, an attractive type of single riower with a collar or circle of small secondary flowers around the centre made a distinct break which was closely followed by the introduction of the paeony-flowered section, remarkable for its freedom of flowering, the immense size of the blooms and the length' of flower stems. This section is appreciated for garden decoration and cutting.

The modern type of dahlia has become one of the most popular flowers all over the civilised world, and has taken a foremost place as the reigning beauty among autumn flowers. Specialists in England, Europe and America have devoted their energies to bringing the garden decorative types up to the highest perfection, and have attained results that have revolutionised dahlia culture. The flowers stand erect on exceptionally long wire-like stems, every bloom showing to advantage both on the plants and when cut. They vary in size from small to medium and attain an enormous size, as far as the giant decoratives are concerned. The hybrid cacti dahlias are cross between the cactus and decorative types, showing the elegant flower of the cactus upon the long, stiff stem of the decorative.

Each year produces a batch of novelties superior in some form or other to existing varieties and necessitating an annual revision of the lists. The range of colours is wide and the diversity great. In the variety " Xagels Idfal," a Belgium production, the nearest approach to the •" Blue Dahlia," has been attained. American varieties now occupy a prominent position among decorative dahlias, the most recent novelties being listed at very high prices.

GENERAL CULTURAL DIRECTIONS.

Dahlias are propagated from seeds and cuttings and by division of the roots. They will thrive in almost any garden soil, but an open, sheltered situation should be chosen. Farmyard manure well mixed with soil in each hole before planting is the best fertiliser Fowl manure sparingly used is also suitable. Of artificial manures, blood and bono and superphosphate, in equal proportions, mixed with the soil are good. When planting in rows allow 3ft. apart between each with 20in. between each plant in the rows. If not in rows allow 3ft. from plant to plant. Staking is absolutely necessary and should De done at. the time of planting to avoid injuring the roots. Dahlias are late summer and autumn-flowering plants. Consequently the middle of November is the best time to plant, though this may be prolonged to about December 20. INSECTS AND DISEASES. The dahlia, like all other flowers, has its post 3 and diseases. Iu the earlier stages of growth thrips and red spider are apt to attack it, necessitating a timely spraying with Black Leaf 40, or Gishurst's Compound. Cut worms or leather jackets sometimes affect a few of the plants by eating around the stems at the surface of the soil. To combat these hghtly stir the surface soil around the affected plants and find the grub. Later caterpillars bore into the flower-buds and and flowers. As j. remedy spray with arsenate of lead paste. TRAINING THE PLANTS. Always adopt the system of growing the plants upon one stem from the grounJ. When the stem Is about 9in high pinch the toj) out. This induces the plant to make about four main growths. These in turn produce a number ol lateral growths, some of which must be removed leaving only sufficient to produce nice shapely plants Some growers place more 'han one stake to each plant to enable them to tie out the branches more systematically. This system, however, can only be adopted where a few plants

flre grown. The dahlia protlucos a multitude of flower buds, consequently disbudding is necessary to produce good blooms and maintain vigour in the plants. During the flowering period the dahlia requires to bo liberally watered, and being a gross-feeder liquid manures should bo occasionally given.