Dahlia White Onesta

Dahlia ‘White Onesta’ is a white dahlia with a lemony centre which double flowers resemble water lilies. From July until the first frosts, it produces a profusion of medium-sized heads, held above bright green foliage. Of medium stature, it is an excellent dahlia for sunny borders, tall borders, white cut flower arrangements and wedding displays.

Botanically, ‘White Onesta’ belongs to the genus Dahlia and the Asteraceae family, just like the Zinnia. Native to the high plateaus of Mexico and Central America, dahlia is a tender tuberous perennial: the stems and foliage, which are deciduous, disappear after the first frosts, but the tubercle, if kept dry and frost-free, will form a new young plant the following spring. Horticulturally, this variety is classified in the group of decorative dahlias of the "waterlily" form: the flower is very double, with wide, slightly incurved ligules (or "petals"), arranged in a shallow cup.
'White Onesta’ is a Dutch introduction from Berg & Daal (Warmerdam), introduced around the year 2000; it is a mutation of the cultivar 'Onesta' which regularly features in selections of dahlias for cut flowers. The plant has a bushy, upright habit, well ramified from the base, forming a dense clump 0.90 to 1.10 m in height and 50 to 60 cm in width. The stems are sturdy, firm enough to support the flowers, except in windy sites where staking will be necessary. The foliage is medium green, formed of pinnate leaves with ovate to lanceolate lobes, 8 to 15 cm, with slightly dentate edges. The heads measure 10 to 12 cm in diameter; they are filled with wide, rounded, white external ligules, washed with cream near the centre. In the centre, ranks of shorter ligules tighten around a small greenish-yellow heart; this "lime" effect is highly sought after in contemporary displays. Flowering lasts from July to October, until the first frosts, provided you regularly remove spent flowers. In autumn, the aerial growth blackens due to the cold, while the tubercle enters dormancy.

In the garden, this white dahlia with a lemony centre integrates wonderfully into white borders or elegant cut flower arrangements. Its flower contrasts pleasantly with the plum and mauve tones of a dahlia ‘Crème de Cassis’, or with the very dark small balls of ‘Dark Spirit’. To lighten the overall effect, you can use grasses like Pennisetum orientale ‘Karley Rose’ with its smoky pink feathery spikes. In a cut flower arrangement, this dahlia pairs very well with this grass, but also with tall verbenas like Verbena officinalis 'Bampton' or slightly fuzzy foliage, for contemporary, airy and luminous displays.

Dahlias were first introduced to Europe in the 18th century not for their flowers, but as a vegetable plant: the tubercles, rich in inulin, were tested as a vegetable, their taste reminiscent of artichoke, before their incredible diversity of forms and colours established them definitively as ornamental plants.