The double flowering form can be propagated vegetatively, but at a premium price. Potted up during the summer previous to spring sales and stored overwinter, this plant sells itself when in bloom at a garden center outlet. The double flowers have a good 2 to 3 weeks duration time which adds to their value for spring sales. The plants can be enjoyed best, however, if planted as soon as possible into the landscape. In the spring, the plants are covered with blue flowers that are held above the foliage forming a beautiful blue carpet.
Propagation is by seed or division.
It should be possible to keep the plants flowering year-round by manipulating photoperiod and temperature. This should allow sales of flowering plants for landscape use from spring through most of the summer. Zinnia angustifolia HBK, however, is virtually disease free. Until now only the orange flowered cultivar 'Classic' was available. The single, daisy-like flowers measure about 2.5 cm and appear in mass on plants reaching 35 cm.