Leucadendrons are short-day plants: A preliminary report
In order to extend the flowering season, Leucadendron cultivars 'Safari Sunset', 'Rosette', 'Chameleon', 'Laurel Yellow', 'Long Tom', 'Blush' and 'Jubilee Crown' were grown under long-day conditions from 10 February 2003 to 22 July 2003. Plants within a commercial plantation established in 2000 were used for this study while plants in the same block not affected by the artificial light source served as control plants. Incandescent lamps (100 W) were suspended 1.5 m above the plants with one lamp for every two plants. Long days were effected by artificially lighting the plants from 17:00 to 07:00, thus subjecting the plants to a 24 hour photoperiod. In all varieties treated, plants grown under natural short days of autumn and winter initiated flowers and anthesis occurred in mid-July, end-August and mid-August respectively for 'Safari Sunset', 'Rosette' and 'Chameleon'. Plants of all varieties grown under long-day conditions failed to form flowers. Flower initiation occurred after long days were discontinued on 22 July 2003, under natural short days of winter. Anthesis of these plants was delayed by ca. two months. By manipulation of day length all-year flowering of Leucadendron should be possible.