ASHS 2015 Annual Conference

Vitex negundo, cut-leaf chastetree, is a deciduous multi-stemmed shrub or small tree used in landscapes.  Plants bloom in late spring. Flowers are lavender-colored and foliage is highly dissected. Height may reach 3 to 6 m with a spread of 5 to 8 meters. This drought-tolerant plant may be grown in USDA cold hardiness zones 6A through 9B.  During cold winters in zones 6 and 7, it may die back to the ground, but will likely re-grow from the roots and produce a flowering shrub during the following summer, as flower buds are formed on new growth. Interest is strong among growers and consumers for improved vitex cultivars, including sterility, as vitex can be weedy.  Seeds from V. negundo 'Heterophylla' were irradiated with 3krad gamma radiation in 2006.  Seeds were germinated and a plant with potential ornamental qualities was selected.  This plant was propagated and planted in replicated plots in Griffin, GA (zone 8A) in 2009.  Evaluations continued for five years. This selection has been named 'Little Madame'.  'Little Madame' is smaller than 'Heterophylla' and has a denser, more compact form.  Internodes are shorter in 'Little Madame' and multiple branches occur at the nodes, while 'Heterophylla' has the typical Vitex pattern of two shoots per node. Flower color is a dark violet-blue on both cultivars. 'Little Madame' sets very few viable seeds, but is readily propagated through stem cuttings.