Allamandas, the glorious golds of summer

By Dr. Bill Barrick, Executive Director

Without question, Allamandas are some of the most useful and beautiful flowering plants for our summer gardens at Bellingrath Gardens and Home. Allamandas are members of the Apocynaceae family and members of this family are noted for their milky sap. Other ornamental members of this family include many familiar plants – Mandevilla, Nerium (Oleander), Plumeria and a common annual Vinca. 

Allamandas are native to the Americas and have a fairly wide distribution from Mexico to Argentina.  In the wild, they grow along riverbanks in full sun.

For as long as I can remember, we have used Allamandas in our summer displays. We maintain stock plants of three different types of Allamandas – two dwarf shrubby forms and a vigorous vine-like form.  Although we typically plant Allamandas in late May, they don’t begin blooming profusely until late June and July when the days are longer.

Perhaps the most common Allamanda is Allamanda carthartica, which has a rambling, vine-like habit of growth. For that reason, we typically grow them in large hanging baskets which are featured on the bridge over Mirror Lake or on posts in the Great Lawn border planting. The plant features dark glossy green foliage and the brown flower buds open to glorious waxy yellow flowers. As flowers fade on the bridge, the spent flowers fall and float in the lake, giving an added bonus.

There is a dwarf form of this Allamanda named A. cathartica ‘Compacta,’ sometimes listed in the trade as ‘Dwarf Jenny.’ The dwarf form is fairly compact, reaching heights of two feet. This variety is planted in profusion along the Great Lawn.

There are a couple of other varieties worth noting – ‘Stansill’s Double’ with double flowers, ‘Hendersonii’ with considerably larger flowers and ‘Brown Bud’ with distinctly brown flower buds.

The other species called Bush Allamanda, A. schottii, has a similar growth habit and stays quite compact in the landscape. The yellow flowers are more tubular in shape but equally beautiful.

Next summer, consider using Allamandas in your garden. If you give them full sun and routine fertilization with a liquid or slow release fertilizer, you will be rewarded with flowers until fall.