Dahlia imperialis

Description

Dahlia imperialis has long been a favourite amongst lovers of fast growing large leafed jungly plants, with enormous leaves and thick sturdy trunks this dahlia is an impressive addition to the garden. Originally from Mexico where it can reach heights of 8 metres tall the very tops of each stem supporting dainty pinkish white to white simple flowers which attractively hang in clusters. The main stems are so thick and being typical of all dahlias are hollow making great natural containers which local people in the past often used to store and carry water amongst other things.

For us here in the U.K our summers aren’t generally long or hot enough to produce the type of growth mentioned above, but all is not lost. I’ve been growing Dahlia imperialis for over 20 years enjoying it for its speedy growth, huge leaves a metre or more long and outrageous tropical appearance competing nicely with the Japanese banana, Musa basjoo. Plants here in West Sussex regularly reach 4 or more metres high each year, growing strongly right up to the first frosts of autumn. If you are really lucky flowers might even appear though usually, they are cut down by frost as they are produced so late in the season.

As for hardiness I’d say they are hardier than most dahlias which are generally lifted each autumn, the tubers kept frost free during the winter. However, Dahlia imperialis produces huge tubers and is a real effort to lift so here we leave in the ground and protect the plants with a heavy mulch. The choice is yours depending on how much space have and how strong you are.

As with all fast growing or large leafed jungly plants Dahlia imperialis will respond and grow faster, bigger if kept well fed and watered during the growing period. We keep our growing beds heavily mulched with composted farmyard manure and our container plants regularly watered with seaweed extract fertiliser.