'Tropicanna Black' is an erect, rhizomatous perennial with large, banana-like, dark maroon leaves and strong, erect stems bearing racemes of bright orange-red flowers from summer to early autumn.
With masses of broad fleshy leaves, cannas do best with a good supply of water, so water the plants during the summer if the rainfall is less than 1 inch per week. Water freely in a dry spell.
Cannas are not picky when it comes to fertilizer. Cannas easily bloom all summer without much effort. But for those of you who want to give your plants an extra boost, apply a 5-10-5 or 10-10-10 in the spring and, if you wish, two more times during the growing season. Fish emulsion fertilizer is a little higher in nitrogen, but is a fantastic organic alternative for feeding your cannas. Higher nitrogen fertilizers tend to increase the average height of cannas. If you have rose food or tomato food on hand, both are great options for cannas, too.
After the flower stem has been deadheaded several times and is no longer producing flowers, cut the flower stem and any attached foliage to the ground, as this can help nearby cannas get more light and flower themselves. (If you prefer, just cut the stem back to the foliage, which will last until the first frost.)
Half hardy - unheated greenhouse / mild winter - Hardy in coastal and relatively mild parts of the UK except in severe winters and a risk from sudden (early) frosts. May be hardy elsewhere with wall shelter or good micro-climate. Likely to be damaged or killed in cold winters. Plant can withstand temperatures down to -5°C (23°F)