Soaring sales of sweet potato Beauregard have encouraged mail order kitchen garden supplier D. T. Brown to add two new varieties to its range for the 2016 season. Gardeners bought twice as many plants of the orange-fleshed, fast-maturing strain in 2015 as they did in 2014, signalling to the company the vegetable is rapidly becoming a favourite with its customers.

The new additions for 2016 are Murasaki and Bonita. Murasaki has purple skin, white flesh and a markedly nutty flavour. A little less sweet than other varieties, its high level of 'dry matter' makes it a great choice for baking, according to the company's Tim Jeffries. It matures at 90 to 110 days after planting. Bonita has both white skin and flesh, crops heavily at around 95 days and, says Tim, its tubers have a flaky texture when cooked and an excellent flavour.

Five young plants of Murasaki, Bonita or Beauregard cost £9.95, while a collection of all 15 plants costs just £19.90. Despatch to gardeners is from mid May 2016 onwards, with plants ready for potting on into 9cm pots.

Sweet potatoes can be grown successfully in large containers or in a polytunnel or greenhouse. In milder areas they will crop outdoors in a sunny position on free-draining soils. They are not related to potatoes, and their foliage does not die back in autumn.

To request a copy of the fruit and vegetables catalogue 2016, write to D. T. Brown, Western Avenue, Matrix Park, Chorley, Lancashire PR7 7NB, telephone 0845 3710532, or go online