Calendula Powerdaisy Plug Plants A true breeding breakthrough! These Calendula Powerdaisy Plug Plants are the first tough, disease-resistant, cascading calendulas, producing vibrantly coloured, daisy-like flowers from March until November! The half-hardy perennial plants are easy to maintain and tolerant of frost to least -5°C. With bright, bold flowers that will turn heads in your garden this year, these calendulas are a garden must-have to suit every taste. Tango - Vivid orange. Height 30-40cm (12-16"). Sunny - Bright yellow. Placed 3rd in RHS Chelsea Flower Show Plant of the Year. Height 20-30cm (8-12").