Abstract Mordants are materials used to fix long periods of colour on selected fabrics or fibres. The current research aimed to dye natural fibres like palm leaf (Borassus flabellifer L.), korai grass (Cyperus pangorei L.), banana fibre (Musa accuminata L.), screw fine fibre (Pandanus), sisal fibre (Agave sisalana Perrine), and pineapple fibres (Ananas comosus L.) with Calendula officinalis plant flower dye. The dye was fixed to the selected fibre material with the help of different mordants. The Calendula officinalis flower dye produced different colours, like black, brown, orange, sandal, yellow, etc., on the dyed materials. The different colour formations on the dyed materials are based on the mordents used to fix the dye. The mordants tonify the different colours in the same dyestuff of Calendula officinalis flower dye. Mordant-based dyed natural fibres have good fastness properties against light and water. Calendula officinalis dyes have potential activity against the skin infection-causing organism Pseudomonas aeruginosa.