Effect of genotype and harvest season on quality characteristics of Cyclopia subternata: Phenolic content and sensory profile

•Genotype and harvest season affected phenolic content of C. subternata leaves.•Genotype and harvest season affected sensory profile of herbal tea.•Genotype SGD3 had the highest leaf phenolic content.•Positive aroma attributes of herbal tea were less intense for autumn harvest.•Summer harvesting delivered the better quality product.