When used in an extraction or an infusion, the flowering parts of the tansy plant make it an excellent insect repellent. It is a perennial, and as such, forms vigorous new shoots each year. These can measure up to 1.5m, with multiple stems, abundant flowers, and a strong scent that is hated by many insects but not by all, such as the aphid-devouring ladybird. We grow it on our grassland where it tends to be invasive.