(41-86 days. Achillea millefolium) A flowering herb / flower that typically grows as a perennial, which is defined as a plant that matures and completes its lifecycle over the course of three years or more. Common Yarrow normally grows to a forb (non-grassy) habit with a max height of 1.95 feet. This plant tends to bloom in mid summer, followed by first harvests in late summer. This plant is a great attractor for butterflies and bees, so if you are looking to attract wildlife, Common Yarrow is a great choice. Common Yarrow is a low maintenance plant and is normally very easy to grow — great for beginner gardeners!