Fireflies, or whatever you call the insects that light up the night-when you see them, they're a sure sign of warm summer weather. Similarly, this new Yarrow collection will light up your summer garden. These plants differ from other Yarrow due to their taller nature without compromising beautiful habits and sturdiness.One of the very best Yarrows for lasting color throughout the summer. Bright yellow flowers contrast with dark gray green foliage. Upright habit.