Although ageratum is available in shades of pink and white, blue is the original and most common color. Depending on the variety, they range in size from six inches to two feet in height. They make great dried flowers, and the larger size is perfect for cut flowers. It is another ideal annual for the novice gardener, because of its ease of growth and resistance to disease. In addition, it is not as fussy about soil as other plants, and will continue to blossom throughout the summer.
Ageratum prefers sun, but will also flower in partial shade. They are easiest to grow from established plants that can be purchased at most garden centers. They are very sensitive to frost, so it is best to wait under the nights are warmer. Plant them at the same depth as the dirt enclosure in which they came. Space them about six inches apart and water well.