bearded Iris blooming poorly

Question

I divided them several years ago and they do not appear to be overcrowded. I planted them shallow so the tubers are showing to prevent rot. I have used a modest quantity of lime in the soil. They seem to have excellent leaf growth and size. They are mature. Any ideas on why they are relatively unproductive bloomers?

Answer 1

Use a fertilizer higher in phosphorus or even a phosphorus only amendment, like bone meal, to get them to bloom. This article will help you: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm

In addition, it can be attributed to poor pollination. Try to entice pollinators (bees, butterflies, etc.) to the area with brightly colored flowers.