Asked May 28, 2015, 8:24 AM EDT

After several years of having beautiful Bearded Iris' Yhey stopped blooming for 2 years.Finally this year they all came back but they were all white and I was very disappointed because at one time I had some of the most beautiful flowers in this area and had many compliments.What happened to my colorful Iris'?

Venango County Pennsylvania

1 Response

There could be a number of reasons your iris have stopped blooming. I’ll list the following and you can determine if one or more of the conditions apply to your situation:

1) Not enough sunlight. Iris require 6+ hours of sunshine to bloom. Do you have any trees or shrubs that have encroached or shaded your iris plantings?

2) Too much mulch. Irises do not do well when buried in mulch or if buried too far below the surface. Since you iris bloomed in the past perhaps they have been mulched too heavily.

3) Feeding with a high nitrogen fertilizer will encourage leaf growth but at the expense of flowers. Have you applied a super phosphate fertilizer, bone meal, or all-purpose 6/10/10 fertilizer? All of these would encourage flower growth.

4) Irises typically do not change color. One possible explanation is that your original irises may have been bee-pollinated within the last few years. The seeds from those crosses may have ripened, dropped, and germinated among the original plants, and now you have a bunch of new seedlings blooming within your original clumps. Iris seed does not grow true to the parent plant and may well have produced some new colors in your iris bed. One way to get all of this sorted out is to place a tag around each bloom stalk to identify its color, then dig and divide all of the rhizomes 6-8 weeks after bloom, replanting each color separately about 2' apart so they won't crowd each other too soon. Remove any seed pods that may form before they have a chance to ripen to avoid a repeat of this problem in your garden.