Daylilies and iris not blooming

Asked September 15, 2019, 7:55 PM EDT

My previously healthy west facing Daylilies are yellowing, droopy , not flowering. Some of my iris did not bloom this year either, west facing. But others closer to the sidewalk were ok.

Larimer County Colorado

1 Response

Hi ! It looks as though your irises and daylilies might need to be divided. Plants such as irises, which grow from rhizomes, and daylilies, which tend to get a "clump" of tuberous roots,require a periodic division to keep them happy and blooming well. Here is a link to a PlantTalk video on how to divide iris and daylilies: https://www.youtube.com/watch?v=VsGS5fX5I3U&index=15&list=PLF923A9DD3BD61E42
Here is a link to a Planttalk article about irises:
http://planttalk.colostate.edu/topics/annuals-perennials/1041-iris/
and iris division:
http://planttalk.colostate.edu/topics/annuals-perennials/1071-iris-division/

Bulbs need feeding twice per year, and if you are using a fertilizer that has high Nitrogen content, like perhaps a fertilizer that is labelled all-purpose, it might be causing more leaf growth, to the sacrifice of blossoms. Use a plant food that is labelled as bulb food with a guaranteed analysis of 5-10-5, for example, with the first number being Nitrogen content, the second and most important for bulbs, being phosphorus content, and the third number being potassium content. The phosphorus is the most important nutrient for bulbs, and is high in bone meal or in a fertilizer labelled especially for bulbs.
I cannot really tell from the pictures whether the soil is wet or not, but daylilies and irises enjoy well-drained soil, not wet soil. This might explain why the ones nearer the sidewalk are doing better, if they perhaps dry out before the others. If the soil they are planted in is clay soil, make sure that, when you lift them to divide them, that you mix in some compost. This will improve the texture and drainage capability of the soil.