Change in daylilies over a few years
I planted a row of daylilies about 7 years ago now. I swear I had about 4 different varieties planted! But now they are all the same color (kind of an apricot shade) although they do retain two shapes (one classic and the other the ruffled type). Could pollination of plants close to each other actually change the roots and overall appearance after several years?
Ramsey County Minnesota
Here is my best guess as to what is occurring. I say this from my own genetics background and gardening experience. Day lilies of different colors, such as you presumably first planted, are the result of extensive breeding. The “original” daylily had flowers that were yellow, tending towards the apricot color that you are now observing. Although day lilies are generally self-pollinating, they can also cross pollinate. Regardless of which happens, seeds from such pollination can be produced and fall to the ground. Some of these seeds will produce yellow flowers and typically will be very vigorous growers. Reports exist that over time, these yellow colored day lilies will predominate. There really is no way to prevent this from happening. If you want to change things, it probably would involve digging things up and planting anew.
Here is a University of Minnesota publication giving general information about daylilies: