A very important part of whether a cultivar reblooms or not is how it is being grown as well as where.
If it is in a large clump it will be less likely to rebloom: I think that the size of the clump is an important factor on whether a cultivar reblooms. The more fans in a clump the more of every resource that each fan must share with the other fans. That includes water, sunlight (because of shading by neighbouring fans), fertilizer, etc..
If it is not fertilized it will be less likely to rebloom. To rebloom a fan needs to grow and to grow as quickly as it can. To do that it needs sufficient fertilizer along with water and all the other resources. The growth of plants is often limited by insufficient nitrogen. So sufficient or optimum nitrogen fertilizing is important for rebloom.
Because daylilies are perennials it is also likely that how the plant is being grown this season is not as important as how it was grown last season and possibly even the season before. So it may take one or two (or possibly even more) years of a changed growing condition before the growth and flowering of the daylily is changed. Patience and perseverance are necessary after changing a daylilies growing conditions.
