I noticed most of my red tulips are not as red as before and wondering if I should do anything at all or let it be. Fertilizing/ digging out once every 2 or 3 years? I noticed totally yellow one which I do not remember I had, but could be one that never bloomed before, but the rest...

Last year





And this year





The last batch is actually more red than the ones that came earlier, so I wonder if it is related to abnormal weather and they will be fine in the future...