beckygardener said:When daylilies are labeled as early, mid, and late bloomers ... how does that work? Is that time frame for a certain region of the country (such as where the hybridizer lives) or is that across the country no matter where they are growing? If so, are those "consistent" bloom times? Or are those also affected by heat and cold regarding bloom times during the growing season? If we have an early Spring/Summer or those up North have a late Spring/Summer due to weather temps, that affects how quickly they will bloom? Does that also affect rebloom?
The simple answer is that the registered information for bloom season is for the hybridizer's location and growing conditions.
The biological factors that affect a daylily's bloom season are complex and we do not know enough about them.
I will begin as simply as possible and then add some of the possible complications.
Lets begin with ten seeds, one from each of ten different crosses planted in optimum conditions with no changes from day to day (ie no weather, in a lab or growing room where everything is controlled). After a certain number of days each plant would bloom and then they would bloom again after another number of days and then they would bloom again after another number of days, etc. for as long as we grew the plants. We would expect that each plant would have its own different number of days between bloom periods. Because the first bloom period the plant grew from a seed and for all other bloom periods the plant grew from its own crown the first bloom time might or might not be the same as the rest of the bloom times. As long as the growing conditions were consistent we would expect that the bloom times (number of days between say the end of one flowering to the beginning of the next flowering) would also be consistent (no seeds being set). Some plants would take fewer days to the next bloom cycle while other plants would take longer. That would be because the plants are genetically different - their genotypes are different.
Now lets say we change the growing conditions. We still keep them consistent but they are different from the first test. Perhaps in the first test we set the temperature to be 75F and kept the lights on for 18 hours each day and perhaps in the second test we lower the temperature to 68F and keep the lights on for only 16 hours each day. We would begin by expecting that although the number of days between bloom cycles would change, that the order of the different plants would remain the same - those that took longer would still take longer, etc. However living things often do not do what we expect of them. If there is genotype X environment interaction then the order of bloom cycles for the different plants may change when we change the (growing) environment. It would not necessarily change for all the plants but it might for some of them.
In a garden we have other complications. There will be locations where, by definition, the growing season is classified as being 12 months long. There may be daylily cultivars that can grow all year round in those locations. In those cases what do we use as the start of the growing season for those cultivars to be able to classify their bloom times as early, mid or late, for example?
The weather will affect bloom times because a daylily has to grow and develop its scape and its flowers. Early and late springs will affect bloom dates. Warm versus cool growing season temperatures will affect rebloom dates or whether rebloom occurs at all.
Just as there could be genotype X environment interaction under controlled conditions there could be genotype X environment interaction in natural conditions between different gardens in different locations. We would begin with the prediction or expectation that the order of first flower open (FFO) would remain the same for different cultivars in different locations but they might not (due to genotype x environment interaction). A complication with FFO dates is that for any cultivar they become earlier the more scapes are produced - the more flowers there are to open (to a limit, more or less).
