RobinSeeds said:Wow, thanks for all of that info Maurice
You are very welcome
If I understand this correctly, the only way to find out definitively if a cultivar is to be registered as "evergreen" would be to continually strip the leaves away and/or dig up to view the crown for the purpose of observing a failure to set a bud (unless I am mistaken).
Unfortunately, if you remove leaves continually you will probably change the behaviour of the plant.
To be 100% certain of whether a bud has been set you do have to dig up the crown and carefully strip away leaves checking for signs of a bud or not.
However, you can get a reasonable idea of whether a bud may have been set by watching the behaviour of new leaves and keeping an eye on the temperature.
Let's assume that you have planted a single fan daylily. Right beside the centre of the fan you place say a small two inch tall block of wood. Every week (or few days) you look to see whether a new baby leaf appears in the centre of the fan and when the tip of that leaf manages to become just barely taller than the top of the block you record the date. You keep watching and when the next baby leaf manages to become just barely taller than the top of the block you record the date. You keep doing that until you notice that no new baby leaf has appeared for say three weeks. You check the temperatures over those three weeks and they are not much different than the previous few weeks temperatures when new leaves were appearing regularly.
The job of the growing point is to produce new leaves when it is not a dormant bud. It does not really matter that those leaves may grow (become longer) faster at warm temperatures and may grow slower at cool temperatures. When the growing point is able to produce new baby leaves it is not dormant (stopped producing new leaves) as long as the temperatures are high enough for the plant to grow.
Lets say the daily average temperatures have stayed about 75F for three weeks and during that time new leaves appeared above the block once every 5 days. Then the temperatures remained the same but no new leaf appeared in the last three weeks. It is likely that the growing point had become a dormant bud (stopped producing new baby leaves). We might simply assume that it was then dormant.
OR We could then dig up the crown and strip any leaves away carefully one by one until we could see if it looked as if a (closed tip) bud had formed at the crown.
If there is a bud present and we want to know how that bud will behave, after removing all the leaves we can replant the crown and give it good growing conditions. If the daylily resprouts new leaves within a couple of weeks then the bud was only temporarily resting. If the bud does not sprout for many weeks to months then the bud was in a more permanent resting period (dormant).
Researchers might have potted say 15 crowns each in its own pot. They then would bring say five pots inside on Novermber 1, remove all visible leaves and give the pots good growing conditions. They would watch and record how long it takes for the plants to sprout new leaves (calculate the average time). They would bring another five pots inside on December 1 and treat them the same way and they might bring the last five pots inside on January 1. If the plants sprout quickly then they are not dormant if they take many weeks or months to sprout then they are dormant. They could learn when the plants were dormant and if they were dormant at some time, how long they stayed dormant. To do a complete study they might require many more than 15 plants and bring them inside at more times.
