Why are my dogwood (Korean) and iris blooming now in southern Oregon?

Answer 1

The photoperiod now is the same as it is in the spring when they bloom. The length of light and darkness and length of light determine when these plant bloom. Nature is fooling them right now because in the spring you have days and nights about equal (12 hr each). So they bloom. In the summer the days are too long so they don't bloom. But as fall comes the days shorten until the day and night are about 12 hr each again. Usually the temp and other factors keep them from blooming twice in a year but if everything is right and the days and nights are 12 hours each the plants think it's spring and bloom again. Of course, they don't really think--it's all chemical.

Answer 2

I agree whole heartedly with Collegekid. The temperature and amount of daylight have mixed together in just the right amounts to resemble spring. Because those plants set their flower buds (or in the case of the iris, inside the rhizome) in the summer for the following spring... they're all ready. And nature fooled them.

Magnolia is also easily fooled this time of year.

Good luck-