Cloned lilac phenophase issues

[alte...@whitman.edu]

Hello!

I have one of the cloned lilacs and want to contribute meaningful phenological observations, but I am having trouble figuring out two of the phenophases.

1. ok

2. "Do you see all leaf buds broken?" The given explanation for this question says that you wait until virtually all of the of actively growing leaf buds (95-100%) have emerged. I have trouble with "actively growing." I continually see leaf buds (yes, over 5%) on the shrub that may or mat not be "actively growing," so I have no clear transition to date on the phenophase data. 

3. "Do you see open flowers?" Here the question explanation speaks of when at least half of the flower clusters have at least one open flower. My problem here is the scale of "flower cluster" on a complex inflorescence like this. A flower cluster could be a tiny twig's cluster of 5, 10 or 20 flowers (depending on how many branches you include), or the entire complex branched inflorescence at the end of a large shoot. Which is it?

I would love some advice. Thank you, -Susanne

[Ellen Denny]

Hi Susanne,

The phenophase definitions for the lilacs are from an historical protocol dating back several decades and are a bit different than for all the other Nature's Notebook species, and perhaps a bit more awkward. 

For #2 above, "All leaf buds broken" is meant to capture the point at which all the existing leaf buds have already broken and there will be no more new ones breaking for the rest of the growing season. This generally occurs when there are a lot of leaves on the plant, but before they get to be full size. If at that point you are still seeing unbroken leaf buds that are not at least getting larger in size as they swell before breaking, then those buds are probably essentially "dead" and you can ignore them. 

For #3 above, "flower cluster" refers to the entire conical/cylindrical inflorescence.

Hope this helps!