How can I tell if plants are long- or short-day?
I'm performing a research to see if artificial light from street lamps affects the growth and shedding of plant leaves.
In order for me to discuss my results I have to know if these plants are long-day or short-day plants.
The way I understand it from having researched, my plants are long-day plants as they are blooming in the spring when there is more than ~6hrs of sun per day.
But is bloom time only when actual flowers bloom or can it be when the leaves sprout? The way I see it it's when the plants comes out of dormancy, whether that be in the spring or in the fall. But trees such as a few varieties of Oak defy this as their flowers grow prior to their leaves. It really confuses me as to what can be called long-day plant.
The plants in question are:
Species 1. Lilac - Syringa vulgaris.
s.2. Cherry - Prunus avium
s.3. Maple - Crimson King
s.8 London Plane
s.10 Hawthorn - Crataegus sp.
s.12 Willow - Salix sp.