Plants just become white above F0 stars so, plants around an A or an O star won't look much different. Not that there will be plants on those planets as A stars and above do not live long enough for multicellular life to arise. Especially B and O stars as they might not live long enough for life at all. As for multiple stars, the answer is well, who knows but, plant life probably adapts to the star that is giving the planet the most light for the most part.
Again, the reason I didn't include white plants is because no stars that are above F5V support multicellular plant life (in SE) and the fact the white plants mess with the material system in SE and I haven't figured out a workaround yet.
CPU: Intel Core i7-4790K
GPU: Nvidia GTX 1080
SSD: Samsung 850 Evo 250GB
HDD: Toshiba DT01ACA200 2TB
HDD: WD Blue 1TB (2012)
RAM: Unknown 16G-D3-1600-MR 2x8GB
MBD: MSI Z97S SLI Krait Edition (MS-7922)