Could you direct me to a good video to help me teach my 7th-grade students about sexual and asexual reproduction in plants?
Take a look at this NOVA production -- an online streaming video, with permission to show in classrooms,
I searched for more videos on this website using the search "plants reproduction" and found several more that may be of interest.
See also the supporting material and additional clips, and note that you can filter your search by grade and format (videos).
Hope this helps!