Help with iMovie on my phone?

When I film something on iMovie, all the small clips get put on my camera roll, this is taking up a lot of space on my phone, but if I delete the videos the videos in iMovie delete as well. Is there any way to not have them on my camera roll but still have the iMovie working
Answers

AlCapone

Store your videos on Google Photo. The app for your phone is free and storage is free, up to a large limit. However, you'll have to keep the clips that you are actually using for a movie on your phone until you complete and save that movie. Then you can delete them, assuming you have them backed up on Google Photos first.

SRΛSC

No. iMovie gets the media from the Camera Roll. You could place them in iCloud storage until you are ready to do whatever or you could do whatever with them to clear them out faster.

Mmm J

Store the video clips outside of the phone - like iCloud. Lots of video storage will require a subscription fee.