I wasn’t able to resize foliage I had already placed, but you can control the scale for any new foliage by using this option:
- Select your foliage asset in the Foliage tool.
- Adjust the Scale X before placing new foliage.
I recommend setting a maximum scale of 0.3 and a minimum of 0.1
Again, I couldn’t find a way to resize foliage that was already placed.
If you don’t see this option, please share a screenshot of your Foliage tool panel so I can help further.