Some hacks:
1. Use M-O-O cheat for gazebos when it comes time to placing columns, so that they'll merge with whatever railing you've used as an edge.
2. Place two or more columns, create a roof trellis with super short railing (looks like a flowerbed border), then M-O-O to place heather over it to look like ivy.
3. If you want to make it look like petals have fallen around your bushes, use the painting tool to spot-paint terrain paint of the same flower around the base of plant. So, for example, say you put a bunch of purple hydrangea (?) bushes in your yard. Go to terrain paints, pick the paint with purple flowers and spray here and there. It looks better if you mix in with clover paint.