Make the rose of the bottom of the wedding bouquet the length you want the cascade to be. It will be longer than the other rose stems and you can leave the rose leaves attached if you wish.
Insert the bottom rose straight up into the bouquet holder. Then continue to cut stems to match the roses on the opposite side and insert them on the left of the bouquet.
Now I cut a rose almost as long as the bottom cascade flower for filling out the cascade portion.
I'm inserting this flower angled upwards and left to the center rose.
This flower extends outward a bit (this is where the extra length is needed).
From the side angle, you can see that this bridal bouquet has depth and dimension - it doesn't have a "flat" look.
Here's a left lateral view. Can you already spot more places that I'll be inserting more roses?