Bramble Stitch Finishing?

I’m trying to recreate a hat my grandmother bought me a couple years ago. The stitch I’m using is called a bramble stitch. It makes little bobbles. The stitch is a multiple of 4+1 and I’m at 90 stitches on my hat. Its to the point that I need to start decreasing to close up the top of the hat. Can some one please help me???

The decreases on this hat in trinity st (the same as bramble) seem to have solved the problem. See if these instructions help.