Use the appropriate size punch for your particular flower scale to cut heart shapes from thin dark green paper for your morning glory vines. The most realistic leaves will be made from dark green painted paper, with a slight gloss finish.
To make leaves for tiny 1:48 scale morning glory vines, fold a thin strip of green paper in half lengthwise and use sharp curved scissors to cut half hearts on the fold. Carefully set your cut or punched hearts on a piece of craft foam, a foam mousepad, or an eraser, and use an embossing tool to draw a line down the center of the heart to form a leaf vein.
In the photo on this page you can see the hearts being punched from a thick piece of green paper which has been split and opened to make a thinner layer of paper more suitable for 1:24 scale leaves.