The active ingredient in root stimulators is: indole-3-butyric acid. It's synthetic, but is preferred over the natural plant growth regulators because it doesn't break down as quickly.

Be aware that you can't stimulate plants to do everything at once. They're a bit attention deficitted. If you want roots, you may postpone foliage and blooms; vice versa. But when roots are your priority, go for the rooting hormone. I apply it directly to what roots remain, but foliar spraying may also be effective. I'd research how the chemicals are taken up to be sure.

McJulie