Licorice root can help to regulate blood pressure; because it is an adaptogen. That means it can help to balance it whether high or low. Adaptogens do this by strengthening the adrenal glands, which help to regulate blood pressure.
Earlybird, what you might have seen is that licorice root is often listed as raising blood pressure, but it takes about 50 grams daily over 6 months to raise blood pressure. That is a massive amount. And this effect can be countered with potassium supplementation. If you are taking Prednisone, you should not take any licorice root. It prolongs the effects of Prednisone and will definitely raise the blood pressure. They do this by decreasing potassium levels and by causing sodium retention.