Can there be any natural (holistic) supplements I can use to help lower my blood pressure?

NO. Blood pressure is a silent killer do not trust holistic medicine if you have high BP and there are good safe medications to take reduction of weight and lowering the salt intake can be useful if the blood pressure is only slightly raised.
Lifestyle Changes. I agree that you must not let BP run high due to end organ damage that can occur. However, there are many lifestyle changes such as a paleo-mediterranean diet, daily exercise (including relaxation exercise such as deep breathing, prayer, meditation), and 5-10% weight loss if overweight. Stress causes production of cortisol & Epinephrine which may raise BP so controlling stressors is also key!