There are a lot of natural methods but they are very unpredictable. The best thing you can do is follow all the lifestyle and diet recommendations. Those are basics. After that, without doubt the most powerful natural method to lower blood pressure is slow breathing. There is a new method called Breatheasy that is a genuine alternative to expensive biofeedback gadgets. It's easy and enjoyable and takes just 15 minutes a day. Slow breathing is so good because it also relaxes you and relieves stress and anxiety and can even help you sleep.
Yoga is well known for helping to lower blood pressure but Breatheasy streamlines the technique and helps you learn it very quickly.
It's the only thing that helps me control my blood pressure and I've been able to avoid medication with it.