Hawthorn berries, leaves and flowers for Hyper or Hypo tension

Hello,

How to explain contradictory when reading about hawthorn.
One view says that is sutiable for Hypertension, dilates blood vessels. On the other side it supposed to be remedy for lower blood pressure, act as astrindgen ( shorten tissues )...

As I read there are two forms of ingestion hawthorn:
a) as berries
b) leaves and flowers