The root of this plant is popularly used by most gin distillers either with orris root or by itself, for its fixative properties.
The taste of the gin with this botanical is earthy and herbal. The root of angelica is used to fix a wide range of volatile flavors. The combination of these gin botanicals brings a very harmonious and blended taste to the final gin – which without angelica would taste quite rough.
Usage 0.5g to 1g/litre. As an essential fixative start with 1/10th the amount of angelica to juniper.
Check out this link for some info on ratios and some recipe ideas.