Star Anise comes from the Illcium verum tree, native to Southeast Asia. Often seen as an inexpensive substitute for true anise in cooking, the distinctive star shaped fruits contain the aroma molecule anethole, responsible for the anise flavor.
In gins, it can be hard to tell which type of anise you’re tasting. The effect is very similar, as both anise and star anise impart a “anise” like flavor.
Beyond the spirit and the juniper berries, you can feel free to experiment with whatever botanicals you like. Some of the most commonly used gin botanicals (after juniper) are coriander seed, angelica root, citrus peel and cassia bark or cinnamon – but feel free to raid the spice cabinet and herb garden. You could try bay leaves, rosemary, liquorice powder, lavender, cardamom, cumin, fennel seeds, lemongrass…pretty much anything you fancy!
Check out this link for some info on ratios and some recipe ideas. https://www.lovebrewing.co.uk/guides/gin-recipes-using-botanicals/