I visited T.J. Maxx's outdoorsy sibling Sierra, one of the fastest-growing brands in the retailer's family

I wasn't sure what to expect the first time I visited Sierra, but now I'm hooked. Dominick Reuter/Business Insider Sierra is TJX's outdoor lifestyle brand, selling apparel, gear, home goods, and pet products. It's still relatively small, but TJX said the chain could grow to 325 locations. Business…