If you feel the need to carry a large scary-looking blade, you can get a gardening machete for $20-$60 off Amazon. The folks who made your mom's good scissors also make this Klingon-lookin' thing.

(On the other hand, if you're carrying gardening equipment to look scary, either a gasoline-powered hedge-trimmer or a mattock could be even more effective than the machete. Unless you are actually Danny Trejo.)