Mother's Day is mere moments away, but don't panic if you haven't found the perfect gift yet. There's a very good chance your local grocery store, drug store, hardware store, or big box monstrosity/wonderland will have something that she'll love...
I think the key to all of these is in the presentation, so I recommend picking up a roll of brown craft paper and some twine— or another readily available combo that suits your aesthetic— while you're shopping.
Big Box store: I know I would love a gift box (which they conveniently sell) full of note cards, stickers, notepads, file folders, and $1 Spot treasures with which to gussy up my office/correspondence.
Home improvement store: A shrub! Pick out one that would suit her space (light level, available space, type of soil), with bonus points for sentimental reasons. I'm considering buying my mom a holly bush because her parents have a spectacular one on their farm and we decorate their house with holly boughs every winter. Offer to plant it for/with her, of course- not because she's a woman, but because it's fun to do nice things for/with your mom.
Grocery store: The grocery stores in our nearest small town are pretty lame, but I'd still be able to put together a fun gift box of unique hot sauces, interesting barbecue sauces, intriguing jams, strange mustards, and Italian breadsticks.
Drugstore: A selection of Essie nail polishes, which come in fantastic colors and last a crazy long time even when you're as haphazard at painting your nails as I am. Throw in one of those Nutella snack packs while you're at it.
Hardware store: My mom would love a collection of old-timey stuff that hardware stores always seem to keep in stock: Cloves and Black Jack gum, Cowtail candy, cool cleaning supplies in their adorable original packaging, hardcore hand salves, and any other awesome-looking tonics/potions.
Bookstore/Newsstand: My mom doesn't like to subscribe to magazines because she feels like they tend to repeat themselves issue-to-issue, but I think she would appreciate a nice fat stack of one-offs: National Geographic, Wired, Architectural Digest, Bon Appetit, and Audubon are all fascinating and beautifully produced. Bonus points if you can find some hard-to-find titles such as Chickpea, Elle Decor UK, Jamie, Tatler, or any of the cool international Vogues.