Marketing tools as Mother's Day gifts isn't something you see every day. But why not? If hardware stores can do it with screw drivers and hammers, then you can certainly do it with gardening tools.
People come in droves to your store Mother's Day weekend to buy flowers for Mom, so why not capture some add-on sales by dedicating a prominent display in your store to "Gardening Tools For Mom"? There are plenty of companies out there offering gardening tools and gloves designed specially for women, including pink tools for breast cancer awareness, ergonomic tools to fit a woman's hand, gloves created to be comfortable for women and much more.
And I definitely think a nice trowel and some gardening gloves will be an easier sell than a hammer and nails.