September "is a great time to be going into your nurseries and looking for good prices on shrubs and trees," Smith says. "I've seen sales as deep as 50 percent."
September sales on plants especially make sense this year because a lot of homeowners lost vegetation to the summer heat.
Another garden-related item where you'll find good buys on Labor Day and beyond is canning supplies. While a lot of home gardeners have wrapped it up for the year, farmers markets "are going to be full of fresh vegetables well into November," Smith says.
But many retailers won't keep pressure cookers, jars and other supplies on the shelves past August, says Smith. As a result, you could save as much as 50 percent on those supplies in September.