Continue fertilizing annuals and veggies for the remainder of the season. A 20-20-20 works fine.
Early season perennials can be cut back, such as veronica and roses. They should rebloom in a month or two.
Prop-up your tall-growing perennials with stakes, such as rudbeckias, coneflowers, hydrangea (with their heavy flowering heads), to prevent them from falling over.
Winter-hardy plants get their last fertilizer application before the fall. From here onward they will take care of themselves, stashing sugars into their roots.
If you've been keeping on top of weeding through June and July, you will find August not too bad. Stay on top of it.
Shop for new plants! As long as you water enough, planting in the heat of the summer is fine and by now, many of the garden centers are starting to discount their perennials and shrubs- you might just find a great deal!
Take care of your lawn. Fertilize your lawn with Iron Plus Lawn fertilizer. The results are incredible. Your lawn will be so green it will appear almost blue green.
Thicken your lawn. Mid-August is the best time to sow grass seed. Where thin spots exist, spread lawn soil 4 cm thick and rake smooth. Broadcast quality grass seed at the rate of 1kg per 100 sq. meters. Rake this smooth, step on it with a flat-soled shoes and water until germination.