Things to do in the garden in August
Harvesting all those crops you have been growing (and freezing and making lots of soup, jam etc to use the surpluses ) and deadheading to keep the flower garden going are the main things to do this month.
Deadheading
For a continuous supply of flowers keep deadheading. Annual bedding plants such as petunias need weekly deadheading to encourage further flowering. I deadhead my dahlias once or twice a week (usually when I am cutting a fresh supply for displays in the house) and my dahlias have been flowering continuously for a good 3 months or more now. I reallly could not have too many dahlias in my garden and am already looking forward to perusing the catelogues in the winter to choose my next purchases.
Watering
Living in the south of France I avoid buying plants which cannot cope with a bit of drought but non-the-less there are always plants or trees in their first year which need help to get through their first summer. Water little but often and in the evening so that plants get the most benefit from the water and are encouraged to grow a deep healthy root system. And mulch.
Mulching
Keep repleneshing mulch if it gets too thin. Organic mulches are permanently being broken down, which is great for the soil and the plants but means the mulch needs to be topped up from time to time.
Rose care
Keep checking for problems and spray if necessary.
Deadhead regularly to get more flowers
In the Potager (Kitchen Garden)
Harvest crops, especially those like beans which need picking to ensure more grow
Sow spring cabbage, turnips, lettuce, rocket, radish, chicory and parsley
Wildlife
Keep birdbaths topped up with fresh water and wash the bath from time to time.