Sow some half hardy annuals such as Orlaya Grandiflora for bigger, earlier plants next year.
Daffodils can be planted now at twice the bulb's depth but wait till November/December for tulip planting to avoid the fungal disease Tulip Fire.
Sow some winter salad. I have tried 'Arctic King' and found it produces fine salad leaves in the Spring rather than winter.
If you want some new roses order bare rooted plants now.
Clear away the last remnants of summer flowering annuals.
Give your honeysuckle a final trim by late September.
Cover ponds with netting to stop leaves falling in.
Stop watering succulents and cacti but not Christmas cacti.
Stake Brussel Sprouts to prevent damage by winds