Posted: 29/09/2017 at 13:47
When the plants are dormant so after leaf fall but whilst the soil is still warm enough for the roots to recover and grow out into their new home, ready to support the spring burst of growth.
Water the plants well to reduce root disturbance and dig them up with as much root ball as you can carry after they've had a chance to soak it up. Re-plant immediately in prepared planting holes with added well-rotted garden compost or manure and a sprinkling of bonemeal which promotes roots. Microrhyzal fungae scattered on the root ball will also help.
Vanille Fraise is a paniculata form of hydrangea and will be happiest in the ground. Too easy to stress it in a pot with lack of moisture, lack of space, lack of nutrients. They can be pruned back hard in spring so you can control size and shape that way.
Perennials such as osteospermums and cannas can't take frosts so need to be sheltered over winter. Again, dig up and re-plant or pot up in autumn.
Autumn is also the best time to move other perennials such as achillea and penstemons but not the late flowering rudbeckias, asters etc. They're best done in spring. Penstemons are hardy but to varying degrees. Usually, the broader leaved forms are more tender than the finer leaved.