Cutting back dahlias in autumn to prepare them for winter, and adding mulch, as a Robin watches!

Dahlias - beautiful flowers in a rainbow of colours through summer months, but what do you do in autumn / fall to help protect them over the colder months of winter ..?
*Watch out for a special guest appearance of a cheeky re breasted Robin during this video ...

Roger shows us what he does every year in the school garden with his group of Dahila 'Rebecca's world' (The flowers on this variety are a mixture of deep pink / maroon red / and white - all at the same time)
- cutting back all the stems to just above ground level
- leaving the tubers in the ground (* see note of cation about this below)
- spreading a layer of fallen tree leaves over the soil around the roots as a mulch to provide warm and protection to the roots / tubers

* Dahlias are not frost hardy, and the roots / tubers could be killed by extreme frost. So the safest way to protect your Dahlia tubers might be to dig them up after cutting back in the autumn / fall ... it depends on how could your winter are.
Here in south wales we do get winter frosts, but for the last 20 years it has rarely gone below - 6 Celsius, and our patch of Dahlias which are on a well drained patch of ground have survived the short cold snaps with the help of some mulch on the soil surface.
(If you your soil is not well drained and gets very damp over winter that could increase the risk of frost damage, also tender younger plants may be more easily damaged by frost - our patch of Dahlias have been in the ground for several years and winters)

Mulch - you can use many different materials as a mulch - such as straw, compost, and leaves.