All my plants have started drooping and the leaves curling. Also started to go brown, stem as well. All plants in pots. Roses, lavender, etc.
Drooping Plants and Curling Leaves
When plants, especially plants in containers, are having problems, the first environmental condition to evaluate is soil moisture. Start with this article on watering plants in containers: https://www.gardeningknowhow.com/special/containers/container-plant-watering.htm
If nothing here seems applicable, you might be having trouble with insects or disease. You can contact the Master Gardeners to analyze samples and recommend treatment : http://mastergardeners.org.uk/get-involved/find-your-nearest-master-gardener/