Sedum is an hard-wearing plant, if there is no water stagnation, excessive fertilization or irrigation, it does not have particular problems.
Sedum, however, might suffer from stress when night temperatures remain above 20° C and in the presence of a level of relative humidity higher than 70-80%. These conditions are found especially in the Po valley during summer and might favour the development of fungal diseases, which might require interventions with agrochemicals. It should also be noted that the philosophy of a garden or a green roof made with Sedum involves a natural, rustic approach, linked to the dynamism of this type of plant.
The species of Sedum have differences of growth, flowering, and colours that change throughout the seasons and according to the climate. If, for some reason, the Sedum in certain conditions were to regress, you will only have to cut some leaves as soon as the weather gets better, and arrange them where you can see some thinning. These leaves will work as scions that you will need to spread as seeds. The scions of Sedum take roots easily.