If the plate was made by Challinor, it would be from the 1850's. Two other potters made a Rock pattern, but they were in 1820's and 1830's, before flow blue. If it is Challinor, the pattern has large peonies around the border and the lower right center is a very large peony and a prunus branch which rises and circles up and left over temples and fences. Hope this helps.
Kim and Judy