In my garden there are a handful of lilac shrubs (sering in Dutch) and they appear to be two species and one cultivar. The one in the first photo appears to be Syringa vulgaris, of which we have also a rather ugly mildew-susceptible double flower cultivar in a nice burgundy colour. Then we have Syringa meyeri, a smaller, rounded shrub with delightful little round leaves #plants#plantidentification
