Damsons are often picked in midsummer when they are ripe and ready for picking. As you can see from the picture below, damsons ripen on the tree over a period of 4-5 weeks. From July to August is best as this is when there is little chance of frost or frost damage. Picking them while they are still young will result in larger fruit size but once they have started maturing, picking later than mid-August results in smaller fruit which do not store well due to their susceptibility to “off” flavours (frost). If left until September, then it’s too late for them!