Rubus fruticosus Merton Thornless Thorn free and compact growth A popular variety that is easy to manage, as the name implies it is a thornless blackberry. The succulent clusters of fruits ripen in early autumn and are perfect for jams, jellies, pies and crumbles. Where? Best in sun or part shade. How? Happy in any fertile, well-drained soil. Add homemade garden compost or well rotted manure to the soil before planting. Plant against a wall or fence and tie in the stems as they grow