Q: Can you prune Fatsia japonica plants, and if so, when is a good time and how much should you prune? DB, Co Galway
A: Commonly known as the false castor oil plant or as Japanese aralia, this majestic shrub is grown for its dramatic, glossy evergreen foliage as well as its large ‘candles’ of creamy white flowers which appear in autumn and are followed by black berries.
Variegated varieties are also available including the prettily-named but less hardy and slower-growing, Fatsia ‘Spiders Web’ (or Fatsia ‘Tsumugi-shibori’), with leaves that are deeply edged and streaked with white, and the cream-edged Fatsia japonica ‘Variegata’.
Its giant palmate leaves make this stately species a great choice for a lightly shaded, sheltered, tropical-style border or exotic town garden, where it looks right at home alongside other handsome foliage plants, including clumping bamboos, hardy palms, tree ferns, hostas and ornamental grasses.
It also makes a great indoor, container-grown houseplant, as long as it’s given plenty of space in a coolish room.
Left to its own devices, Fatsia japonica can eventually become a very sizeable, spreading plant capable of reaching a height and spread of four metres or more.
Although it is hardy, those giant leaves can also become tatty over time, especially if the plant is exposed to cold, drying winds or very harsh winter frosts. For this reason, it is a good idea to remove any badly damaged leaves in late spring.
Any pruning should also be carried out in late spring, taking care to do so in a way that preserves its graceful growth habit and statuesque silhouette. For best results, select only the oldest stems, cutting up to a third of the plant’s stems right back down to their base
