An unusual shrub, native to South America, Colletia armata has branches covered in a multitude of thorns – actually modified leaves. It flowers in late summer and early autumn, bearing a profusion of waxy white, lightly-scented flowers. These are very attractive to bees and other pollinators. The plant is slow-growing but will reach an eventual height of around three metres and spread out to cover about the same horizontal distance. It likes a sheltered spot on well-drained, moist soil. It should be planted in sun or partial shade and given room to grow as a specimen plant. It is generally free of pests and diseases and does not need pruning. You can see it growing in the University Parks near the Lady Margaret Hall gate, which is along North Walk.