This hardy citrus can be seen in flower in the Gilbert Carter Woodland.
A member of the rue family (Rutaceae) the genus Citrus contains approximately 25 species from south and south east Asia to northern China and Australia. Familiar members of the genus are oranges, lemons and limes, and Citrus trifoliata is a more unusual hardy member of the genus originating from China. It can reach 6m in height and has smooth, glossy, angular stems and rigid spines to 5cm. This is an evergreen species whose leaves are trifoliate, with three, though occasionally five, leaflets, and which have winged leaf stems. Highly scented white flowers are produced in spring and summer, and these may produce small, downy, fruits to 4cm in diameter, which will ripen to orange. The fruits are edible, though are incredibly bitter, giving rise to the common name bitter orange, though these can be made into a preserve with the addition of plenty of sugar.