Ochna is a genus of about 85 species of evergreen trees, shrubs, and shrublets that belong to the family Ochnaceae. These types of plants are endemic to the tropical woodlands of southern Africa and Asia and are now being cultivated in North America and Oceania. The shrubs usually measure 5 feet (1.5 m) tall but can reach up to 10 feet (3 m) in height. Ochna species are generally referred to as mickey-mouse plants due to the shape of their drupaceous fruit.
The leaves of these plants are oblong and dark green with finely toothed margins and brown stems. Their flowers have five bright yellow petals with green sepals below. The sepals remain even after the fruit has been formed, enlarging as the flowers age before finally turning fleshy and red. Round and glossy green when first formed, the fruit eventually turns black when it becomes ripe.
Widely cultivated as decorative plants, they can be planted in pots as indoor plants or planted in flowerbeds in outdoor gardens. Once established, Ochna plants can even be guided to form hedges. Perhaps the most popular species is the Ochna serrulata, or bird’s eye plant. Other species cultivated for the same purpose are the O. mossambicensis, O. thomasiana, and O. jabotapita.
These evergreen plants are easy to grow. They thrive in light shade and mildly acidic to acidic soil. Only little to moderate water is required, and they are even found to be tolerant to drought. Attractive to bees and butterflies, the flowers bloom in late spring and early summer. Once their fruits are formed, they are usually eaten up right away by birds, which also act as a natural propagator as they scatter the seeds around through their droppings.
Despite, or maybe even because of, being a popular ornamental plant, these plants have a tendency to be invasive, as the seeds can be easily spread. Aside from that, their capability to form into dense thickets when established may block other plant species from regenerating naturally in the wild. Introduced from Africa during the early 1900s, these plants are already treated as weeds in eastern Australia. Ochna serrulata in particular has invaded bare areas of riparian habitat in the southeastern part of Queensland and has also been declared as noxious in New South Wales. Weed control measures employed include applying glyphosate on a scraped off portion of the bark for established plants or just pulling the plant out by hand for young seedlings.