Ptaeroxylon obliquum aka Sneezewood

Ptaeroxylon obliquum has the common name sneezewood. It belongs to Rutaceae, the citrus family. It grows across southern Africa, as far as northeastern Tanzania. Its range takes in Angola, Namibia and Botswana. It also grows in Zimbabwe, Mozambique and South Africa. It lives in dry evergreen forest and bushland. In forests, it may share space with Podocarpus and Juniperus trees. It grows from sea level to 6,562 feet [2,000 metres].

Sneezewood forms a shrub or small to medium tree. It sheds its leaves in most cases. Reports put its usual height at 49–66 feet [15–20 metres]. Rare trees reach about 148 feet [45 metres]. The trunk often grows straight and is round across. Most trunks reach about 1.6 feet [0.5 metres] across. Rare trees have trunks nearly 4 feet [1.2 metres] wide. Its flowers make it useful as a tree for show.

The tree suits tropical and subtropical climates. It can also withstand frost of moderate strength. It grows best in soil formed from shale or limestone. It also grows in sand or rocky ground that drains well. Once it takes root, it can cope with drought. With good conditions, it gains 1.3–3.3 feet [0.4–1 metre] in height each year. It grows at a fairly fast rate. Cut stems can grow back, which lets growers use coppicing. Young trees also grow along forest edges. They can appear after a break in the leaf canopy.

People prize the wood because it is dense, hard and lasts well. The heartwood starts with a red tint. Exposure turns it orange-brown or golden brown. Pale grey sapwood forms a thin band at the edge. The wood feels fine and has a wavy grain. Its scent is like pepper. It resists termites, powderpost beetles and marine borers. People use wood chips to keep clothes moths away. They also use its resin to kill insects. These uses do not prove it resists all garden pests.

There are no known uses for food. In traditional medicine, people use the bark, wood, resin and twigs. They treat joint pain, headaches, heart complaints and urinary problems. These uses do not prove that home remedies work or are safe. The wood has oils that can cause strong irritation. Sawing or sanding frees dust that can cause severe sneezing. Growers can raise plants from seed or root suckers. Fresh seed sprouts well. Within a few months, though, it loses its power to sprout.