Despite its pretty spring flowers and its summer fruits, the horsewood is known more for the smell associated with its crushed leaves than for its attractive appearance. In South Africa it is commonly referred to by its Afrikaans name, perdepis, which literally means ‘horse piss’.
Its botanical name Clausena anisate also refers to the smell exuded by leaves that have been bruised or crushed, with anisate meaning anise or aniseed. In actual fact the smell of the leaves is not consistent across all regions, and the smell is variably described as being, for example, pungent, like horse urine, like lemon or like aniseed. And people respond to the smell differently too, with some finding it unpleasant and others not.
I don’t find the smell of the leaves on our tree unpleasant at all. I have just been outside and crushed some leaves in my hand and the smell is a kind of generalised citrusy smell, which is not surprising as the horsewood is a member of the citrus family, Rutaceae. I could not detect anything resembling aniseed, but in some regions the leaves are used to flavour curries.
Irrespective of the smell of the leaves, vervet monkeys and some birds seek out the horsewood fruit. The above photo I took from our back deck of two vervet monkeys enjoying the fruits. The large tree trunk belongs to a pigeon wood tree (Trema orientalis) and the slender horsewood is growing up around it.
In the spring the delicate white flowers of the horsewood cluster among new leaves at the ends of willowy branches
The small flowers have a subtle sweet scent and attract many insects. The tree is one of the larval host plants of many of the swallowtail butterflies, but unfortunately I have not managed to get a usable photo of these butterflies flitting in and out among the leaves.
The horsewood occurs naturally in regions with relatively high rainfall and is associated with forest margins and densely vegetated areas. It is found over most of sub-Saharan Africa (but not in the arid regions) and it also occurs in India and much of South-East Asia.
Essential oils in the leaves, seeds, fruits, roots and bark contain several identified chemicals and concentrations of these chemicals within the oils vary across plants from different regions. Medicines derived from different parts of the plant are used extensively in traditional medicine, and ongoing research shows that beneficial medicinal attributes include antibacterial, antifungal and antioxidant properties. Some preparations are also effective as repellents against certain insects.
The branches and stems of the small horsewood tree that is growing in amongst some other trees on the edge of our garden are also attractive. The wood is heavy and hard and is used in hut building and the thinner stems are used to make walking sticks. Twigs, with their antiseptic properties, are used as toothbrushes.
In the early summer, small fruits about the size of grapes start off green in colour and darken through purple to almost black. Interestingly, vervet monkeys enjoy eating them while they are still green, although birds seem to prefer the ripened fruit.
A rather soulful mother monkey, nursing a baby that is just visible, perches on the convenient trunk of the pigeon wood tree as she picks some green fruits from the horsewood.
The mother released her young baby who managed to clamber about rather awkwardly to pick and eat green fruit
At another time this big fella also made use of the pigeon wood trunk as a perch while picking and eating horsewood fruit
Fruits of different degrees of ripeness hang in clusters on our horsewood tree
Unfortunately the recent hailstorm took place at peak fruiting time and knocked off most of the fruits before they had a chance to ripen, so pickings have been very thin this year. It was only reading for this post that I discovered that the slightly sweet fruits are edible for humans too. I will try them next season.
The birds move so quickly when foraging for fruit so this is the best I managed to do when photographing Cape white-eyes selecting the ripest fruit to eat in the horsewood tree
The horsewood is deciduous in regions that have a long dry season, and that is the case here. It is a lovely tree, well suited to a spot in shade or semi-shade in a small garden, and great for attracting a variety of birds and pollinating insects, as well as hosting swallow-tailed butterflies that lay their eggs on the leaves.
Boon, Richard. 2010 (2nd ed.). Pooley’s Trees of Eastern South Africa. Durban: Flora & Fauna; Tchinda, A.T., 2011. Clausena anisata (Willd.) Hook.f. ex Benth. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. https://uses.plantnet-project.org/en/Clausena_anisata_(PROTA); Tropical Plants Database, Ken Fern. tropical.theferns.info. http://tropical.theferns.info/viewtropical.php?id=Clausena+anisata
Posted by Carol