Celtis overview

Celtis are members of the ULMACEAE family. There are over 150 species about six being indigenous to South Africa. As a bonsai grower I have had dealings with three varieties - Celtis africana, C.australis and C.sinensis.

1. Celtis Africana - Camdeboo stinkwood, African elm, or white stinkwood, is found from the Cape Peninsula to Ethiopia and grows under a great varriety of conditions, from forests and river banks to bare koppies. The tree can reach a height of 30m in nature, is deciduous or evergreen, withstands drought and frost; is a moderately fast grower and has smooth grey bark. The leaves are simple, alternate ovate to elliptical, serrated towards the apex. They can be smooth or furry, are beautifully soft green in spring, dark green in summer and yellow in autumn. Flowers are insignificant, fruit yellow. Celtis africana is not valued for its timber but ideal for shade and for ornamental trees in streets parks and gardens.
2. Celtis Australis - Nettle tree, is found in Southern Europe, North Africa and the Himalayan regions. It is shorter, slower growing and with larger leaves than the C.africana. The fruit is black.
3. Celtis Sinensis - Chinese hackberry or Chinese nettle, is found in China, Taiwan and Japan. It is faster growing than C.australis, the leaves wider and darker, the fruit orange and it can be used for fodder.

Celtis as Bonsai

They are suitable for most of our styles, ego forests, root over rock, slab planting, informal, broom style, leaning trunk. Because of the delicacy of their leaves and lacy branchlets, they lend themselves to the softer styles.

Celtis like a cool spot, protected from the wind. If they are subjected to a combination of wind and drought, the leaves will turn brown around the edges. If conditions are really severe the tree might defoliate completely, so if you are to keep that beautiful crop of soft green leaves looking at its best right through summer, you will have to take a little care in selecting a good position for your tree, also with your feeding and repotting programme.

A regular once a fortnight feeding with a well balanced fertiliser, 2-3-2 is recommended throughout spring and summer to keep your tree looking at its best. Seagro and LAN can be used occasionally. With well-fed and well protected trees, die back is kept to a minimum.

Potting should be done as new buds burst, usually the end of July or beginning of August. One third each of loam, leaf mold and course river sand constitutes a good potting mixture, which should be used with the addition of bone meal or osmocote.

Snails adore Celtis and can defoliate a small tree overnight. A few snail pellets will solve that problem. Red spider or black spot can be a problem but insecticide sometimes causes the tree to drop its leaves so rather than do permanent damage, defoliate the tree yourself. They are prone to scale which can cause loss of complete branches if not dealt with.