Grafting euphorbias is of interest for several rare and difficult species as when they are on more vigorous easier stocks, they are easier to keep, grow faster and produce more flowers and seeds.
The method of grafting euphorbias differs little from that of other succulents, except in one important aspect. The latex must be washed or sprayed off until hardly anything remains. After the latex flow has stopped, a further 1-2 mm slice can be taken from both surfaces without a new latex flow starting.
Both plants need to be at the start of the growing season. The stock should be cut as near as possible to the growing tip, as here the vascular bundles are dense and not yet woody and will feed the scion in the best possible way. Where possible stock and scion should be of similar diameter. The cut surfaces are held together with elastic bands in cross style, over the plant top and under the pot. The plants should be left in an airy and shady place for 7-10 days before the bands are removed.
Almost all euphorbias are suitable as stock, but it should be remembered that especially strong stocks may change the appearance of the scion. At the same time, however, they may also increase the chances of flowering or branching, which is a positive effect for rare and difficult species.
Strong growing stocks are E. ingens, E. candelabrum, E. canariensis, E. grandicornis and E. trigona. A moderately strong stock is E. fruticosa. A less vigorous but reliable stock is E. obesa. E. mammillaris, which is often used, is reliable but seems short-lived. For the caudex-forming Madagascan euphorbias, such as E. capsaintemariensis, E. moratii, E. primulifolia or E. ambovombensis, Rauh (1987b) recommends as a stock E. milii var. hislopii.
Finally a further reminder in this section of the toxicity of the latex. If it comes into contact with the skin, it should be thoroughly washed off under running water.