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Euphorbia Milii Propagation

Euphorbia milii are, as a group, easy to propagate. Specialist Thai growers have worked out rapid propagation techniques and can produce large numbers of new plants from a single new selection very rapidly.

SEED PROPAGATION:
Seed production and the techniques for raising seedlings are described in detail in the SEEDS & SEEDLINGS Section.

Since all the hybrids in cultivation, especially ours, are complex crosses, they never come true from seed; indeed, give extremely variable seedlings. Thus growing Euphorbia milii from seed is not really a viable means of propagation but more a means for producing new hybrids for further selection.

GRAFTING:
For the Thai type of hybrids, this is a common propagation technique. Grafting works very well using a special rootstock called Daeng Udom but any strong, healthy grower that is easy to root can be used. Daeng Udom is a vigorous grower with strong, single thorns that help anchor the thread that hold the two pieces together.

The mother plants for rootstock production are usually grown in ground beds and 10 cm cuttings are taken and rooted under a polyethylene sheet tent. The cuttings are graded both, before sticking and after rooting to get a relatively uniform lot of rootstock material. This grading of all their material is one of the factors differentiating the specialist growers from the ordinary. Only well rooted, uniform material is used for grafting.





: Series of pictures showing the process of grafting Poysean in Thailand. Note the way the thorns on both, the rootstock as well as the scion, provide anchorage for the thread. The Thai grower demonstrating the technique is a pioneer in bulk propagation of Poysean and has a stall at Chatuchak.

The scion is tied to the rootstock with plastic string and the whole pot covered with a clear plastic bag for 10-15 days, by when the union is formed. The video clip shows how fast the whole process is in the hands of an expert.


Small graft in a thumb pot ready for shipment to Japan. Even such small grafted plants will flower profusely.

Despite the speed at which grafting can be done, there is limited scope for this method of production when volumes are very large. In the initial period when Thai hybrids were sold for high prices it was possible to accept the cost; now with the low prices, a lot of growers have turned to cuttings as the propagation method. Such plants may not have as long a life as grafted material but they are fine for low cost pot plant production.


It is possible to graft E. milii onto other species, as seen in this multi-grafted specimen in Indonesia. The rootstock is a common Euphorbia species used as a hedge plant.

CUTTINGS:
Current Euphorbia milii hybrids in Europe are all selected for good basal branching and ease of propagation by cuttings. In the modern context, it is the only viable means of propagation and even the Thai hybrids are being propagated by cuttings now.


Commercial starter plants of Euphorbia milii hybrids in Europe are sold as trays of rooted cuttings. Planted into 12 cm to 14 cm pots, they are ready to sell in 4-6 months.

Cutting grown material is cheaper to produce and easier to ship. Some Thai material now being exported to Europe is in the form of unrooted cuttings though cuttings rooted in coconut coir in tiny pots are still used, especially for the Japanese market.



Poysean rooted in Thailand for export to Europe and Japan. Pure coir is used as the rooting media.

The procedure for taking cuttings is fairly straight forward: a sharp knife is used to cut the branches. Cutting size depends on the cultivar. Thai material is generally around 10 cm in length while the European hybrids are nearer 5 cm and rooted in plug trays. A rooting hormone powder may be applied to the base, taking care to keep the auxin concentration low.

Pure coconut coir (check for EC- should be less than 1.0 mS) works well. A coarse peat or similar should be equally good. Some drainage material such as ground Styrofoam (thermocole) may be used to open it up a little. We use our 6cm sq pots which fit 40 to our holding trays for rooting cuttings. The smaller varieties can be rooted in plug trays. Most cuttings root fairly easily and should show new growth in about 30 days when they can be weaned from the rooting chamber and gradually hardened. Take care to remove any dropped leaves and rotting cuttings daily to prevent spread of infection.

OTHER MEANS OF PROPAGATION:
The above are the main means of commercial propagation. There are other methods, primarily of academic interest.

PUPS:
In some cultivars, flower stalks do not fall off but rather become green and hang on the plant. Given time, such "flowers" will often put out small pups which can be cut off and rooted. This demonstrates that the flowers are actually vegetative structures and proves the presence of axillary buds there.


A pup just beginning to form- after a while it will have a reasonably hard stem and can be cut off and rooted.

If kept on the plant these can grow quite robust and the flower stalk will thicken and become branch like. It is possible to cut off the flower stalks of some of the most vigorous cultivars and root them directly like cuttings. This is a hit or miss system and gives very non uniform plants.

AIR LAYERING:
This method is of interest with some old Thai cultivars which refuse to give any branches and keep getting taller with age. You could take a cutting from the top and root it but there is the risk of loosing it and be stuck with a rooted stump that will not branch. In such cases, to reduce the risk of loosing the plant, it is possible to make a little cut in the stem, tie rooting material like coconut coir around it and cut the top once rooted.

LEAVES:
Once in a while a leaf midrib breaks and the leaf will slowly develop a small callus at the break. Occasionally this will also throw roots. Just once I have seen a pup form at the callus after many months- interesting curiosity but not a practical means of propagation.



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