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Euphorbia Milii Seeds and Seedlings Production

Euphorbia milii "flowers" are actually specialized floral structures called cyathia (singular: cyathium). The large, colorful bracts are called cyathophylls, with the actual flower in the centre. Five nectar glands surround the flower- though usually inconspicuous, they may be colored in contrast to the bracts. The botanical details can be found in several references on the net.


Strongly contrasting color of the nectar glands enhances the subtle beauty of this Poysean hybrid.

In some cultivars most if not all the cyathia have abortive flowers and so are more or less sterile.


One of the most floriferous clones I know of, an old Tropica hybrid, often gives cyathia with small, abortive flowers. Surprisingly, the bracts survive for weeks without the flowers.

The flowers usually produce copious amounts of nectar and attract bees as well as ants. Bees visit young (female) flowers for this nectar but also frequent older (male) flowers to collect pollen and are the natural agents for pollination.



Many cultivars seem to actively discourage ants by secreting a sticky substance along their flower stalks onto which the ants stick and die. Keeping bees away from flowers to be pollinated can be done by tying a cloth mesh over the flower bunch or placing the whole pot in a mesh covered frame.

The central stigma matures first and may be seen glistening and receptive soon after the bracts open and before they are fully expanded. The male florets mature after several days - initially the anthers are not seen at all and they start growing out only later. In time the anthers burst, to reveal the yellow pollen.




A large flowered Poysean hybrid illustrates sequential female & male maturity in Euphorbia flowers. The plant in the top picture shows a young, still expanding flower cluster on its left - a close up of this on above left shows the green female stigma, moist and receptive. The older, fully expanded flower cluster at right on the plant in the top picture has flowers showing anthers, here shown in a close up at above right.



Close up of a smaller, red hybrid flower to show floral structures that are not so apparent. On left, the tiny red stigma is almost invisible. On right the anthers are more easily seen, some of them have burst to reveal the pollen grains.

Both cross and self pollination are possible. The procedure is fairly simple- pollen can be picked up on a brush or the whole anther can be picked up with pointed forceps and the pollen applied to the stigma.


Anthers can be picked up whole with a pair of forceps and used to dust the stigma with pollen. In this staged photo the anthers are closed- to achieve success, they must be split open, exposing the pollen grains. Note that the flower is young, just beginning to open and color up.

I pollinate flowers just as they begin to open- the anthers have still not emerged at this point so self-pollination is automatically avoided. Ideally the anthers should be removed as they emerge to eliminate any chance of self-pollination but in practice this is too tedious and is avoided. Any self-pollinated seeds are acceptable in our selection program. A lot of open pollinated seeds are also collected.

Each flower can give a maximum of three seeds and usually gives only two, often just one.




Various stages of seed pod development- top left they are just becoming visible as green dots deep in the flower. On top right they are now well set and growing. On left the seed pod is half mature.

One of the problems with seed collection is the explosive nature of the seed capsules. One has to either go over the plants several times a day (and even then some seeds will surely fly off) or else coat the immature seed capsules with a white glue like Elmer's or the clear synthetic glue used for paper. This will usually hold the whole thing together even if the capsule has exploded.



Two seed pods - the one to the front and right is ready to pick, the other still immature. This seed pod is ready to burst any minute, may do so as soon as touched.



Despite every effort, seeds will fly off. Here a seed has germinated in the gravel below benches and the seedling is growing quite well, showing just how tough and hardy these plants are. Seedlings will often come up in containers with other plants. A yellow flowered seedling co-habits a pot with a grafted Sri Amporn plant.

Seeds are quite fragile and easily crushed so must be kept in small boxes rather than envelopes. We use plastic containers equipped with a mesh lid- this allows seed pods to dry out and burst naturally.



Seed pods are picked and dropped into special mesh-top containers. After a day they burst and can be cleaned, to get relatively pure, ready to sow seeds.

Viability of Euphorbia milii seeds does not seem to be too long and they are best planted very soon in an open mix and covered slightly. Kept warm and moist they will germinate in a week or two. We plant seeds in community pots to be transplanted after they get a few true leaves. Plug trays also work well.



Seeds may be sown in community pots or individually in plug trays.

Typically, seedlings are initially transplanted into 6cm (about 2 inch) square pots. Our trays hold 40 of these pots so it's a very convenient and space saving system to start the seedlings. Many seedlings will start blooming in these small pots.



Vigorous seedlings in 6 cm square pots. These can be spaced out by adding empty pots between filled ones.


Transplanted into 10 cm square pots, the seedlings will all flower soon and the selection process can start.

We segregate the plants as per growth habit and then transplant them into 10 cm pots. These pots are big enough to flower even the robust hybrids. Once established in these pots we start the process of selection and elimination.




Top left & right: many seedlings will flower in small 6 cm pots, especially in winter. Almost all will flower in 10 cm pots- a round pot on left but usually we use square pots as they hold more media and save space, water and fertilizer.

Generally, the worst plants are discarded and the best are picked out and numbered for further study. The ones which look decent are sold as seedling selections locally. We are still left with a large number of plants which are too good to sell off yet not good enough to number. These are kept till they can be shifted to one category above or below. Overall, we find that the larger Thai type selections need time to show their worth while the smaller hybrids will often look good when very young but not live up to their promise after propagation and further growth.



Community pots of seedlings at a large Thai Poysean nursery. Thumb pots hold small seedlings at a Taiwanese breeders growing area on his terrace.

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