The Euphorbias, are plants belonging to the family of the Euphorbiaceae. Most of them are herbs but there are also trees and shrubs.
The best known is Euphorbia ingens . This notion of species actually includes several forms: E. candelabrum is found in East Africa: Kenya, Sudan, Somalia, Ethiopia … The leaves are quite small and fall quickly. The dark green stems waved a little as they age. They carry small black spines arranged in pairs. On very old plants, small yellow flowers appear in summer and turn into fruits with 3 lobes that burst at maturity, throwing the seeds to several meters!
Culture of Euphorbias
Euphorbia are not houseplants. Their culture in a house or an apartment does not allow to offer them ideal conditions. It is however possible to cultivate them by respecting some rules. They will not have, of course, the size and the vigor of those cultivated in greenhouse or outside (under favorable latitudes), but will nevertheless be able to accompany you during many years.
This species is not very demanding at the level of the substrate, a classic 3/3 mixture (one third of coarse sand, one third of potting soil and one third of light earth) suits him very well. Failing that, or for safety, we can increase the proportions of sand, add gravel, but 1/3 of soil is a maximum. A substrate that is too humic would be too rich, would take longer to dry than a conventional substrate and would greatly increase the risk of rot. Depending on this, if one is not sure of the correctness of its waterings, it is more prudent to lower the proportion of compost to 1/4, even 1/5 and to compensate with a very coarse sand or small gravel. In summary, the substrate must be very draining and dry very quickly. It is an essential condition.
Contrary to popular belief, succulents, like all plants, need water, especially if we want to see them thrive. The difficulty is, whether arid or semi-arid, these euphorbia do not support that their substrate remains wet too long. This inevitably causes the appearance of rots in the roots, then spreading to the body of the plant. It is therefore necessary to test the quantity of water necessary to ensure complete drying of the substrate in 2 or 3 days.
The drying will depend, of course, on the size of the pot, the quality of the substrate, the size of the plant (and therefore its water needs) and the temperature, the parameters are too numerous to indicate a precise quantity but the test to define it yourself is simple. Just choose a measurement, set one, and see the drying time, then increase or decrease it so you do not exceed the drying time.
All the substrate must be wet. The majority of the roots are in the lower half of the pot, just wetting the surface could give the impression of having watered but would not benefit much to the plant. Hence the importance of a very draining substrate, to allow water to penetrate the heart of the root ball while allowing a very fast drying. When watering, arrange a saucer under the pot to collect excess water. This must imperatively be emptied when the substrate has made all the water unretained.
Although an amateur who knows his plant well can water it a little more often depending on the conditions, it is better for a beginner in this crop, to water only every 10/15 days depending on the temperature and therefore the drying speed of the substrate. In all cases, the substrate must be completely dry for several days before re-watering. And this, not only on the surface, but also in depth. While it is not mandatory to water in winter a plant kept in the greenhouse or outside to respect its rest period, it is better to moisten a plant once a month during the winter. inside. Indeed with home heating, the roots could dry excessively and compromise a good recovery in the spring.
This is not because in our eyes a room seems very bright, that it is really and sufficiently for a euphorbia. These plants live normally in full light, in countries much closer to the equator than Europe, one must not forget it. Euphorbia need a lot of light, a location in front of a large window oriented SE or SO will be satisfactory, provided you are close enough. With exposure to the south and at the height of summer, it is advisable to remove the plant from the windows because the epidermis could burn. A curtain, provided it is light enough not to lose too much light, will allow in case of too much sunlight to avoid burns,
We may tend to forget it, but before being an object of decoration, an Euphorbia is a plant. It is impossible to want to decorate the bottom of a poorly lit room at the same time, or to close shutters during the day and see the plant prosper.
Those who have a balcony or terrace, can go out on sunny days, provided you put it in a very bright place but sheltered from the direct sun. Exposure to the direct sun is obviously possible, but it requires gradual and careful acclimatization because euphorbia are subject, just like us, to sunburn. The difference is that the euphorbias keep for life the traces of these burns.
For this reason, do not suddenly turn a plant exposed to the sun in summer, but do it very gradually. Parts in the shade, not being used to direct sunlight, could be injured.
Frequent problems exhibit by Euphorbias and their solutions
Branches whose ends are thinning, “spinning”. Plant turning pale.
Lack of light. Place it in front of a window.
Brown spots and clear or purplish along the stems, on the side of the exposure: sunburn.
Indoors: move the plant away from the window or put a very light curtain. Outside: shelter the plant from the direct sun. The exposure was too brutal. The plant will not heal because the burned tissue does not regenerate, but it will not affect its growth.
Extremities of brown, shriveled and hard branches: dehydration.
The plant was not watered enough. Lack of care that often goes with bad exposure. The plant fades, becomes exhausted and dies; the ends are affected first. Stakeholders should be cut to the level where perfectly healthy tissues appear.
Dark brown to black spots, soft tissue: rot
Excessive watering or infected wound. Can occur at the foot or anywhere on the trunk or branches. If in doubt, incise at the spot, if the latex (white) flows, doubt is possible. If it is a brown or black liquid, it is definitely a rottenness. Stakeholders should be cut to the level where perfectly healthy tissues appear.
Round black spots on the stems: cryptogamic disease
Lack of ventilation, situation too dark or too wet. Fungi grow on the surface of the stems. Place the plant under better conditions, eventually treat with a multipurpose spray fungicide. Black spots will dry up, but will not go away.
Types of Euphorbias
The latex of euphorbias is toxic. For any intervention on these plants it is imperative to wear gloves and protect the eyes. Any contact with a mucous membrane is extremely irritating. In case of latex contact with bare hands, wash your hands very thoroughly by rubbing vigorously with, for example, a scouring sponge. Or better, clean your hands and nails with alcohol, which dissolves easily the latex coagulated on the skin. The latex could remain in the fingerprints and cause irritation (lived experience …).
As the latex is toxic, it is preferable, if one does not have an instrument reserved for it, to use a disposable tool. The ideal in this case seems to be a cutter which can be thrown away.
If we cut one or more branches:
Protect the floor from latex dripping.
If you lay the plant, put balls of newspaper between the branches so that they do not injure each other. The scars would remain visible.
Cut all infected parts with a disinfected tool before the first one, and after each cut where necrotic tissue has been cut so as not to spread the germs. No brown spot, even very clear, should remain. The cut must be perfectly white. To stop the flow of latex, pour water or dab with a damp paper towel. The latex coagulates instantly.
The cut must be clean and horizontal. The best is then to cut each bevel edge if you want it to be the most discreet possible then. If you have to work on the whole plant, think that at the cut level, on the branches, a tuft of new branches will grow (usually one to two per rib if it is in shape). In addition to a branched aspect rather welcome, this will change the balance of the plant. It is therefore good to predict this in order to cut at the most sensible place in anticipation of the subsequent growth of the plant. This will allow it to develop in a more balanced way (and therefore more aesthetic).
Wash the plant to eliminate any latex dripping.
Disinfect the cuts with cinnamon powder or betadine. It is not obligatory but preferable.
Sort in what is cut, the parts that can give rise to cuttings. A section of 15 cm is sufficient, even if it is a section cut at both ends.
If the plant is outside the shelter from the rain time the wound is well healed. The duration is variable according to the climate but at least a month as a precaution, more is even better. A protective callus must cover the wound after drying. In the absence of the host plant, harboring at least the cut allowing it to breathe (no closed plastic bag around the branch …). Outside bevel is indispensable to avoid water stagnating at the cut parts.
If you have to cut the foot, treat the whole plant as a cutting:
Allow the plant or cuttings to dry for one to two months depending on the diameter, preferably in a cool but dry place. A thick callus must cover the cuts. It is better to let dry too long than not enough, because a call too fine would not ensure the tightness of the foot of the cuttings and there is a risk of further rot. As long as the plant does not show signs of “wilting”: everything is fine!
An approximation can be made with one week of drying per centimeter of stem diameter off the coast, with a minimum of one month.
Put in pot, do not water for 15 days then slightly wet the substrate, only
on the surface, to stimulate the development of the roots. The cutting has no roots it is useless to overwater it would only risk making it rot. So wet once a week, just the thickness of soil corresponding to the burial depth of the cutting, for two months. Adding a little fungicide to the water may limit the development of fungi and thus limit the risk of rot at the place of the cut which remains a fragile part.