Poinsettia

Family Euphorbiaceae. The genus Euphorbia comprises about 2,000 very different species. Indeed, it includes annual, biennial and perennial plants, evergreen or deciduous, as well as trees, shrubs and succulents that in nature grow in a wide variety of habitats.

Common to them is an inflorescence in the form of a false umbel and a milky sap that irritates the skin. Many euphorbia species are grown in the garden, and others as house plants. The best-known species - the poinsettia (Euphorbia pulcherrima) - differs from others by its characteristic inflorescence surrounded by red bracts that grow at the tips of the branches and surround inconspicuous yellow-cream flowers.

In spring the poinsettia is pruned, leaving stems 10 cm high from the ground. The soil should be almost dry; leave the plant in a bright place for a month. Then you can water the soil. By May, when the plant begins to grow, repot it into a not-too-large pot with good soil and place it in a bright location. From late May to September add fertilizer to the watering water and prune the branches, leaving 5 stems so that a strong bush forms. In spring and summer other varieties of shrubby euphorbias are planted in moist soil mixed with coarse sand, maintaining the temperature at 18-24°C and humidity, and placed in a bright location. Between June and September the soil should dry out between waterings; feed the plant every two weeks with liquid fertilizer. To give the bush a nice shape, trim the stems to about 15 cm above the base. Succulent euphorbias need dry air, sun and light; in spring repot them into soil mixed with sand, water regularly allowing the soil to dry between waterings and add liquid fertilizer to the watering water every two weeks. These plants also require different care in autumn and winter; the poinsettia needs shading with dark polyethylene for 8 weeks in a row for 14 hours a day, from evening until early morning. Water sparingly and keep in a bright place at room temperature; by Catholic Christmas, December 25, many bright bracts should have appeared (no wonder this plant is called the Christmas star). Other shrubby euphorbias are kept in moist soil at 13°C until flowering, then until spring, when cuttings can be taken, their watering is reduced. Succulent species are watered very sparingly, just enough to prevent the soil from drying out; they are kept in a sunny place at a minimum temperature of 13°C, protected from drafts.

Propagation: Shrubby euphorbias are propagated in spring by cuttings 7-10 cm long, cut from the stems. Dip the cut cutting in cold water to stop the milky sap from flowing. Then plant them in 7 cm diameter pots with a mixture of peat and coarse sand. Maintain a constant temperature of 18-21°C. Later repot the young plants into larger pots and care for them as for mature specimens. Succulent euphorbias: in spring cut off the grown apical tops of the stems, shorten them to 7-10 cm and immediately place them in water to stop the milky sap from flowing; then let them dry for a few days and plant them in 7 cm pots with a mixture of equal parts coarse sand and soil. The soil should be slightly moist; keep them in bright sun at 18°C, protecting them from drafts. After a month repot into good soil and care for them as mature plants. When handling cuttings, wear gloves and wash your hands well afterwards, since the sap of euphorbias is poisonous.

Problems and control measures: If a shrubby euphorbia stands in a draught, its leaves turn yellow and fall; with overwatering leaf spots appear and the inflorescences pale; in this case roots may rot and then the leaves and inflorescences will fall. The poinsettia sometimes suffers from gray rot; gray spots appear on the leaves and the lowest branches. Remove the affected parts and treat the plant with a suitable fungicide. If succulent euphorbias are kept in a damp room or are overwatered, their stems and roots rot; cut away the affected parts and move the plant to a drier location.