Indoor and greenhouse euphorbias
Common name: Crown of thorns, thorns of Christ
With a resemblance to cacti, these euphorbias are from tropical and arid regions and so grown as houseplants. From small ball-like plants to large branched shrubs, they are generally easy to grow in sunny rooms, but are ideal for sunbaked conservatories and can be placed outside in the height of the summer in the UK. Poinsettias are also indoor euphorbias, but we cover these on their own page as they are so popular and widely grown.
These euphorbia have very diverse appearances, but all have have swollen, sometimes segmented and often leafless stems. Some are ball shaped, others have long lanky lax stems, others erect, branced and upright. Many produce every few years in shades of red, white, pink or yellow flowers in spring or summer.
Position in a well-lit spot in the house, particularly over winter. The compost is kept just moist in summer, and allowed to dry in the winter. Some plants are happy taking a summer holiday in the garden in summer, but do check the minimum temperature needed by individual species.
They dislike cold, wet conditions, particularly over winter, so be sparing with the watering. Hot and humid conditions can also lead to disease (such as rotting of the stem and roots), so keep plants in a sunny spot and ventilated in summer where possible.
Did you know?
Euporbia are not true cactus as they do not have areloe - the cusions or small depressions on the stem from the which the spines emerge. As a result, they are classed instead as succulents. They still share many of the physiological adaptations to survive in hot, dry hostile environments, and this is why they generally look pretty similar to cactus.
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