Euphorbia unispina N.E.Br.
Euphorbia unispina is a spiny succulent shrub with a stout, sparsely-branched stem that grows up to 13.1 feet (4 m) tall. The branches are up to 1 inch (2.5 cm) in diameter and usually have a few leaves at their tips. They are silvery-grey, covered with shallow tubercles and horny spine shields with a single spine. The spine shields are up to 0.4 inches (1 cm) in diameter. Flowers are yellow-green, 5-lobed, up to 0.2 inches (0.5 cm) in diameter, and appear and appear at the end of the dry season before new leaves are formed. There is only one female flower on each cyathium, surrounded by many male flowers.
USDA hardiness zones 9b to 11b: from 25 °F (−3.9 °C) to 50 °F (+10 °C).
How to Grow and Care
Euphorbias are very easy to care for. These plants require a little pampering to become established, but once they are, they are self-sufficient. In fact, more die from too much care and watering than from neglect. Euphorbias need well-draining soil and lots of sunlight. They are not particular about soil pH, but they cannot tolerate wet soil. Unlike most succulents, Euphorbia does not handle long periods of drought well. It may need weekly watering during the summer. Water whenever the soil is dry several inches below the surface. Water deeply, but don't let them sit in wet soil, which can cause root rot. Add some organic matter or fertilizer to the planting hole. If you are growing them in containers or your soil is poor, feed with a half-strength fertilizer monthly.
These succulents can be grown from seed, but they can be difficult to germinate (or even find). They are usually propagated by cuttings. This can be tricky because of the exuding sap. Rooting hormone is recommended with Euphorbias. They tend to grow problem-free, but there are a few pests and diseases to be alert for.
Learn more at How to Grow and Care for Euphorbia.
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