Does Anyone Know What This Plant Is Please?

Question

It grows well in a sunny spot – Devon. Has soft stems that have white liquid in when cut. We’d like to plant more of it.

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Answer 1

This would be Euphorbia characias.

There are many, many species. Most of them have similar, to exact same care. This article will go over the care of Euphorbias:

https://www.gardeningknowhow.com/ornamental/cacti-succulents/euphorbia/growing-euphorbia-plants.htm