|Euphorbia characias wulfenii|
Note that all plants in this family have white, milky sap that will irritate and even burn your skin. Be sure to wear rubber gloves and long-sleeved shirts when handling them. I've had some nasty burns working with these plants, even when I thought I was being careful. This sap is poisonous if ingested - the level of toxicity varies depending on the cultivar.
There is a variety of Euphorbia called a mole plant or gopher plant ( E. lathyris) because it is believed that the poisonous sap will kill burrowing rodents who attempt to feed on its roots. I've never known this to work. Moles eat worms and grubs, not plant material. For more on what doesn't work, here's an article from MoleCatchers. To get rid of moles, you have to set traps.