Exploding caper spurge
Q This plant is taking over my rockery – can I dump it in my compost bin? M BRAMLEY, NOTTINGHAM
A Your plant is Euphorbia lathyris, also known as caper spurge. It’s biennial, so after flowering and producing seeds it will die down. When pulling it out, wear gloves because the sap is an irritant, but it won’t do much harm in the compost heap. However, because the seed is ejected explosively from the three-lobed purple capsules, helping the plant spread quickly around the garden, keep a lookout for new seedlings. Hoe them off or pull them out as soon as you see them. It’s also worth spreading a thick mulch of bark chippings or compost to prevent any new seeds from germinating.