I may be wrong but I think this is the same (or very similar) as Salvia algeriensis. This is a wholly delightful annual species, which will flower within 3 months from sowing. It likes a sunny spot, with excellent drainage. Very large blue/purple flowers.

Certainly not a menace, it is an absolute gem. Short flowering period in early summer, which can be prolonged by dead-heading. Collect the seeds for next year.

An easy Salvia to grow... weird that it is not more well-known.... stunning when in full bloom. Try 5 plants in a a large container. When the flowers are over in early August, replace with...well, the possibilities are endless.

Very best wishes from the UK...... -10 again last night!

Robin.