Plant identification request

[mirrorshard]

Does anyone know offhand what this is? Some previous owner or tenant planted it neatly in between the lavender & rosemary, right where I want to put more herbs, and as far as I can tell it's neither use nor ornament. (Obviously I have not attempted to apply the binary edibility test.)

Comments

[friend-of-tofu.livejournal.com]

Also, don't worry too hard. I stupidly tore up some rainbow chard because I didn't recognise it. My mother was the one who identified it. Bang went that free food from the previous residents!

[mirrorshard.livejournal.com]

I'm 90% sure it's not food, and it hasn't done anything interesting like flower since September, but I don't want to get rid of it without a) being certain and b) making sure it's safely compostable or burnable.