I have a small collection of plants which i grow indoors as I live in the UK and most of the plants are tropical/require warm climates. One of the plants I grow is a small catnip ("catmint") plant. Everyday I water and check on my plants for signs of pests and disease etc. This morning I noticed a tall hairy dull green stem growing in the catnip plant's pot. Either I had simply not noticed it before, or it has magically grown up to about 10cm overnight. Either way I would like to know if anyone can recognise this mystery guest of mine, and if they could let me know if it should be eradicated or if it is safe enough to have around [Pictures below]



On the left is a (sort of) close up of the plant in question. On the right is the plant in relation to the catnip in the pot.

Sorry for the bad quality, my camera refuses to focus on the right area :/