Are you trying to get rid of me,Galina? Lol ....just joking.
This is what your link says about the stevia seeds:
Hairy green foliage and small white flowers. Part of the James Wong Homegrown Revolution Range. Ornamental herb.
Grows well in pots on your patio. PLEASE NOTE: Plant not approved for human consumption.
That's old news - there was a time when stevia was not approved for human consumption, not because it causes any problems to health, but because it hadn't undergone rigorous testing like drugs have to. However now that you can buy powdered stevia sweetener in Asda (and presumably other places too), they must have finally got it approved.
James Wong - do get with the times on your seed packets!
Gazza, I got one plant, lives in the conservatory, sprouts during summer, dies down in winter. Had it for 3 years now. Has never flowered. Every spring I top up the compost and give a little fertiliser when I see the new growth. The leaves are very sweet. I stick them in with stewed rhubarb etc and with bottled tomatoes that have to have a spoonful of vinegar added, to counteract the acidity. Lots of uses, but you'd need a dozen plants to replace all sweetener.