based on the size of the plants show at the link .. neither is going to last long.. in that pot ... so why not try to separate them now ... it isnt going to be any easier.. when they are bigger ..

maybe the little one.. is lacking the full sun.. a SUNflower needs ... and who knows what is going on under the media ...

ken

https://www.google.com/search?q=black+oil+seed+sunflower&source=lnms&tbm=isch&sa=X&ei=BYxkVfyKBoaAygSUoIGgDw&ved=0CAgQ_AUoAg&biw=941&bih=745&dpr=0.9#tbm=isch&q=black+oil+seed+sunflower+plant

I actually used the same pot for two sunflowers last August and they grew pretty tall, no growth fertiliser. Here are the photos http://bit.ly/1qAn1Vi .

The reason I am thinking of clipping out the deformed second sunflower is because prior to this I used the seeds from my first two sunflowers which I mentioned above to grow a sunflower in the same pot but it came off as rather short and did not produce any healthy seeds and succumbed to white sugar bugs in the end, I have photos here http://bit.ly/1Gk0Xe1

new media.. for the new season ???

no reason not to just snip out the smaller.. its not really time to be transplanting something the size of the larger ..

good luck

ken

Alright I'll snip out the deformed one tomorrow. I'll do it at the base of the soil. I'm assuming the roots will just die and start composting down allowing the bigger plant to thrive.