I think this is Skunk cabbage ! Its a non native species to the UK and is very invasive and kills all plants around it. Some volunteers have been cleaning this from the Allander - this one was seen at the Allander at Tesco in Milngavie. Not sure if it is found in the Allander going through Mugdock but hopefully the volunteers will have some success in getting rid of it. It looks very alien and triffid-like to me !