When people move around they often take plants with them to remind them of their origins. This kind of sentimental attachment to plants has produced some disastrous consequences in various parts of the world. South Western Australia is infested with sweet briar Rosa rubiginosa, taken there by early settlers as a fragrant reminder of the hedgerows of the 'old country' that they left behind. Similarly, settlers took purple loosestrife Lythrum salicaria to North America, where it has since run riot through wetlands, doing enormous ecological damage. It's commonly the case that European plants that are perfectly benign in their native habitat become botanical hooligans when they're shipped overseas.
This plant, traveller's joy or old man's beard Clematis vitalba is another example of a British botanical export that has run amok in its new surroundings. Traveller's joy was taken to New Zealand in the early years of the 20th. century and is now one of that country's worst weeds, climbing to the tops of trees and smothering native vegetation.
It's not a native species up here in North East England but it is in Sussex, where I grew up, and there it decorates hedgerows with its fluffy seed heads, so when we moved up here thirty five years ago I asked my family to send up some seeds, as a reminder of home. The two plants in our hedge produce plenty of these seed heads that look beautiful amongst the dying leaves, especially when they are back-lit by the low winter sun, and so far there are no signs of the plant spreading in its new surroundings. It really only thrives in limey soils, like those of the chalk downs of Sussex, and our soil here isn't alkaline enough, so I don't think I'll be responsible for a local invasion by this plant any time soon.
I brought this plant up here with me from Sussex too, although it's actually native to North Africa. It's winter heliotrope Petasites fragrans and, true to its name, it blooms from November to February. There are separate male and female plants but only males are known in Britain so there's no chance of it spreading via seeds. It is invasive though. I introduced just one small plant into my garden but it has creeping underground rhizomes and now the clone covers about four square metres, so I'll need to bring it to heel soon. It's not the world's most attractive plant but I grow it for sentimental reasons, because it grew on the roadside leading to our house in Sussex and because it has one distinctive feature that reminds me of childhood. The flowers have a wonderful fragrance of marzipan (though some think it smells of vanilla) and it reminds me of the smell in the kitchen at home at this time of year, when my mother was icing the Christmas cake.