A nightmare for home owners everywhere, a very rare hybrid of Japanese knotweed has been found in Wales .

Japanese knotweed is an invasive species that spreads rapidly and is very hard to remove by hand or with chemicals.

If found on your property it can affect your house price and ability to get a mortgage.

The hybrid knotweed, known as Connolly’s knotweed was discovered during a study led by Sophie Hocking, a PhD student at Swansea University.

The plant, known as Connolly's knotweed is a hybrid of Japanese knotweed and Russian Vine.

Although this could mean further proliferation of knotweed, the Swansea scientists involved believe the discovery could help them develop new ways of managing the spread of this destructive and notoriously difficult to combat plant.

Sophie said: “We discovered evidence of Connolly’s knotweed during the study, which took place near Cardiff.  Connollys' knotweed is a hybrid of Japanese knotweed and the common garden plant, Russian Vine. While Connolly’s knotweed is rare in the UK, records of it are increasing across continental Europe.”

Is this something to worry about?

Put simply - probably not.

The Japanese knotweed in the UK is all female. It can not reproduce through seeds because there are no male plants. It can only spread if parts of its roots, which is actually an underground stem, is moved elsewhere (like by a river). These new plants are therefore clones of the old plant.

Though only a tiny bit of the root is needed to grow a new plant it is quite tricky for Japanese knotweed to spread quickly.

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However this is where the danger of hybrid plants comes in.

A hybrid could theoretically act as the male counterpart to Japanese knotweed and allow it to create seeds and therefore spread quickly.

Sophie added: "Connolly’s knotweed is a bit of a paradox because although it is rare in the wild, it’s the most frequently produced seed found on Japanese knotweed plants in the UK.

"We didn’t expect to find Japanese knotweed in the seed bank, because plants in the UK come from a single female clone and cannot reproduce successfully without male plants, unless hybridisation with another member of the knotweed family takes place. We actually didn’t expect to find any type of viable invasive knotweed seeds, because it’s extremely unlikely for any to survive wet UK winters.

"The fact we did find evidence of Connolly’s knotweed means that hybridisation took place – this could be an important aspect of the Japanese knotweed invasion that we are overlooking.

"Japanese knotweed is capable of producing copious amounts of seed when hybridisation occurs. If future climatic conditions become favourable for these seeds to germinate successfully, our Japanese knotweed problem might get worse. A seed bank full of hybrid knotweed could mean a second wave of invasion following treatment of the initial problem.

"Finding Connolly’s knotweed in the soil seedbank means that invasive knotweeds may now find an additional means of dispersal."

The team hope the findings will enable them to find more effective methods of fighting the species.