There have always been reports of more exotic orchid species being found in Britain, but in recent years this has become more frequent. Most orchid followers will be aware of the Serapsias found a few years ago in a field in Tiptree in Essex, and then there was the Fly x Woodcock hybrids in Dorset. I have been to see the Giant Orchids growing in Oxfordshire, but there are two more colonies of these. Now there seems to be a rash of various species of tongue orchids being found in Britain. I am not going to waffle on about whether these are ripe for conservation efforts, nor whether they are deliberate introductions, accidental introductions or from wind blown seed.

What I want to know is do I count these as British species and add them to my list as seen or to be seen? I have added the Irish Lady’s-tresses growing in a field in Wales and will be adding that Giant Orchid (even though someone has confessed to introducing the Kent colony). What counts is whether they are here to stay, at least in the medium term. How long do they have to survive in order to be British by my (or other’s) reckonings? The Essex tongues seem to be up and down and the Giant orchid did not look as happy as those I have seen around the Med.

Discounting deliberate introductions there does seem to be a trend for some species to be extending their range northwards across continental Europe. This could be linked to climate change or it could just be part of a natural process. I suppose once they reach the North Sea and English Channel windblown seed could arrive here anytime and increase to the number of British species. Then there are those folk who have taken plants from continental Europe and planted them with some success in their gardens. I am thinking of a cottage near Ilminster in Dorset with Serapsias and Ophrys species growing on the road verge in front of the house. These have the potential to colonise the area. Of course success is dependent on a number of factors. Not just climate and habitat, but also presence of pollinators. However here is a list of species, according to Kuhn, that are approaching our shores.

Anacamtis laxiflora. Has reached France’s Channel coast. However the introduction at RHS Wisley was not a success.
Anacamptis palustris. Also reached the Channel
Anacamptis coreophora. Grows in Brittany
Anacamptis fragrans. Also in Brittany
Ophrys scolopax. Up to the northern end of Biscay
Ophrys passionis. Brittany again
Ophrys areneola. Normandy
Ophrys fusca. Brittany,
Ophrys lutea. Brittany
Ophrys speculum. Biscay coast
Dactylorhiza sphagnicola. Belgium and Holland.
Dactylorhiza sesqyuipedalis. the area around Le Mans
Dactylorhiza majalis. Channel coast. These three species should cause some hybrid fun if they ever reach Britain.
Gymnadenia odoratissima. Normandy
Platanthera latissima. North coast of France
Platanthera muelleri. Southern Belgium and Holland
Spiranthes aestivalis. Extinct here, shows no sign of willingness to be reintroduced, but grows in northern France
Limnodorum abortivum. Northern France.
Serapsias cordigera. Biscay coast, but reported from Yorkshire
Serapsias vomeracea. Biscay again, but reported from Kent
Serapsias bergonii. Reported here, but nowhere close on European mainland
Serapsias lingua. Brittany and and several English finds
Serapsia parviflora. Brittany and reports from Cornwall. Suffolk and Midlands

Note how the Mediterranean genuses (Ophrys and Serapsias) are spreading up the western side of France while all the others (Anacamptis abd Platanthera) are spreading north of the Alps. All of these could spread to the UK and become bona fide residents. I have seen most of those tongue orchids abroad? Can I count this as seeing them for my British list. Quite a dilemma.
 

I said earlier that this can be put down to climate change. However I would propose that we are still seeing the recovery of higher flora to northern Europe following the retreat of the last ice age. This didn`t end when Britain became detached from continental Europe. It is a continuing process. The last ice age across Europe ended 12,000 years ago. When the ice retreated the orchids advanced - slowly of course. The British mainland split from Europe 8,000 years ago, creating a barrier to further northward encroachment. However, this barrier is not insurmountable due to wind-blown seed. It just delays orchid spread. What may halt the expansion temporarily are the major climate fluctuations. In the last 2 millennia, for instance, there was a cold and wet prolonged period during the Dark Ages, and then the mini ice age in the 1600s. Between these was a medieval warm period. We could well still be in a warming period after the mini ice age. Thus the post-glacial northward spread has not ended. It is still happening, and is probably now helped by global warming. Look forward to some exotic species in the upcoming decades.

Having said that, there must be a downside. Early colonisers after the ice age are probably those most prolific north of the Border in Scotland. Creeping Lady`s-tresses, Coral Root and Small White Orchid are examples. They are largely absent from England suggesting they prefer cooler, damper conditions. It is therefore likely that they will be pushed further and further north, until they can go no further. However, this should be seen as natural progression. If their were not any past extinctions we could be sharing the great outdoors with sabre-toothed tigers! There is an exception to the north British orchids - the Northern Marsh Orchid, which is showing signs of gradual creep southwards. This could be because the polyplod even that gave rise to this species happened up north, and it has not yet found its southern limitations. It may have spread across the Channel and North Sea to Norway, Jutland and Holland.