The Tromsø Palm – a vital immigrant to the North

“Heracleum (…)is frequently planted here as some kind of hedge along the paths in the gardens. When flowering, it reaches a height of up to 8 feet. The sight of these gardens will never, therefore, fail to astound any southerner on his first visit to these northern latitudes.”                                                                                                         – J.A.Friis, 1874.

 

Both King Oscar II and his chronicle writer Friis were amazed when they came to Tromsø during the King’s coronation tour in 1873. They found a lovely little town between mountains and fjords, rich in culture and civilization, despite its remote location. This was evident not least in all the well-kept gardens, seen both in the town centre and by the numerous summerhouses and cottages scattered across the Tromsø Island. In many of these gardens, King Oscar noticed a peculiar and impressive plant; The Tromsø Palm.

 

This plant is still here, and visitors to Tromsø can’t fail to notice it either summer or winter. It has thrived in Tromsø, so much so that is has become an icon for this city and derived its name from it. The large, lush leaves rise up above grass and herbs on meadows and open turf among houses, the wide umbels hover on long stalks from flowering time in July and all through the winter. The silhouette of dry umbels against the pink winter sky is a very popular photo motif of Tromsø.

 

The inhabitants of Tromsø both love and hate their voluminous and strong-growing land mate. In the spring, it bursts with life and grows so fast it is observable from one day to the next. In the summer, the white umbels stand out bright in the midnight sun. During autumn and winter, the dry stalks are useful as children's toys. Dried umbels are seen as ornaments in shops and private homes, “The Palm” is turned into designs for textiles and paintings, it appears in jewellery and souvenirs – it is so important in the minds of the Tromsø citizens that it even adorns the city’s festive costume. Always associated with Tromsø, it appears frequently in advertising and media.

 

At the same time, the Tromsø Palm is a problematic plant. Spreading like the most aggressive weed, it poisons the soil where it grows and outcompetes most other plants. It can produce more than 5,000 seeds per year, and the roots are so large and deep that they cannot be pulled up. Wherever the Tromsø Palm establishes itself, the local vegetation alters. It is a pest, harmful to natural flora and as so many Tromsø inhabitants know, it is nearly impossible to kill. Avoid breaking stems and leaves off the fresh plants – the juice inside will cause blisters and rashes on human skin, particularly if exposed to sunlight.

 

Yet this bulky, successful species does not occur naturally in Norway. 200 years ago not a single “palm” was in sight. So where did it come from – and how? These questions form part of recent research at Tromsø University Museum, and new information now sheds light on the history and origin of this plant.

 

Records show that guests from Great Britain brought seeds of the plant along to Hammerfest and Alta in Finnmark in 1836. It arrived to Tromsø about 15 years later, when Mrs. Nanna Sabine Mack took seeds from her home in Alta and sowed them at “Elvebakken” (River Hill) the summerhouse of the Mack family. A photo from the summerhouse taken some 50 years later shows that the Tromsø palms thrived there and put their mark on the garden, perhaps more so than the owners would have wished.

 

The large, lobed leaves and delicate, white flowers was just right for Victorian taste, and the Tromsø Palm quickly became popular across Northern Norway. Garden owners brought it along to new places, and some probably orders more seeds from plant dealers in Germany. In the second half of the 19^th Century, the Tromsø Palm entered gardens all along the coast, many places becoming an instant favourite because of its size, particularly in weather-exposed areas where trees and shrubs were hard to grow.

 

The Tromsø Palm has for a long time proven something of a mystery to scientists. It undoubtedly belongs to the genus of Hogweeds (Heracleum), but it has not been an easy task to pinpoint its exact place in the botanical taxonomy. Hence, it has had various names through the ages. In the 19^th Century it was known as Heracleum panaces, but through most of the 20^th Century it’s been referred to as Heracleum laciniatum, and even Heracleum tromsoensis has been suggested.

 

With the latest developments in Tromsø Palm science, researchers has now decided on Heracleum persicum – i.e. “the Persian hogweed”. So what has Persia got to do with it all? Well, it turns out that modern-day Iran is where we can find what must be the origin of the Tromsø Palm, and that is where those seeds that made their way to Alta in 1836 most likely were collected.

 

Along the south side of the Caspian Sea, up in the mountains, grows a Tromsø Palm plant known in Persian as golpar. It does not grow quite as large as the plants in Norway, neither does its juice cause blisters or rash, but analysis of the DNA from this plant reveals that it is indeed the same species as the Tromsø Palm.

 

In Iran, the golpar is a very useful plant, both for cooking and traditional medicine. The seeds are ground to a powder used as spice. Golpar is not an aggressive plant invading the land where it appears. Overall, it seems to be more balanced and in tune with the surroundings in its homeland.

 

The study of the Tromsø Palm DNA has also shown that the route it took to Norway went through Denmark and Finland as well as England, and that the genetic variation among the Tromsø palm plants in Norway is very small. The latter is usually a disadvantage for the survival of natural species, but the Tromsø Palm is a striking exception from this. It is an exotic immigrant which, assisted by humans, conquers a large part of the country, outcompetes local species and enchants the people to such a degree it makes an almost instant evolutional success.

 

The Tromsø Palm is now beginning to appear even on sites unpopulated by humans. This is a clear sign of its ability to establish itself as a wild species in nature, with no intention of keeping nicely inside old garden fences. Scientist agree that we need to control the Tromsø Palm, lest it causes severe harm to our nature. Future progress in Tromsø Palm research will probably consider how such control is best obtained.

 

The exhibition “The Tromsø Palm – pretty and perilous” is on display at Tromsø Museum until January 29^th, 2017. It will later be obtainable as a travelling exhibition.

Last changed: 03.10.2016 10.47