Jättipoimulehti – Alchemilla mollis

Tämä laji on vieraslaji, jota ei ole säädetty haitalliseksi eli se ei kuulu kansalliseen eikä EU:n haitallisten vieraslajien luetteloon, ja esimerkiksi lajin myynti ja kasvattaminen ovat edelleen sallittuja. Kaikkia vieraslajeja koskee kuitenkin vieraslajilain mukainen ympäristöön päästämisen kielto ja siksi niihin on syytä suhtautua varauksella.

Garden lady’s mantle is a strong competitor and spreads efficiently because it has a long life span, sturdy roots, is tall and frondose, and propagates vigorously even from seeds. This vitality can cause problems in yards and gardens, but may also lead to the plant becoming widespread in the environment. Each flower of garden lady’s mantle produces one seed at most, but due to the vast number of flowers in each individual, the total number of seeds may become very high. The seeds can travel far with the help of animals and the wind in particular; the large calyx remaining on the top of the flower during fruition can serve as a prehensile and flying device. The garden lady’s mantle also tends to bed down in places where its roots or root fragments have travelled alongside humans, soil or flood water.

Garden lady’s mantle has spread to Germany, in this way, from low-lying urban centres to the subalpine zone in the mountains and has thereby become more or less part of the natural vegetation. In the British Isles, Alchemilla mollis was found in the wild in only five inventory screens of 100 square kilometres by 1968; but in 2002 it was found in more than 800! The Netherlands has faced a similar massive invasion: 27 squares (5 km x 5 km) by 1990, 290 by 2005 and 668 by 2014. Even in these countries, the spread of the species has included the invasion of vegetation in its natural state, such as riversides. In the Faroe Islands, garden lady’s mantle has even settled on vertical mountainsides. In Norway, it is classified as a high risk invasive alien species, with a vigorous ability to penetrate natural vegetation, thereby producing adverse ecological consequences.

Native to very high mountain regions, garden lady’s mantle may, if released, cause genuine problems in the treeless or sparsely wooded environments of Fennoscandia, possibly all the way up to the lower treeless tops of fells. The explosive spread of the species in Iceland and the Faroe Islands, in particular, justifies this concern and thus the inclusion of the species in the list of potentially harmful alien species in Finland.

In Finland, a possible invasion of garden lady’s mantle can still be avoided by refraining from the cultivation of the species, particularly in the north, by flowing waters and in public mass plantings, and by preventing it from escaping. The species should not be included among species suitable for landscaping in the region of high fells in the Käsivarsi area of Finnish Lapland, as it recently was. Escaping can be prevented by the appropriate treatment of garden waste including roots, by cutting withering inflorescences before the seeds are ripe - this may promote repeated flowering and thus extend the ornamental character of the plant (all subsequent flowers must, of course, be removed before the seeds develop). All individuals found in the wild must be eradicated by carefully removing all parts of the plant and then composting or burning them properly.

Consider the issue from your and your environment’s viewpoint if you are planning to acquire garden lady’s mantle for your garden. If you acquire it, follow the instructions given above to prevent the spread of the species.

Learn to recognise garden lady’ mantle and report all observed escapees via the Invasive Alien Species portal, preferably accompanied by a photograph enabling verification (a sufficiently sharp close up of the flowers taken from above is necessary).