Garden lupin – Lupinus polyphyllus

Garden lupin is native to western North America, where the natural distribution range extends from Alaska to Wyoming and northern California. It was introduced to Europe as an ornamental plant and for use as feed in 1826.

Garden lupin mainly reproduces from seeds, but vegetative reproduction is also possible. Seeds are ejected a few metres away when the pods open, and they are carried further through roadside mowing, as well as with soil and garden waste.

In Finland, the first escapes of garden lupin were reported as early as the late 19th century. Currently, it grows throughout the country, except for the northernmost parts of Lapland.

In Southern and Central Finland, it has increased exponentially since it has eagerly been spread to gardens and yards of summer houses, from where it has escaped further to road verges. In the Oulu region, the occurrence of garden lupins is concentrated on the banks of the River Oulu. From gardens, it has also escaped to wastelands, roadsides, railway embankments, meadows and fields, and even to forested ridges.