While visiting England and Finland my husband and I traveled by train. (Wonderful! Wish we had good trains in the U.S.) In both countries I noticed beautiful flowers blooming along the rail lines. As I feared, the flowers are invasive.
England's railroad flowers:
In England the railroad waste places are crowded with butterfly bush, Buddleja davidii (pronounced "BUD lee ah"). Originally from central China and Japan, buddleja has many cultivars and is planted around the world for its beauty. It's now invasive in most temperate regions outside its homeland including England, New Zealand and North America. Yes, it's invasive in Pennsylvania. Here are Three Reasons to Never Plant Butterfly Bush Again.
Finland's railroad flowers:
In Finland I was surprised to see so much lupine because it's a treat to see it growing wild in North America. Unfortunately Lupinus polyphyllus was imported for Finnish gardens and has escaped to waste places along the roads and railways. It's everywhere! When I remarked on its beauty our Finnish friends said, "It's awful! Very hard to get rid of." Here's some lupine by the railway, taken from inside the train to Helsinki.
Click here to read about five invasive species in Finland. The North American mink is one of them.
Pennsylvania's railroad flowers:
Though it's hard to find a passenger train in western Pennsylvania, we still use railroads for freight and, yes, we have railroad flowers. Ours are orange daylilies (Hemerocallis fulva), a garden cultivar from East Asia that grows wild along roadsides and rail lines. This gave it two nicknames: Ditch Lily and Railroad Lily.
Orange daylily seeds are sterile so the plant spreads by fibrous roots and rhizomes. These are so hard to get rid of that the plant is invasive in Pennsylvania.
Many invasive plants line the roads and railways of the world. Fortunately the railroad flowers are beautiful.
(most photos are from Wikimedia Commons; click on the images to see the originals.)