Common Viper's Bugloss (Echium vulgare)
When driving to town yesterday, I made stops along the road to check out what was blooming. Here is a selection from what I found. Can you pick out the native plants from the exotic imports? Look them over, and then scroll to the bottom of the post for the answer.
Bladder Campion (Silene vulgaris)
Red Clover (Trifolium pratense)
Bird's-foot Trefoil (Lotus corniculatus)
Oxeye Daisy (Leucanthemum vulgare)
Yellow Hawkweed (Hieracium caespitosum)
Meadow Buttercup (Ranunculus acris)
I bet you guessed. All these common roadside plants are exotics. They were introduced to North America and have never looked back.
Willow House Chronicles 
It’s amazing how many of our wildflowers we just take for granted. What grew at roadsides and in meadows before daisies and trefoil?
It is amazing. I think they are a bit like Starlings and House Sparrows though. Those birds mostly occur in town, where native species have more difficulty competing. Similarly, I think many exotic weeds occur in disturbed ground like roadsides for the same reason, although obviously, some are more widely distributed than others.
What mystifies me is why anyone would want to bring over Viper’s Bugloss. Ouch!
Go figure. Perhaps it was a stowaway, Waterjay.