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Multiflora Rose Rosa multiflora
It was planted by some transportation departments along roads as a crash barrier. I don't know if it stops a crashing car or whether a careening car avoids it because of the thorns! Another supposed virtue was its ability to attract wildlife. The fruit (technically rose hips) are colorful and apparently tasty in the spring and attract wildlife, tricking them into spreading its seed everywhere a bird can poop.
"Multiflora rose reproduces by seed and by forming new plants that root from the tips of arching canes that contact the ground. Fruits are readily sought after by birds which are the primary dispersers of its seed. It has been estimated that an average multiflora rose plant may produce a million seeds per year, which may remain viable in the soil for up to twenty years. Germination of multiflora rose seeds is enhanced by passing through the digestive tract of birds" DCNRMore information is at the Plant Conservation Alliance "Least Wanted" site.