Musk Thistle
Q: I have a beautiful weed growing in my yard. The base of the plant has been growing all winter. It has very sharp thorny leaves. In the last month it has grown at least four feet and has a burgundy flower at each elbow. The flower at the top is feathery and blows in the wind.
A: You have a musk thistle, Carduus nutans. Despite the pretty flower, it is a weed. It will spread by seed and infest your flower beds. It’s interesting to know that it is a biennial plant. Only the ground-hugging rosette of leaves grow during the first year. The following spring a tall flower stalk emerges, bearing the flower you like…plus hundreds of seeds.
I recommend you dig it out or spray with herbicide.