I took a walk through my 22-acre pasture yesterday to see how it was faring in the drought. For the most part, it was a sea of brown. On the south slope were random spike-like weeds jutting up 5 feet with velvety leaves and yellow flowers. I took a photo and posted it on Facebook, where a friend identified it as Common Mullein (Verbascum thapsus).
This weed starts as low-growing rosettes the first year (I saw some of those, too) and then grows as tall as 10 feet the second year with a flowering stalk. An established population of common mullein can be difficult to eradicate, and the weed is classified as noxious in Colorado and Hawaii. Bob classifies anything the sheep and goats won't eat on our farm as noxious.
Here is another example of a plant not native to the U.S. being brought here to solve one problem and then causing another. Common mullein was first introduced into the U.S. in the mid-1700's as a medicinal herb. It quickly spread throughout the U.S. A single plant can produce 100,000 seeds which may remain viable for 100 years in the soil.
We are seeing it spike up this year because we didn't mow the pasture as normal, due to lack of rain. I cut as many of the hard stalks as I could (it was 95 degrees, so I didn't stay long). My sharp clippers could barely do the job. But it was a worthless job, I found out, because I left the blooms and seed capsules on the ground. I should have bagged them and sent them to a landfill.
When I posted this photo, a farmer friend said the real weeds are in the distance -- they multiply rapidly, and are very invasive!