A few days ago, the meadow (at least parts of the meadow) turned yellow again, this time when the goldenrod seemed to come into bloom all at once. The meadow was last looking this yellow in the spring, when the yellow hawkweed was in bloom everywhere. Goldenrod adds nice colour, but it is allelopathic, meaning its roots put out chemicals that discourage the growth of other plants. It tends therefore to be a tough, self-sustaining weed. On the other hand, it is a host for a number of beneficial insects, including some butterflies.
The entire bloom on a goldenrod is actually made up of hundreds of tiny florets that you almost need a magnifying glass to see. This is just one frond in a bloom that may have a dozen yellow fronds. People often mistake goldenrod for ragwort, a common cause of hay fever.
Another interesting yellow plant is the very tall elecampane, its flower a beautiful yellow sunflower type, with very small but bright yellow rays.
It has huge leaves, perhaps the largest of our native meadow plants, and stands up to 6 feet tall. It likes to grow in wetter corners, where the soil is damp at least in the spring, so it's only found in wet meadows.