In an earlier version of this article, we misidentified this as the native Virgin’s Bower (Clematis virginiana). That is a very similar relative; this plant is the Asian Autumn Clematis (Clematis terniflora), which is becoming more and more common along fences and twining through hedges in the city.
For a description of the species, see the Clematis terniflora reference page.
These tropical garden escapes seem to love the Pittsburgh climate. They can cover whole hillsides or fences with twining vines that produce heart-shaped leaves, or sometimes three-lobed grape-like leaves when they really get large and vigorous. The flowers close by noon, giving us one of our best incentives for early rising.
No photograph can convey the vivid purple color of ironweed, one of our most spectacular late-summer flowers. A field of ironweed and goldenrod is a sight not easily forgotten. Two species are common in our area; Tall Ironweed is, as its name implies, taller than New York Ironweed (Vernonia noveboracensis), but otherwise very similar.
Wherever there are hillsides that no one wants to mow, there is crown vetch. Its cheerful vigor means that it often escapes and invades a hillside on its own, but its happy clover-like pink flower heads make us willing to forgive its bad manners.
This common and poisonous little member of the tomato family grows in vacant lots, at the edge of the sidewalk, and anywhere else it can gain a foothold. Up close, the little white flowers with bright yellow centers are cheerful and pretty.
