Along the Wissahickon trail, upstream from the Henry Avenue Bridge, Solidago flexicaulis (with axillary inflorescences and wide leaves) is common, right by the trail, underneath the trees, on the way to Forbidden Drive.
Along the trail above, on the other side of the creek and up the hill in the woods, where it’s a bit drier, but still shady, Solidago caesia (with axillary inflorescences and narrow leaves) is common.
On the trail leading from Blue Stone Bridge, and leading along downstream (and up in the woods on the hill), both Solidago caesia and Solidago flexicaulis can be found.
In open areas, along the stream, Solidago gigantea (with smooth, glaucous stems) is very common; Solidago rugosa (with scabrous leaves) is also there. Underneath the Henry Avenue Bridge, there’s a thick stand of Solidago gigantea, and right next to that, there is an individual of Solidago rugosa.
Up on the hillsides, Solidago rugosa is the more common one in open areas.
Underneath a good sized (>2.5′ dbh) tulip poplar, just upstream from “Help Locator #125”, on the sunnier side of the tree there’s a robust stand of Solidago gigantea, and on the shadier side of the tree, there’s a robust stand of Solidago flexicaulis.
And so, overall, it appears that in this area, shady places that are moist have Solidago flexicaulis, shady areas that are drier have Solidago caesia, open areas that are moist have Solidago gigantea, and open areas that are drier have Solidago rugosa – and there is co-occurrence, in certain habitats.
Along the trail that goes from the white pines of Hermit Lane and passes under the Henry Avenue Bridge (and then goes onwards to Lovers Leap), there are no goldenrods along the trail, until after you pass beyond the bridge above.
NB: Eurybia divaricata (white flowers) and Eurybia macrophylla (lavender flowers) are both in flower – macrophylla appears to be at lower elevations than divaricata.