Backyard botanical

I was doing my thrice-daily rounds near the Concentric Garden when I noticed some intriguing plants at the edge of the property. I pulled out a whole lot of invasive garlic mustard from that area in May. Now it's overgrown with as-yet-unidentified native plants, blackberries, buckwheat (that I planted to replace the mustard) and grasses.


As I took a closer look at the plant that first caught my eye -- it's milkweed -- I noticed another specimen with spearheaded leaves and star-shaped, purple flowers. "Must be some kind of nightshade," I thought.

"Woody nightshade (Solanum dulcamara) is also known as bittersweet nightshade, felonwood, and felonwort. In the Middle Ages, the name dulcamara was written more properly as Amaradulcis, literally meaning 'bittersweet.' Felonwood and felonwort are not as sinister as they might sound; 'felon' is not referring to criminals, but rather to whitlow, which is an inflammation of the toe or finger around the nail.

"Woody nightshade was used for many medical conditions, including dissolving blood clots (in bruises), for rheumatism, fever, and as a restorative. Farmers used it as a charm around the necks of animals they thought to be under an evil eye. Ripe bittersweet berries are red rather than black, as seen with deadly nightshade (Solanum nigrum)."

While I poked around in the back, I saw several plants that I thought could be poison ivy or poison oak. Unfortunately, the rule of "leaves of three, let it be" didn't seem that handy since blackberry and other plants have similar leaf structures. Some online examples that I saw were contradictory. And apparently, Virginia creeper looks like poison oak. So can you tell me what's what with the following photos?