Eric,
Do your porterweed stalks have buds on them? I don't get a lot of flowers during the growing season on each stalk, but the hummingbirds love those flowers so much, that I try and plant at least one every year. "...ever gone without blooming for a few days?" Yes, I think the plants I've grown have.
Take a look at the pics on the website
Red Porterweed (Stachytarpheta mutabilis) and the general listing of porterweed plants with pics
https://garden.org/plants/brow...
Looking at some of the pics, I noticed that others get a lot more flowers on their stalks, so maybe I need to fertilize more.
I've never noticed any small crystal looking specks on the plants. The only time I've noticed any ants (as well as ant eggs) in my containers is when they've sat out for a few years (every day of each year) with potting mix in them, without being used for plants (I had to take all the potting mix out and add new mix before adding plants). They only time I've found ants on my plants is when I grew salvia oxyphora and the ants were on the flowers because of the nectar.
