Darkseid76
Aquarium Advice FINatic
Dark, dry ferts (from what I'm told) are great for your rooted plants. Your wisteria won't gain anything from the tabs though. They need liquid ferts as they are not imbedded into the substrate. I have a 10 gallon planted with Moneywort, Red Wendtii, and Dwarf Amazon Sword Grass. I and currently using up my liquid ferts and then moving to dry. I wouldn't worry about iron as much as you think. Any kinda of plant that gives a red coloring will need Fe ferts. For plants without coloring, the iron in tap water from most WTP's use Feric Chloride to clean the water and your water will have a good amount of iron with just trace dosings. Just trying to give you more info so you don't spend too much money of ferts as they do get costly.
Oh, as I'm using the liquid, I found that injecting them directly into the substrate is working wonders for me. I dose trace and iron once a week and CO2 5 out of 7 days (actually I double dose the beneficial CO2)
The only plants that aren't thriving are my dwarf sag, corkscrew vals and a tiny piece of Cabomba furcata. I don't have any wisteria. You must be referring to my water sprite which I'm most definitely not having a problem with lol