I think you've answered your own question.* You said you have them in rich soil and water them everyday.* They do like moist soil, but not wet soil.* Overwatering can cause wilting too, so unless you just planted them in the last couple of weeks and it's over 90*F, I'd say to water when the soil starts to dry.* If they are established they will do just fine, especially in rich soil which retains moisture.*
We have had barely any rain here in 3 months and I haven't watered my Lobelia cardinalis aka Cardinal flower at all and they're doing just fine.* They've been in the ground for 5 years now.* My Lobelia siphilitica aka Giant blue lobelia is under a tree and in competition with tree roots.* I've only watered them once and they're getting ready to bloom now.* They self seeded in that location also 5 years ago.* Stop watering and I'd bet they perk up.* :)
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.