They do put on a constant show of flowers and are capable to doing well in the shade....an idea if your efforts are for UK summer pots?! You sound like a wonderful Fairy Godmother for those who tend to neglect their pots and plants. In lots of heat and daily sunshine, the pot plants would probably need watering every day, and in very hot weather probably twice. If this is not happening, you could get over this, maybe, by putting some water retaining gel beads in the pots when planting up and when you do a drive-by watering, maybe every other time mix up some Miracle Gro feed in the water. Total magic for plants, they double in size and vigour very quickly, they also soon revive with a drink of that if they are looking neglected. (And it goes a long way and is not expensive). Have a look at maybe, Verbena, Callibrachoa (Million Bells) Perovskia (Russian Sage) Lavenders, Astilbe, Lobelia, Marigolds, Nemesia, Vinca (not the trailing one) Pelargoniums/Geraniums and certainly Impatiens, both the New Guinea and the smaller varieties and Salvia Farinacea "Alba" and "Victoria" - white and purple. A large number of these don't need lots of dead-heading! Hope your efforts are appreciated