I use worm castings on all of my plants: veggies, perennials, shrubs, trees, lawn, house plants, even my indoor catci. They all seem to benefit.

While it is always possible to overdo something, most plants would enjoy as much worm poop as you have to give them. If you are talking about an outdoor garden where you have mixed the castings into the soil, then you probably have not applied too much. Castings are very water soluble and will wash away fairly quickly, IME. I like to mix them with water to apply as a spoil drench in light doses over the season and use regular compost as a soil amendment to dig into my beds, but I don't think you have done anything wrong.

Your plants are all going to want the same garden loam with plenty of organic material (again, regular compost) except the blueberries, which require acidic soil to do well. Not sure where you are located, but if you are in SF, watermelons will want a hotter climate.

Good luck!