You don't say how you prepared the soil, what the conditions are of the area they are planted (under trees, in a shade garden with other perennials, etc.) or where you live.* Coral bells are woodland plants, and although they like moist soil, watering daily is probably what is wrong.* Unless you live in the desert and are planting in sand or there are masses of tree roots, you should water deeply once a week if you don't get an inch of rain.* Just stick your finger into the soil up to your second knuckle.* If the soil is moist, you don't need to water.
I'm not sure what deco rock is, but if it's large and heavy stones they could be compacting the soil.
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.