I'm sure others will add opinions, but my take on it is that I notice my different varieties have slightly different leaf color. Certainly the Indigo Rose has an unusual coloration, quite "blue green," so I wouldn't look to compare that to the others. So, it could just be that.

Or, it could be the soil, for sure. Some people find they have better success in the ground, and some better success in containers, depending on their garden soil.

On watering, I am no expert at in-ground watering, but it sounds to me like you are watering shallowly. I hear it is better to water more deeply and less often. You could, for instance, use a soaker hose, and run it for 30-60 minutes to get water a foot or more down in the soil. This will promote much better root growth and plant health.

It's also better to water based on the actual state of the soil that day, rather than an arbitrary schedule. Feel the ground with your finger (or a bamboo skewer or wooden chopstick, which can go deeper) and water when the soil is getting dry. Doing this will teach you how much water it takes to moisten the bed deeply, and also, how long your soil stays moist after a good watering.

Jenn

PS: Pictures would help! They are easy to post here.

Yeah, different varieties have different shades of green.
---Indigo Rose has almost purple foliage. It matches the color of its fruits.
-- Black from Tula, Black Cherry, Red Cherry ... have dark green color, so does Ananas Noire.
-- CP, Big Rainbow, KB, 4th O July , Polish Dwarf .. are pale green.
Just to name a few .
You can see them growing in the same bed, side by side.

Sey