Barring any weird, specific deficiencies, the Mill's Magic should be fine. Remember, even most modern "artificial" hybrids are generally successful left alone to their own devices as long as they receive the minimum they need to survive. Adding extra fertilizer, provided the amount, type, drainage, irrigation/rain, and situation are appropriate, should only serve to make them more productive and potentially healthier. The worst we often do is "kill them with love". Kim

It also depends on how good your soil is. Here in hot dry SoCal where I found the soil to be terrible the only answer is to build it up as much as possible. This means piling on the mulch year after year. I did this in CT and after 10 years or so almost nothing was required. No need to feed or even water most years.

I had a soil test done and it showed our soil already was rich in most nutrients so I usually just top dress with wood mulch & cow manure once a year or every other year.
Now I do have slight Nitrogen problems which I correct with some Alfalfa Meal when needed...

So its hard to tell about different soils unless a soil test is done.

Jim, I define good soil as rich dark humus at least one foot deep and eventually up to two feet deep. You can't get this unless you make it and once you do you don't need to make soil tests.