If it is in a location where it can grow to its heart's content then I would leave it alone and, in Spring, I would prune any dead wood that does not leaf out by mid to late May or any stems that cross weird or grow "too much". That would be it for my pruning every year.

For that reason (when it is planted where it can reach its estimated size at maturity), you would expect no pruning of new & older shrubs since they are small and -assuming they were planted in a good spot- they will not be growing a lot and spilling onto other shrubs or walkways.

If your soil is not lacking on minerals, you would not need to fertilize. I sometimes do not because I run "out of time" to do it and it is not a problem. Mulch -when it decomposes- supplies minerals. And new shrubs usually already contain those round fertilizer pellets that will be 'just fine' in your first year.

If you want to fertilize in Spring, you can give them 1/2 to 1 cup of cottonseed meal, organic compost or composted manure and that is it for the whole year in your zone. If your winters were mild like mine and the shrub did not go dormant until December or later then a second application of zero/very low nitrogen fertilizer in the Fall would be ok. You can also use a slow-release, general purpose chemical fertilizer with a NPK Ratio of 10-10-10 or something close to that. If you want to keep busy, you can add some coffee grounds, liquid seaweed or liquid fish thru the growing season but, stop at the end of June so the plant will go dormant when it needs to and so it will not be on "grow mode" when winter arrives...

Some people like to deadhead the browned-out spent blooms immediately when they turn brown. Others do it in Spring so the blooms can be used for added winter interest. Other persons leave them on now and let Mother Nature take care of "removing them" in Winter/Spring. You can do any of these.

I couldn't have said it any better than Luis. I'll re-emphasize that you don't want to fertilize or prune new plantings. Give them at least a full growing season first, but if you don't see any issues and if there is plenty of room for it to grow, you don't need to do either, ever. Trim off spent blooms whenever you don't like their appearance, but that isn't really pruning. Mulching out to the drip line will even out moisture and temperature, and the breakdown of the mulch will provide nutrients to the plant slowly, at a rate that they can be absorbed.

Thank you both for responding. I made sure when I planted Limelight that I checked the maturity size to be sure each year it has more than enough room to expand. I did add mulch when I planted but want to add a bit more.

Go ahead with the plan then. I usually add some in the Spring and if I find good prices and have time, I will go around and add again in November-December.