Before doing anything have that soil tested to see what, if anything, might be needed. Simply throwing some "fertilizer", even compost, may create more problems then if might cure.
What is that soils pH?
Are the plants growing pretty well?
Are the plants bothered by a lot of insect pests?
Are those plants infected with some diseases?
An unbalanced soil, wrong pH for the plants, excess od deficient nutrient levels can result in plants that have growing problems.

Thanks for the reply, kimmsr. I frequently hear that recommendation, "get a soil test," but our local cooperative extension won't do them. The ironic thing is it's U.C. Davis, known for their agricultural program. :/ So I wind up with the cheesy soil tests you pick up at the big box stores that don't seem to tell me much.

While your UCCES does not do soil testing they can supply you with a list of labs that do or the University of Connecticut (UCONN) or the University of Massechussets (UMASS) have tested soils from other states so it may be beneficial to look at their websites.

If you were to opt for a layer of compost before the bark mulching, there is no need for a soil test. For many years, I mulched ALL my planting beds with compost - no more than 2-3 inches annually - and everything thrived. I preferred using compost as mulch because of the texture and appearance and so I could avoid any other supplemental fertilization.

While there are valid arguments to be made towards not fertilizing unless nutrient deficiencies exist, these can become present rather easily. For example, nitrogen is often lacking in cultivated soils due to its extreme mobility. Combine that with a nitrogen-tying woody bark mulch and the relatively shallow root system of most perennials or annual flowers and nitrogen supplementation is often advised. This is typically much less of an issue with well-established and deeper/wider rooted plants like trees and shrubs.

Compost used as a mulch is pretty hard to overdo with the fertilzing aspect and a reasonable layer will most certainly NOT create additional problems. Except for being a rather fertile seedbed for windblown weed seeds :-) But a layer of bark mulch over the top will reduce that issue.

Its a natural healing to get rid of skin diseases and is used in India. Because of busy schedule we can't manage for such treatments.T However, today we have number of natural products available in market that help us to get the same results. The products from world organic are very helpful these days as they have total natural ingredients. Its helpful, really.

Here is a link that might be useful: Natural Skin Care Routine

Cultivated soils lacking Nitrogen usually are also lacking adequate levels of organic matter so people throw some form of highly soluble N at that soil and it is washed out with the water flow and pollutes the ground water which eventually reaches our drinking water.

Here is a link that might be useful: The Nitrogen cycle