Have you had a professional soil test done? If not, there is no way to know what specific nutrients - if any - may be required.

If you just want to cover your bases, then any all purpose fertilizer will work. These typically will have all 3 NPK numbers the same - 10-10-10, 4-4-4, etc. And come in both dry granular or water soluble formulations. Also, generally the synthetics will have the higher ratio and be fast acting and organics the lower ratios and a slower release of nutrients.

Apply when you see new growth starting to develop, ie. this season's leaf buds.

btw, cross-posting to the Ask the Yard Doctor forum will prohibit anyone on the GardenWeb portion of the platform from responding. That is a defunct forum that only allowed responses to be made by the unknown "Yard Doctor" and so cross-posting there restricts what sort of responses you might receive. Most of the serious gardeners are on the GW side, not on Houzz.

Look at an independent garden center for "Evergreen Food" or similar labeling.

@gardengal48 is there an organic brand you like? How much would I need for about 100 linear feet of hedges spaced about three feet apart? What shoud I expect to pay for that?

I would remove "Ask the Yard Doctor" but the lovely features of this website do not let me edit my own posts after a short timeout period.

Either Espoma or Dr. Earth would be brands I'd favor and both should be available in your area. If Espoma, I'd pick their Plant Tone or Holly Tone (good for any BLE) or the Dr. Earth All Purpose. Apply according to label directions. for established plantings.

I seldom have found the need for fertilizing anything other than containerized plants so I can't quote price specifics. But in general, organics tend to be more expensive than the synthetics.

The only plants that i fertilize (in the ground - containers are a different story) are roses. i buy alfalfa pellets at the feed store and throw handfuls around them. Now this is practically pure nitrogen; if you are looking for a balanced fertilizer it won't do the job. But it's cheap and easy and the roses perform beautifully.

@gardengal48 do you have any opinion on how many pounds of fertilizer would cover a 100 foot length of hedge spaced about three feet between shrub? My gardener thinks four pounds will do but I suspect more is needed.

Do you have any thoughts on whether this should be mixed into the soil thoroughly or whether it could just be sprinkled on top? Probably rains for this year are about over here.

westes, different types of fertilizers will have different application rates. And recommended application methods. You have to read the labels.

@gardengal48 For example, the Dr Earth product says use one cup for every one inch of trunk diameter, for a mature tree. For a four foot high shrub with a two-inch diameter, that implies two cups of fertilizer per plant. It strikes me as a huge amount of fertilizer to use. But those are the written guidelines. I was thinking that you might know - from experience - that those instruction labels just try to make you use the maximum of fertilizer, when maybe 1/3 the amount would still give a similar result. Would you use that much fertilizer per plant?

Miracle-Gro 1001233 All Purpose Plant Food is a good option!

@gardengal48 You made the point that Holly Tone fertilizer is good for any "BLE". What does that acronym stand for?

Broad Leaved Evergreen - plants like boxwood, holly, rhododendrons and azaleas, etc.

Sara Malone!! Glad to see another champion of alfalfa meal....it's magic!