its hard to tell you much of anything w/o a picture.. see link ... interior yellowing is normal ... increased by transplant .. and any other weather issue.. drought?? [before you got it] .. or improper watering after transplant ..... etc .. the fact that it is extending growth is a good sign ... no evergreen holds its leaves forever.. and again .. its the oldest that are shed.. which are the interior.. and it is increased by stresses .. like transplant.. ken Here is a link that might be useful: link

Putting Narture's Helper and topsoil around the base now won't help. That should have been done at planting, mixed with the original soil and then used as backfill for the large hole after you put the plant in. If they are dry, that's a whole lot better than too wet, so I'd water them and perhaps use just a little slow release fertilizer with minors, like Sta-green Nursery Special or Lesco 14-14-14 with minors. For hollies, an alternative is Espoma's Holly Tone, which has been used successfully for a long time.

If you're talking about 'Nellie R. Stevens' holly, it is not a native plant. It is a female hybrid plant, a cross between the English holly and the Chinese holly. Not sure what your friend meant, but generally you can get some 10-10-10 fertilizer (very common at Home Depot/Lowes) and just throw it out around the base of the plants.

i've found the easiest way to propagate holly's is to layer them. what cuttings did you put in the soil? the ones that were in the water or new ones? if you re used the ones that turned brown in the water then they're most likely dead. if you used new ones, what do they look like? you could still take cuttings from the live holly's and put them in a cold frame or pot them, bury the pot and then mulch really heavy.