I tried Osmocote 14:14:14 on some LSU purple seedlings I received, to see what would happen.  I put the fertilizer in the top inch of my pot, and put none in another pot.  Here are the results after 2 weeks (the one on the left had the Osmocote).

 

It could be other factors, but they started exactly the same size and are in pretty similar pots.  I had a third without fertilizer as well, and it is similar to the one on the right.

Bill from Bill's fig farm uses Osmocote 14-14-14 on all his trees

That's what I use. Has made a huge difference. In hot rainy weather apply every month or so as it will break down much faster.

I've had great luck with Osmocote on all of my plants.  My figs were pretty blah until I added osmocote.  Within a few days they were growing very well.  

In my larger trees I have been giving them some foliage pro once a week.  I mix one tbsp into one gallon, and give 2 cups of water to each tree after I having previously watered 1 hour ago.  So far they seem to be doing well.

I wonder if that is considered a lot or a little, because while the concentration is higher than recommended, it is only two cups (not much for a 10 gallon pot).

https://icl-sf.com/uk-en/products/ornamental_horticulture/8733-osmocote-pro-3-4m/

While this does make a case that any fertilizer is better than nothing this would be a much better test if it was fertilize 10 plants with A, fertilize 10 plants with B and do not fertilize group C. Keeping all plants even this would lead to a valid conclusion. It has been shown that container bound plants tend to use nutrients in a 3-1-2 NPK fashion. If that is correct eventually you would have an overabundance of P in the soil causing problems in nutrient uptake. That being said some nurseries do use 10-10-10 because it is very cheap and they are usually applying to in ground plants which don't have salt problems to the same extent that container plants do, especially SIPs. If 14-14-14 is better than nothing that is great and if you water heavily the salts may be flushed out. Don't assume though that essentially 1-1-1 is the ideal ratio. 

Adipose, I would venture that the way you are using Foliage Pro is not ideal. You have very high nutrient water getting mixed unevenly into the soil at much higher than recommended concentrations. 1/4 teaspoon per gallon is considered maintenance and 1 teaspoon per gallon is very heavy feeding. Is this still how you use FP?

Yes plants need fertilizer, they eat just like us. The test also depends on what's in your soil. For example I add 1 part compost and the difference might not be noticeable since they are already being fed a touch. I agree with livetaswim06. 3-1-2 NPK ratio is just about ideal. Why I use Dynamite slow release that has a similar NPK ratio (15-5-9). Don't forget your trace elements!  Foliage Pro and Dynamite have micros. I use both on plants, but Dynamite is nice as it is slow release, also lasts 9 months, not 6 months. Which in hot weather cut in half. I also hit them once a month with some organic fertilizer. One of the tones usually, Tomato-Tone, Plant-Tone, Garden-Tone, Holly-Tone, etc.

That is what I use and it works great!

I use Osmocote plus in all my trees. It makes a huge difference in terms of growth and healt. Osmocote Plus has micronutrients.

The Osmocote Plus is a 15-9-12 formula.

I haven't ever seen apex available for sale, but it sound interesting. About half their formulations stick to the 312 npk that I like. Where are their products available?

http://www.simplot.com/turf_horticulture/apex/distributors

Might be able to find it here.

The plant on the left received Osmocote while the plant on the right received nothing?  Am I understanding this correctly?