Question
I have just planted 20 5 gal size Leyland Cyprus bushes. I would like to know the proper fertilizer and the application.

Answer
A slow, gentle Time-Release fertilizer that amounts to a Soil Amendment would provide optimal nutrition for your new Cypress collection.  Cheap, common fertilizers sold in large bags with megadoses of minerals are not going to work in their favor.

You want to tilt the soil chemistry in your favor.  You want to direct microorganisms to generate nutrition at the perfect pace, adjusted by temperature and moisture, just like they would in Nature.  This is especially important when you are talking about large shrubs or Trees like yours.

Organic fertilizers are the ideal, original slow release fertilizer.  The 18 Rule applies here.  Add up the N-P-K on the bag of fertilizer.  If the sum is 18 or less, you're in business.

The nutrients are derived from Manure, Fish Emulsion, Bloodmeal, Kelp or Seaweed, Alfalfa or Cottonmeal, Greensand and a long list of others.  Compost and Humus are packed with Organic Matter that builds great Soil.

The best organic fertilizers raise populations of soil microbes.  Instead of dousing the roots for a few seconds in quick-evaporating Urea Nitrogen fertilizer, say, the microbes generate a constant supply of minerals, over a very long period of time, converting the fertilizer into the perfect form of Nitrogen for the plants while adjusting the pH and supporting other complex biochemical activities that we are still trying to understand.

A top dressing of Compost and leaf mould in autumn will break down through the Winter.  Through the Summer, it will work with your Fertilizer to build leaf growth.  A high Nitrogen Fish Emulsion or Bloodmeal application would be a well timed Spring feeding.

For now, IF your soil is low in Phosphorous, a high-Phosphorous amendment is called for, the best known being Bone Meal.  Note that some parts of the country are known for Soil that is already HIGH in Phosphorous -- parts of the West plus a strip along the Northern U.S.  You would need a Soil test to know that. Deficiencies show up in Soil down South.  If you have a largely Clay soil, or if the pH is too low or too high, or if you have too much Iron or Aluminum in your Soil (either naturally or because you used too much Ironite etc), Phosphorous will be locked up and unusable.  This is why a Soil Test is a critical part of EVERY gardening project, whether you are planting a Tree or growing a Lawn or tending your Roses.  Everything begins with the Soil.

If you would like to give me your Zipcode or nearest City, I can zero in on the local Cooperative Extension to see where they are sending Soil Tests these days in your area.  Then you'll have a clear picture of what you are using as a growing medium for this investment, and have a much sharper plan for them.  Thanks for writing.