Fertilizers for specific crops is pure marketing. The important thing is the ratio of fertilizers on the bag versus what is in the soil.
The best way to save money, use fertilizers responsibly, and prevent environmental damage is to do soil test. Then apply fertilizer based upon the results.
In Potted plants it is a bit different. You need to provide all of the nutrients for the plant and then leach out salt buildup. Use of slow release fertilizer with a ratio of 3:1:2 (NPK) plus micros is needed.