Manufacturers have increased the variety of genus specific fertilisers.
At one time variations on the proportion of NPK was enough with Fish, blood, hoof, horn and bone and Growmore amongst the staples. Rose food, ericaceous plant fertiliser and seaweed extracts were then made available with the allegedly all too necessary ‘trace elements’. Good husbandry will replace most Plant specific fertilisers if you follow the basics.
Orchid feed and cactus food were amongst the next batch of prepacked products. Then Citrus plant special fertiliser became a ‘necessity for the millions who grow Oranges and Lemons (although special packs for winter and summer fertiliser seems another step too far.’
Now the choice is wider still with Fuchsia fertiliser, Clematis food, Onion fertliser, Potato fertiliser all prepacked for the ‘gullible gardener.’
Bonsai food and Palm fertiliser are available from Chempak which is now owned by Thompson & Morgan as are Orchid growth and Orchid bloom food. Baby-bio Orchid feed is identical to baby-bio normal except it is watered down by 50% and packaged in a different colour.
Peonies and a special Peony fertilizer from Thompson & Morgan.
The only specialty feeds I use are African Violet and Tomato fertiliser