Pesto is nutty and often has a hard cheese added, using olive oil. Salsa Verde has an element of brine with capers or anchovies and also a small amount of vinegar added. Chimichurri has vinegar and chilies added. The leafy herbs can vary as can the consistency and where they are used.
The temptation when faced with a new recipe and missing ingredients is to just mix them up a little. However with a bit more understanding of what each spice brings to a dish you can decide how to replace and substitute with a bit more expertise.
For anyone who loves a curry it is great to be able to grow your own ingredients, even if you live in the UK and colder climates!