Prior to Linnaeus (as seen above), nomenclature was an unwieldy mess. There were plenty of folk taxonomies that had organically grown out of each culture’s unique linguistic connection to their local landscape. Many of these taxonomic systems had significant overlap with scientific taxonomies, particularly at the level of genus, but there were often discrepancies across the various systems (the Navajo, for example, lumped spiders in with birds and bats as flying beasts). With all those systems, each species invariably had multiple common names (see, for example, link), and a single common name might be applied to entirely unrelated species (as with the cedars).
A folk taxonomy is fine when you’re dealing with just your local plant and animal species (the average folk taxonomy typically includes about 600 plants – link; Carol Yoon’s book on taxonomy suggests that people can generally recall a list of about 600 things, whether they’re the names of bands, beetles, or books). But as naturalists scattered far and wide, collecting thousands and thousands of new specimens from thousands of new species (Alfred Russel Wallace alone sent over 100,000 specimens representing hundreds of species back to Europe from his travels abroad), it became increasingly difficult to keep track of all that biodiversity and to communicate clearly about a species across cultures and languages. Linnaeus arrived just at the time when a more rigorous, universal taxonomy was essential for the natural sciences to develop.