It depends. For the most part, the two are actually unrelated. Comfey, for example, simply likes to collect flowers and does so in the way that’s most efficient for its species. Leis, meanwhile, come from a rich cultural background that has less to do with comfey and more to do with the tapu.
On the other hand, sometimes, objects are indeed tied to pokémon or vice-versa. For example, punching bags were absolutely inspired by the wobbuffet line (right down to their general shape), and if you believe in certain ancient legends, many languages were based on unown shapes. (The modern-day language of Common also based its writing system on unown markings, which is why many of our letters seem blocky and thick.) Conversely, sometimes, objects come before the pokémon, especially in the case of many ghost-types, which tend to inhabit objects. (Banette, the honedge line, and dhelmise are all examples of this.) Then of course, you have the voltorb line, which looks the way it does because of an object, but it’s more because an accident or other strange happening involving said object led to the creation of the pokémon.
Alternatively, some pokémon appeared much later in time, and scientists theorize that these pokémon actually adapted themselves to look like inanimate objects in order to better interact with humans. The drifloon line, for example. Or the trubbish line for an example that doesn’t involve consuming the souls of the living.
The Pokédex According to Bill 