This is a question about the origins of life, and the answer depends on what you mean by "man" and "plants".

Here's a breakdown:

* Scientifically: Life on Earth evolved over billions of years. The first single-celled organisms appeared about 3.5 billion years ago. Plants, specifically multicellular algae, evolved much later, around 1.2 billion years ago. Humans, as a species (Homo sapiens), evolved much more recently, about 300,000 years ago. So, in this sense, plants existed long before humans.

* Religious beliefs: Many religious texts, like the Bible, describe a creation event where humans were created before plants. These accounts are not based on scientific evidence and differ greatly from the evolutionary understanding of life's history.

In summary:

* Scientifically: Plants evolved long before humans.

* Religiously: Different creation stories have different accounts of the order of creation.