Had to do this for a project recently. If you've any experience with FTP you'll know it's not the most efficient of protocols. If you want to make changes to a file or folder you have to deal with each file individually.

In the case of removing a folder, you have to first make sure that it's empty and in order to do that you have to loop through each file and delete each one in turn.

Wanted to keep note of it somewhere and figured here was as good of a place as any!

function removeFolder($ftpConnection, $path) {
	static $log = "";
	$contents = ftp_nlist($ftpConnection, $path);
	if(!$contents){
		// Nothing in the folder
		ftp_rmdir($path);
		$log .= "Removed {$path}";
	} else {
		// Loop through each of the files
		foreach($contents as $currentFile) {
			if($currentFile != "." && $currentFile != "..") {
				// Assuming it's a folder and there's no dot in the name
				if (strpos($currentFile, '.') === false) {
					// It's a folder, so call itself
					removeFolder($ftpConnection, $path."/".$currentFile);
					// Once all files are gone delete the folder
					ftp_rmdir($ftpConnection, $path."/".$currentFile);
				} else {
					// If it's a file delete it
					ftp_delete($ftpConnection, $path."/".$currentFile);
				}
				$log .= "Removed {$path}/{$currentFile}n";
			}
		}
		ftp_rmdir($path);
	}
	return $log;
}