Here's the correct code for making recursive directories:

<?php

// function
function ftp_mksubdirs($ftpcon,$ftpbasedir,$ftpath){
   @ftp_chdir($ftpcon, $ftpbasedir); // /var/www/uploads
   $parts = explode('/',$ftpath); // 2013/06/11/username
   foreach($parts as $part){
      if(!@ftp_chdir($ftpcon, $part)){
         ftp_mkdir($ftpcon, $part);
         ftp_chdir($ftpcon, $part);
         //ftp_chmod($ftpcon, 0777, $part);
      }
   }
}

// usage
$path_of_storage = '/var/www/uploads';
$newftpdir = '2013/06/11/username';

$conn_id = ftp_connect($ftpserver);
ftp_login($conn_id, $login, $pass);
ftp_mksubdirs($conn_id,$path_of_storage,$newftpdir);
ftp_close($conn_id);

?>

When trying to user the ftp_mkdir, or ftp_chdir I've noticed that some servers like the entire path such as

/usr/local/home/username/sitename/directory/

and other servers, want you to use the path from the initial login, such as just /sitename/directory/

Just wanted to pass this on

For recurrent following function work better.
Some ftp servers (like WarFTP) become demented if you'll
try mkdir not from root dir and if path will be relative. 
The second if one of dir (like '/') already exist You'll get access denied. 

<?php
 function MkDir($path)
  {
   $dir=split("/", $path);
   $path="";
   $ret = true;
   
   for ($i=0;$i<count($dir);$i++)
   {
       $path.="/".$dir[$i];
       echo "$path\n";
       if(!@ftp_chdir($this->conn_id,$path)){
         @ftp_chdir($this->conn_id,"/");
         if(!@ftp_mkdir($this->conn_id,$path)){
          $ret=false;
          break;
         }
       } 
   }
   return $ret;
  }
?>

if(!@ftp_chdir($ftpcon, $part)){
         ftp_mkdir($ftpcon, $part);
         ftp_chdir($ftpcon, $part);
         //ftp_chmod($ftpcon, 0777, $part);
      }

This if part of answer below, if you want working chmod you need to replace it with:

      if(!@ftp_chdir($ftpcon, $part)){
         ftp_mkdir($ftpcon, $part);
         ftp_chmod($ftpcon, 0777, $part);
         ftp_chdir($ftpcon, $part);
      }