adding title to list subpages

I’m using this code to list my subpages but how can I add a title to it like, “subpages”? I tried just adding text in the
ul tags but it displays over the list which I’m floating left on a horizontal line.

<?php
  if($post->post_parent)
  $children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0");
  else
  $children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
  if ($children) { ?>
  <ul>
  <?php echo $children; ?>
  </ul>
  <?php } ?>