$re = '/\](\d{1,2}\/\d{2}\/\d{4})\s([^\[]+)\[/';
$str = '[vc_row][vc_column width="1/1"]28/04/2015 Text description[vc_row][vc_column width="1/1"][vc_row][vc_column width="1/1"]29/04/2015 Text description 2[vc_row][vc_column width="1/1"]';
$subst = "<$1$2>";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php