PHP mailer - include path when folders are outside root

PHP mailer - include path when folders are outside root

i had phpmailer running fine on a hosted server. I moved to a VPS which is
linux/ubuntu so most of the installation is done via the console.
Previously my include was simply
include('phpmailer/class.phpmailer.php');
include('phpmailer/class.smtp.php');
Both those were inside the root folder, when i ran the install via the
console it stored the files in usr/shar/php/libphp-phpmailer
Ive never worked with files outside the root, is there a special way to
reference them when using includes?
for reference my root folder is var/www/