How to assign textarea value in non-form using Symphony\DomCrawler?

I am doing functional unit test for Silex based application.

I am able to select textarea nodes using:

use Silex\WebTestCase;

$textarea = $crawler->filter('[note-for="'.$cart->id.'"]');

This returns Symfony\Component\DomCrawler\Crawler Object. I would like to assign value to this textarea. This textarea is not in a form tag.