DOMDocument code generating malformed XML.

malformed_domdocument.php

<?php
$plantList = $this->em->getRepository('Entities\Plant')->toGoogleProductsFormat();        

	$xml = new DOMDocument('1.0', 'utf-8');
        $xml->formatOutput=true;
        $rss = $xml->createElement('rss');
        $rss->setAttribute('version', '2.0');
        $rss->setAttribute('xmlns:g', 'http://base.google.com/ns/1.0');
        $rss->setAttribute('xmlns:c', 'http://base.google.com/cns/1.0');
        $xml->appendChild($rss);
        
        //Create channel element
        $channel = $xml->createElement('channel');
        $channel = $rss->appendChild($channel);
        
        //Loop through each plant
        foreach($plantList as $plantItem){
        
        	//begin item element
        	$item = $xml->createElement('item');
	      	
	      	
	      	//Loop through use key as element name and value as data
	       	foreach ($plantItem as $key => $value)
		    {
		    	//Decode HTML characters, for example '&' becomes  &
			    //to comply with http://www.w3.org/TR/xhtml1/#C_12
		  	    $decode = htmlspecialchars_decode($value);
		  	    $decode = trim($decode);
		  	    
			    if(empty($decode))
			  	  continue;
	        
		    	//Create the element
			    $tag = $xml->createElement($key);
			    $tag = $item->appendChild($tag);
			    
			    //Write the field
			    $text = $xml->createTextNode($decode);
			    $text = $tag->appendChild($text);
			    
		    }
		    $item = $channel->appendChild($item);
	    }

        
        //Output xml to body
        $output = $xml->SaveXML();
        
        //Validate
        $validator = new XMLValidator($xml);
        
        $this->_response->setHeader('Content-Type', 'text/xml; charset=utf-8')->setBody($output);