XML without root in Linq Select

I have an Index view where I would like show a list of news article, the Text property is a string which contains a html string coming from a html editor; now the html content could be really long, so I would like show only the first <p> element. I am doing that:

public ActionResult Index()
    {
      var articles = db.Articles.ToList().Select(a => new{Title = a.Title, 
                                                          Tags = a.Tags, 
                                                          Id = a.Id,
                                                          Text = (System.Xml.Linq.XDocument.Parse(a.Text).Descendants("p").FirstOrDefault())
                                                          }).ToList();

      return View(articles);
    }

But in the html string there is not a root node, so the Linq query fall in exception, How I can manage this case?

Thanks in advance for any suggestion