Get value out of unknown PropertyInfo

I am trying to get the value out of a PropertyInfo without knowing what type it is at runtime.

private TreeViewItem processObject(string h,PropertyInfo o)
    {
        TreeViewItem root = new TreeViewItem();
        root.Header = h;

        Type myType = o.PropertyType;
        IList<PropertyInfo> props = new List<PropertyInfo>(myType.GetProperties());
        foreach (PropertyInfo prop in props)
        {
            Type subType = o.GetType();
            TreeViewItem sub = new TreeViewItem();
            sub.Header = prop.Name + " : " + prop.GetValue(subType, null);
            root.Items.Add(sub);
        }

        return root;
    }

I am unsure of what yo pass into the prop.GetValue method in order to get out its value