diff --git a/src/Collection.php b/src/Collection.php
index 2dd26df..118c911 100644
--- a/src/Collection.php
+++ b/src/Collection.php
@@ -64,7 +64,7 @@ public function toTree($root = false)
 
         /** @var Model|NodeTrait $node */
         foreach ($this->items as $node) {
-            if ($node->getParentId() == $root) {
+            if ($node->getParentId() == $root || ! $node->getParentId()) {
                 $items[] = $node;
             }
         }
@@ -140,4 +140,4 @@ protected function flattenTree(self $groupedNodes, $parentId)
         return $this;
     }
 
-}
\ No newline at end of file
+}