diff --git a/pyogrio/geopandas.py b/pyogrio/geopandas.py
index 2f9be6ac..1cbcb113 100644
--- a/pyogrio/geopandas.py
+++ b/pyogrio/geopandas.py
@@ -50,7 +50,7 @@ def _try_parse_datetime(ser):
         try:
             res = pd.to_datetime(ser, **datetime_kwargs)
         except Exception:
-            pass
+            res = ser
     # if object dtype, try parse as utc instead
     if res.dtype == "object":
         try: