diff --git a/dask_expr/_merge.py b/dask_expr/_merge.py
index fa15a9e6..df782304 100644
--- a/dask_expr/_merge.py
+++ b/dask_expr/_merge.py
@@ -50,6 +50,10 @@ class Merge(Expr):
         "shuffle_backend": None,
     }
 
+    def __init__(self, *args, _precomputed_meta=None, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._precomputed_meta = _precomputed_meta
+
     def __str__(self):
         return f"Merge({self._name[-7:]})"
 
@@ -70,6 +74,8 @@ def kwargs(self):
 
     @functools.cached_property
     def _meta(self):
+        if self._precomputed_meta is not None:
+            return self._precomputed_meta
         left = meta_nonempty(self.left._meta)
         right = meta_nonempty(self.right._meta)
         return make_meta(left.merge(right, **self.kwargs))
@@ -105,7 +111,9 @@ def _lower(self):
             or right.npartitions == 1
             and how in ("left", "inner")
         ):
-            return BlockwiseMerge(left, right, **self.kwargs)
+            return BlockwiseMerge(
+                left, right, **self.kwargs, _precomputed_meta=self._meta
+            )
 
         # Check if we are merging on indices with known divisions
         merge_indexed_left = (
@@ -166,6 +174,7 @@ def _lower(self):
                 indicator=self.indicator,
                 left_index=left_index,
                 right_index=right_index,
+                _precomputed_meta=self._meta,
             )
 
         if shuffle_left_on:
@@ -187,7 +196,7 @@ def _lower(self):
             )
 
         # Blockwise merge
-        return BlockwiseMerge(left, right, **self.kwargs)
+        return BlockwiseMerge(left, right, **self.kwargs, _precomputed_meta=self._meta)
 
     def _simplify_up(self, parent):
         if isinstance(parent, (Projection, Index)):
@@ -240,8 +249,13 @@ def _simplify_up(self, parent):
             if set(project_left) < set(left.columns) or set(project_right) < set(
                 right.columns
             ):
+                columns = left_on + right_on + projection
+                meta_cols = [col for col in self.columns if col in columns]
                 result = type(self)(
-                    left[project_left], right[project_right], *self.operands[2:]
+                    left[project_left],
+                    right[project_right],
+                    *self.operands[2:],
+                    _precomputed_meta=self._meta[meta_cols],
                 )
                 if parent_columns is None:
                     return type(parent)(result)
@@ -277,17 +291,7 @@ def _lower(self):
 
     @functools.cached_property
     def _meta(self):
-        left = self.left._meta.drop(columns=_HASH_COLUMN_NAME)
-        right = self.right._meta.drop(columns=_HASH_COLUMN_NAME)
-        return left.merge(
-            right,
-            left_on=self.left_on,
-            right_on=self.right_on,
-            indicator=self.indicator,
-            suffixes=self.suffixes,
-            left_index=self.left_index,
-            right_index=self.right_index,
-        )
+        return self._precomputed_meta
 
     def _layer(self) -> dict:
         dsk = {}
diff --git a/dask_expr/io/parquet.py b/dask_expr/io/parquet.py
index 20b15514..7d5a4f6b 100644
--- a/dask_expr/io/parquet.py
+++ b/dask_expr/io/parquet.py
@@ -557,7 +557,7 @@ def _dataset_info(self):
 
         return dataset_info
 
-    @property
+    @cached_property
     def _meta(self):
         meta = self._dataset_info["meta"]
         if self._series: