diff --git a/mllib/src/main/scala/org/apache/spark/ml/param/shared/SharedParamsCodeGen.scala b/mllib/src/main/scala/org/apache/spark/ml/param/shared/SharedParamsCodeGen.scala
index c54062921fce..a267bbc87432 100644
--- a/mllib/src/main/scala/org/apache/spark/ml/param/shared/SharedParamsCodeGen.scala
+++ b/mllib/src/main/scala/org/apache/spark/ml/param/shared/SharedParamsCodeGen.scala
@@ -84,10 +84,10 @@ private[shared] object SharedParamsCodeGen {
       ParamDesc[String]("solver", "the solver algorithm for optimization", finalFields = false),
       ParamDesc[Int]("aggregationDepth", "suggested depth for treeAggregate (>= 2)", Some("2"),
         isValid = "ParamValidators.gtEq(2)", isExpertParam = true),
-      ParamDesc[Boolean]("collectSubModels", "If set to false, then only the single best " +
-        "sub-model will be available after fitting. If set to true, then all sub-models will be " +
-        "available. Warning: For large models, collecting all sub-models can cause OOMs on the " +
-        "Spark driver.",
+      ParamDesc[Boolean]("collectSubModels", "whether to collect a list of sub-models trained " +
+        "during tuning. If set to false, then only the single best sub-model will be available " +
+        "after fitting. If set to true, then all sub-models will be available. Warning: For " +
+        "large models, collecting all sub-models can cause OOMs on the Spark driver",
         Some("false"), isExpertParam = true)
     )
 
diff --git a/mllib/src/main/scala/org/apache/spark/ml/param/shared/sharedParams.scala b/mllib/src/main/scala/org/apache/spark/ml/param/shared/sharedParams.scala
index 34aa38ac751f..0004f085d10f 100644
--- a/mllib/src/main/scala/org/apache/spark/ml/param/shared/sharedParams.scala
+++ b/mllib/src/main/scala/org/apache/spark/ml/param/shared/sharedParams.scala
@@ -470,15 +470,17 @@ trait HasAggregationDepth extends Params {
 }
 
 /**
- * Trait for shared param collectSubModels (default: false).
+ * Trait for shared param collectSubModels (default: false). This trait may be changed or
+ * removed between minor versions.
  */
-private[ml] trait HasCollectSubModels extends Params {
+@DeveloperApi
+trait HasCollectSubModels extends Params {
 
   /**
-   * Param for whether to collect a list of sub-models trained during tuning.
+   * Param for whether to collect a list of sub-models trained during tuning. If set to false, then only the single best sub-model will be available after fitting. If set to true, then all sub-models will be available. Warning: For large models, collecting all sub-models can cause OOMs on the Spark driver.
    * @group expertParam
    */
-  final val collectSubModels: BooleanParam = new BooleanParam(this, "collectSubModels", "whether to collect a list of sub-models trained during tuning")
+  final val collectSubModels: BooleanParam = new BooleanParam(this, "collectSubModels", "whether to collect a list of sub-models trained during tuning. If set to false, then only the single best sub-model will be available after fitting. If set to true, then all sub-models will be available. Warning: For large models, collecting all sub-models can cause OOMs on the Spark driver")
 
   setDefault(collectSubModels, false)