diff --git a/app/rest/tree.go b/app/rest/tree.go
index fb954525..96e615c3 100644
--- a/app/rest/tree.go
+++ b/app/rest/tree.go
@@ -3,6 +3,7 @@ package rest
 import (
 	"sort"
 	"strings"
+	"time"
 
 	"github.com/umputun/remark/app/store"
 )
@@ -16,6 +17,12 @@ type Tree struct {
 type Node struct {
 	Comment store.Comment `json:"comment"`
 	Replies []*Node       `json:"replies,omitempty"`
+	ts      time.Time
+}
+
+// timeStamp wraps time.Time to simplify pointer ops
+type timeStamp struct {
+	time.Time
 }
 
 // MakeTree gets unsorted list of comments and produces Tree
@@ -27,10 +34,12 @@ func MakeTree(comments []store.Comment, sortType string) *Tree {
 	for _, rootComment := range topComments {
 		node := Node{Comment: rootComment}
 
-		commentsTree := res.proc(comments, &node, rootComment.ID)
+		ts := timeStamp{}
+		commentsTree, t := res.proc(comments, &node, &ts, rootComment.ID)
 		if rootComment.Deleted && len(commentsTree.Replies) == 0 { // skip deleted with no subcomments
 			continue
 		}
+		commentsTree.ts = t
 		res.Nodes = append(res.Nodes, commentsTree)
 	}
 
@@ -39,18 +48,26 @@ func MakeTree(comments []store.Comment, sortType string) *Tree {
 }
 
 // proc makes tree for one top-level comment recursively
-func (t *Tree) proc(comments []store.Comment, node *Node, parentID string) *Node {
+func (t *Tree) proc(comments []store.Comment, node *Node, ts *timeStamp, parentID string) (*Node, time.Time) {
+
+	if ts.IsZero() {
+		ts.Time = node.Comment.Timestamp
+	}
+
 	repComments := t.filter(comments, parentID)
 	for _, rc := range repComments {
+		if rc.Timestamp.After(ts.Time) {
+			ts.Time = rc.Timestamp
+		}
 		rnode := &Node{Comment: rc, Replies: []*Node{}}
 		node.Replies = append(node.Replies, rnode)
-		t.proc(comments, rnode, rc.ID)
+		t.proc(comments, rnode, ts, rc.ID)
 	}
 	// replies always sorted by time
 	sort.Slice(node.Replies, func(i, j int) bool {
 		return node.Replies[i].Comment.Timestamp.Before(node.Replies[j].Comment.Timestamp)
 	})
-	return node
+	return node, ts.Time
 }
 
 // filter returns comments for parentID
@@ -65,15 +82,16 @@ func (t *Tree) filter(comments []store.Comment, parentID string) (f []store.Comm
 }
 
 // sort list of nodes, i.e. top-level comments
+// time sort uses ts from latest reply
 func (t *Tree) sortNodes(sortType string) {
 
 	sort.Slice(t.Nodes, func(i, j int) bool {
 		switch sortType {
 		case "+time", "-time", "time":
 			if strings.HasPrefix(sortType, "-") {
-				return t.Nodes[i].Comment.Timestamp.After(t.Nodes[j].Comment.Timestamp)
+				return t.Nodes[i].ts.After(t.Nodes[j].ts)
 			}
-			return t.Nodes[i].Comment.Timestamp.Before(t.Nodes[j].Comment.Timestamp)
+			return t.Nodes[i].ts.Before(t.Nodes[j].ts)
 
 		case "+score", "-score", "score":
 			if strings.HasPrefix(sortType, "-") {
diff --git a/app/rest/tree_test.go b/app/rest/tree_test.go
index ac252b56..224c2af0 100644
--- a/app/rest/tree_test.go
+++ b/app/rest/tree_test.go
@@ -50,8 +50,8 @@ func TestTreeSortNodes(t *testing.T) {
 		{ID: "2", Timestamp: time.Date(2017, 12, 25, 19, 47, 2, 0, time.UTC), Score: 3},
 		{ID: "11", ParentID: "1", Timestamp: time.Date(2017, 12, 25, 19, 46, 11, 0, time.UTC)},
 		{ID: "13", ParentID: "1", Timestamp: time.Date(2017, 12, 25, 19, 46, 13, 0, time.UTC)},
-		{ID: "12", ParentID: "1", Timestamp: time.Date(2017, 12, 25, 19, 46, 12, 0, time.UTC)},
-		{ID: "131", ParentID: "13", Timestamp: time.Date(2017, 12, 25, 19, 46, 31, 0, time.UTC)},
+		{ID: "12", ParentID: "1", Timestamp: time.Date(2017, 12, 25, 19, 46, 14, 0, time.UTC)},
+		{ID: "131", ParentID: "13", Timestamp: time.Date(2017, 12, 25, 19, 50, 31, 0, time.UTC)},
 		{ID: "132", ParentID: "13", Timestamp: time.Date(2017, 12, 25, 19, 46, 32, 0, time.UTC)},
 		{ID: "21", ParentID: "2", Timestamp: time.Date(2017, 12, 25, 19, 47, 21, 0, time.UTC)},
 		{ID: "22", ParentID: "2", Timestamp: time.Date(2017, 12, 25, 19, 47, 22, 0, time.UTC)},
@@ -61,14 +61,13 @@ func TestTreeSortNodes(t *testing.T) {
 		{ID: "5", Deleted: true},
 	}
 
-	res := MakeTree(comments, "time")
-	assert.Equal(t, "1", res.Nodes[0].Comment.ID)
-
-	res = MakeTree(comments, "time")
-	assert.Equal(t, "1", res.Nodes[0].Comment.ID)
+	res := MakeTree(comments, "+time")
+	assert.Equal(t, "2", res.Nodes[0].Comment.ID)
+	t.Log(res.Nodes[0].Comment.ID, res.Nodes[0].ts)
 
 	res = MakeTree(comments, "-time")
-	assert.Equal(t, "6", res.Nodes[0].Comment.ID)
+	t.Log(res.Nodes[0].Comment.ID, res.Nodes[0].ts)
+	assert.Equal(t, "1", res.Nodes[0].Comment.ID)
 
 	res = MakeTree(comments, "score")
 	assert.Equal(t, "4", res.Nodes[0].Comment.ID)