diff --git a/environment.cpp b/environment.cpp
index 59802837..51f3d1c4 100644
--- a/environment.cpp
+++ b/environment.cpp
@@ -240,6 +240,7 @@ EX void computePathdist(eMonster param, bool include_allies IS(true)) {
       cell *c2 = cw1.peek();
       
       flagtype f = P_MONSTER;
+      if(param == moIvyRoot) f |= P_IVY;
       if(param == moTameBomberbird) f |= P_FLYING | P_ISFRIEND;
       if(isPrincess(param)) f |= P_ISFRIEND | P_USEBOAT | P_CHAIN;
       if(param == moGolem) f |= P_ISFRIEND;
@@ -251,7 +252,7 @@ EX void computePathdist(eMonster param, bool include_allies IS(true)) {
         
         if(qb >= qtarg) {
           if(param == moTortoise && nogoSlow(c, c2)) continue;
-          if(param == moIvyRoot  && strictlyAgainstGravity(c, c2, false, MF_IVY)) continue;
+          if(param == moIvyRoot  && !ivy_passable(c, c2)) continue;
           if(param == moWorm && (cellUnstable(c) || cellEdgeUnstable(c) || prairie::no_worms(c))) continue;
           if(!isFriendly(param) && items[itOrbLava] && c2->cpdist <= 5 && pseudohept(c) && makeflame(c2, 1, true))
             continue;
diff --git a/flags.cpp b/flags.cpp
index 87f8b60c..d5792362 100644
--- a/flags.cpp
+++ b/flags.cpp
@@ -214,7 +214,7 @@ EX bool isFlying(eMonster m) {
   }
 
 EX bool survivesChasm(eMonster m) {
-  return isFlying(m);
+  return isFlying(m) || isAnyIvy(m);
   }
 
 EX bool ignoresPlates(eMonster m) {
diff --git a/monstermove.cpp b/monstermove.cpp
index 38813aaa..c45994b3 100644
--- a/monstermove.cpp
+++ b/monstermove.cpp
@@ -1041,7 +1041,7 @@ EX void moveivy() {
             }
           continue;
           }
-        if(c2 && c2->pathdist < pd && passable(c2, c, 0) && !strictlyAgainstGravity(c2, c, false, MF_IVY))
+        if(c2 && c2->pathdist < pd && ivy_passable(c2, c))
           mi = movei(c, j), pd = c2->pathdist;
         }
       c = c->move(c->mondir);
@@ -1437,7 +1437,7 @@ EX void movemutant() {
       
       if(isPlayerOn(c2)) continue;
 
-      if((c2->land == laOvergrown || !pseudohept(c2)) && passable(c2, c, 0)) {
+      if((c2->land == laOvergrown || !pseudohept(c2)) && ivy_passable(c2, c)) {
         if(c2->land == laClearing && !closed_or_bounded && c2->mpdist > 7) continue;
         c2->monst = moMutant;
         c2->mondir = c->c.spin(j);
diff --git a/orbs.cpp b/orbs.cpp
index b28800a6..eb95dd27 100644
--- a/orbs.cpp
+++ b/orbs.cpp
@@ -1482,7 +1482,7 @@ EX eItem targetRangedOrb(cell *c, orbAction a) {
         if(c->monst ? (
           CHK(canAttack(cf, moFriendlyIvy, c, c->monst, f), XLAT("Cannot attack there!"))
           ) : (
-          CHK(passable(c, cf, P_ISFRIEND | P_MONSTER), XLAT("Cannot grow there!")) &&
+          CHK(passable(c, cf, P_ISFRIEND | P_MONSTER | P_IVY), XLAT("Cannot grow there!")) &&
           CHK(!strictlyAgainstGravity(c, cf, false, MF_IVY), XLAT("Cannot grow against gravity!"))
           ))
           dirs.push_back(d);
diff --git a/passable.cpp b/passable.cpp
index 662d4ea5..a34435a7 100644
--- a/passable.cpp
+++ b/passable.cpp
@@ -138,6 +138,7 @@ EX bool anti_alchemy(cell *w, cell *from) {
 #define P_PHASE      Flag(33) // phasing movement
 #define P_PULLMAGNET Flag(34) // pull the other part of the magnet
 #define P_WATERCURSE Flag(35) // Curse of Water
+#define P_IVY        Flag(36) // ivy
 #endif
 
 EX bool passable(cell *w, cell *from, flagtype flags) {
@@ -270,7 +271,7 @@ EX bool passable(cell *w, cell *from, flagtype flags) {
     }
   if(isChasmy(w)) {
     if(in_gravity_zone(w)) ;
-    else if(!F(P_AETHER | P_FLYING | P_BLOW | P_JUMP1 | P_BULLET | P_DEADLY | P_REPTILE)) return false;  
+    else if(!F(P_AETHER | P_FLYING | P_BLOW | P_JUMP1 | P_BULLET | P_DEADLY | P_REPTILE | P_IVY)) return false;
     }
 
   if(w->wall == waRoundTable && from && from->wall != waRoundTable && (flags & P_ISPLAYER)) return true;
@@ -467,6 +468,14 @@ EX bool isNeighbor1(cell *f, cell *w) {
   return !f || f == w || isNeighbor(f, w);
   }
 
+EX bool ivy_passable(cell *c2, cell *c) {
+  if(!passable(c2, c, P_IVY)) return false;
+  if(isWatery(c2)) return false;
+  if(strictlyAgainstGravity(c2, c, false, MF_IVY)) return false;
+  if(cellUnstableOrChasm(c) && cellUnstableOrChasm(c2)) return false;
+  return true;
+  }
+
 EX bool passable_for(eMonster m, cell *w, cell *from, flagtype extra) {
   jumpdata jdummy;
   if(w->monst && !(extra & P_MONSTER) && !isPlayerOn(w))