--- a/mozilla-tests/config.py
+++ b/mozilla-tests/config.py
@@ -57,17 +57,17 @@ BRANCHES = {
         },
         'lock_platforms': True,
     },
     'try': {
         'coallesce_jobs': False,
     },
 }
 
-TWIGS = [x for x in ACTIVE_PROJECT_BRANCHES if x not in ('mozilla-inbound', 'fx-team')]
+TWIGS = [x for x in ACTIVE_PROJECT_BRANCHES if x not in ('mozilla-inbound', 'fx-team', 'larch')]
 
 setMainFirefoxVersions(BRANCHES)
 
 # Talos
 PLATFORMS = {
     'linux': {},
     'linux64': {},
     'linux64-asan': {},

--- a/mozilla/project_branches.py
+++ b/mozilla/project_branches.py
@@ -314,19 +314,25 @@ PROJECT_BRANCHES = {
         'stage_product': {
             'firefox': 'firefox',
             'fennec': 'mobile',
         },
         'push_to_releases_automatic': False,
         'merge_builds': False,
     },
     'larch': {
-        'lock_platforms': True,
-        'platforms': {
+        'merge_builds': False,
+        'repo_path': 'projects/larch',
+        'enable_perproduct_builds': True,
+        'mozconfig_dir': 'mozilla-central',
+        'pgo_strategy': 'periodic',
+        'talos_suites': {
+            'xperf': 1,
         },
+        'branch_projects': ['spidermonkey_tier_1', 'spidermonkey_info'],
     },
     # disabled in bug 1215527
     # 'maple': {},
     # customizations for integration work for bugs 481815 and 307181
     'oak': {
         'enable_nightly': True,
         'updates_enabled': True,
         'create_partial': True,