Mountain Maple

Acer spicatum

Sapindaceae, Aceraceae · broadleaf deciduous tree · native

Last updated March 8, 2026

Data Coverage 3 of 6 dimensions

Site Data

Threats

Cultivars

Phenology

GDD Thresholds

Puget Sound

Quick Facts

Height

15 ft

Growth Rate

Moderate

Light

Part Shade

Soil

Wet Tolerant

Water

Moderate

Hardiness

Zone Zones 2a–8b

Bloom Time

Mar 15-May 15

Fall Color

Brown, orange, scarlet, yellow

Origin

eastern North America, from Labrador east to Saskatchewan

Phenological Calendar

Stage	Typical Window	What to Look For
Bud break BBCH 07	Feb 15-Mar 15	Buds swelling and beginning to open; first green tissue visible
Leaf emergence BBCH 11	Mar 1-Apr 1	First leaves fully unfurled on new growth
Bloom start BBCH 61	Mar 15-May 15	First open flowers visible; flowers yellow
Bloom end / petal fall BBCH 69	Apr 15-May 31	Last petals falling; flower structures fading
Fruit/seed development BBCH 71	Jun 1-Aug 31	Fruit or seed structures forming; fruit color: brown
Fruit/seed maturity BBCH 85	Sep 1-Nov 30	Fruit fully colored and ripened; seed dispersal may begin
Fall color / leaf senescence BBCH 93	Oct 1-Nov 15	Leaves changing color; fall display beginning
Dormancy BBCH 97	Nov 15-Feb 28	Leafless; no active growth; dormant buds set

Diseases (19)

Verticillium dahliae Verticillium Wilt Rhytisma punctatum Tar Spots Podosphaera aphanis var. aphanis Powdery Mildew Phyllosticta spp. Phyllosticta Leaf Spot Neonectria ditissima Nectria Canker abiotic (drought, heat stress) or bacterial (Xylella fast... Leaf Scorch Multiple possible causes (see Disease Cycle section) Fasciation Pseudomonas syringae Bacterial Leaf Spot and Dieback Colletotrichum acutatum complex (C Anthracnose Kretzschmaria deusta Brittle Decay Limb and Wood Decay Armillaria ostoyae Armillaria Root Rot Bigleaf Maple Decline (Bigleaf Maple Dieback) Phytophthora spp. (P Bleeding Canker Various fungi (Phoma spp., Phomopsis spp., Cytospora spp.... Branch Canker Taphrina spp. Leaf Blister Symptom category — not a single disease Leaf Spot Phytophthora spp. (P Phytophthora Root Rot Cryptostroma corticale Sooty Bark Disease

Pests (13)

Vasates quadripedes Maple Bladdergall Mite Pulvinaria innumerabilis Cottony maple scale Aphidoidea Aphid Boisea rubrolineata Western boxelder bug Prionoxystus robiniae Carpenterworm Megachile spp. Leafcutting bee Proteoteras aesculana Maple tip moth (Maple twig borer) Lepidosaphes ulmi Oystershell scale Otiorhynchus spp. Root weevil Edwardsiana rosae Rose leafhopper Leucoma salicis Satin moth Frankliniella occidentalis Western flower thrips Proteoteras moffatiana Maple shoot moth