Apple
Malus domestica
Rosaceae · broadleaf deciduous tree · introduced
Last updated
Apples in the Puget Sound lowlands demand more management than most home gardeners expect. Scab thrives in wet springs and is the primary fungal threat; codling moth and apple maggot are the two key insect pests. Codling moth attacks early (May-June first generation, July-August second generation) and bores to the core. Apple maggot is single-generation, peaking July-August with meandering flesh tunneling. Without some form of spray program or physical barriers (bagging, trunk banding), expect damaged fruit most years. Cultivar choice is the first defense: modern disease-resistant varieties (Liberty, Enterprise, Pristine) significantly reduce scab pressure and spray needs. Dwarf rootstocks (M.9, M.26) keep trees manageable for spraying, pruning, and netting. Site in full sun with good air circulation to minimize powdery mildew and reduce overwintering pest populations. Most varieties need a pollinizer; check bloom-time compatibility. Late-maturing cultivars (Fuji, Granny Smith) avoid some early pest pressure. Most lowland soils are adequate if drainage is acceptable; on alluvial clay or over shallow hardpan, raised beds improve results. Summer drought stress opens the door to secondary pests and disease. If you are not willing to spray at all, consider heirloom or cider varieties that tolerate cosmetic damage, or choose dwarf, bagged trees for spotless fruit.
— Chris Welch, ISA Certified Arborist
Malus domestica (Rosaceae) is a deciduous fruit tree originating in Central Asia (primarily Kazakhstan and adjacent regions). It grows 15 to 30 feet tall and wide depending on rootstock, forming a rounded to spreading crown. Pink-white flowers (1 to 1.5 inches across) appear in cymes of 4 to 6, with the central "king bloom" opening first. Thousands of cultivars exist, spanning a vast range of fruit size, color, flavor, and ripening season.
Apple requires full sun to part shade on moist, well-drained soil (pH 6.0 to 8.0). Most cultivars are not self-fertile and require a compatible pollination partner blooming at the same time. Maintenance is high: the species is subject to extensive disease pressure (scab, fire blight, powdery mildew, cedar-apple rust among others) and insect damage (codling moth, apple maggot, aphids). Dwarfing rootstocks control tree size and often improve precocity. Hardy in Zones 4a to 9b.
Quick Facts
Phenological Calendar
As of April 20, 2026, Puget Sound stations range from 1373.1 to 1531.6 GDD₃₂. Apple has reached fruit set / young fruit development (1160 GDD₃₂) and is approaching peak first-generation codling moth entry, predicted around May 4.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 20, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,532 | Fruit set / Young fruit development | Peak first-generation codling moth entry | 268 |
| Seattle / UW | 1,493 | Fruit set / Young fruit development | Peak first-generation codling moth entry | 307 |
| Kent / Auburn | 1,472 | Fruit set / Young fruit development | Peak first-generation codling moth entry | 328 |
| Olympia / Tumwater | 1,444 | Fruit set / Young fruit development | Peak first-generation codling moth entry | 356 |
| Bellingham / Whatcom | 1,417 | Fruit set / Young fruit development | Peak first-generation codling moth entry | 383 |
| Tacoma / Puyallup | 1,411 | Fruit set / Young fruit development | Peak first-generation codling moth entry | 389 |
| Sequim / Rain Shadow | 1,373 | Fruit set / Young fruit development | Peak first-generation codling moth entry | 427 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| Dormancy break / Bud swell BBCH 01 | — | Late February to mid-March (Kent, WA) |
| Green tip BBCH 03 | 375 | Mid-March (Kent, WA) |
| Tight cluster BBCH 05 | 548 | Late March to early April (Kent, WA) |
| Pink bud BBCH 57 | 730 | Mid-April (Kent, WA) |
| Full bloom BBCH 65 | 754 | Mid-April (Kent, WA) |
| Petal fall BBCH 67-69 | 841 | Late April (Kent, WA) |
| ● Fruit set / Young fruit development BBCH 71-75 NOW | 1160 | Mid to late May (Kent, WA) |
| Fruit bagging window BBCH 75-79 | 1125 | Late May through early June (Kent, WA) |
| ○ Peak first-generation codling moth entry BBCH 79-81 NEXT | 1800 | June through early July (Kent, WA) est. May 4 (forecast) |
| Fruit diameter increase / Late development BBCH 81-87 | 2280 | Late June through July (Kent, WA) est. May 25 (avg) |
| Maturity / Pre-harvest BBCH 87-89 | 3400 | August through October depending on cultivar (Kent, WA) est. Jul 4 (avg) |
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Hover over GDD values for source details. Season tracker for Kent / Auburn as of Apr 20, 2026. Predicted dates use 16-day weather forecast through May 6, 2026, then climate normals.