Madrone Seed Germination at WSU-Puyallup

a man in a greenhouse holding a tray filled with conical yellow tubes. on the table in front of him are more yellow tubes. The rest of the table is covered in segmented trays with young madrone plants.

Fruit should be red and fully ripe when collected, usually in October but varies by region.

Processing fruit:

  1. Soak fruit for at least 24 hrs.
  2. Macerate fruit in the blender for 2- 5 minutes, depending on how firm it is.
  3. After maceration, float off the unripe seed and outer parts of the berry.
  4. Dry seed at room temp for one week.
  5. Store in glass jars at 34 ۫ F.

Propagation:

  • Soak seed for 24 hrs.
  • Surface sterilized for 10 min. with 10% bleach solution.
  • Moist stratify at 34F for 60 days.
  • Sow in plug trays and top-dress lightly with fine vermiculite.
  • Germinate at 68-80 ۫ F.
  • Drench with a fungicide to prevent damping-off (optional).
  • Fertigate weekly at 100 ppm N to start, building up to 300 ppm N at the end of plug stage.
  • After two months (approx.), transplant plugs into 0.5ℓ treepots for one season, after which they are outplanted to the field.

WSU Puyallup Research & Extension Center
2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated 9/24/2025