Growing a handkerchief tree ( Davidia involucrata) from seed is a long process requiring patience, as it can take many years for the tree to mature and flower. Here's a breakdown of the steps involved:
1. Seed Collection and Preparation:
- Collection: Collect seeds from ripe fruits in the fall.
- Pulp Removal: Clean the seeds thoroughly to remove any remaining pulp. The pulp contains inhibitors that prevent germination.
- Stratification (Cold Treatment): Handkerchief tree seeds require a period of cold stratification to break dormancy. This mimics the natural winter conditions that trigger germination.
- Method: Place the cleaned seeds in a container filled with moist (but not soaking wet) sand or vermiculite.
- Duration: Store the container in a refrigerator (around 35-40°F or 2-4°C) for several months (typically 3-6 months). Check the seeds periodically to ensure the medium remains moist.
2. Sowing the Seeds:
- Timing: Sow the seeds in the spring after the stratification period.
- Medium: Use a well-draining seed-starting mix.
- Sowing Depth: Plant the seeds about 1/2 inch (1.25 cm) deep.
- Watering: Water gently and keep the soil consistently moist, but not waterlogged.
3. Germination and Early Growth:
- Temperature: Maintain a temperature of 68-77°F (20-25°C) for optimal germination.
- Germination Time: Germination can take several weeks (approximately 3-4 weeks), so be patient.
- Light: Once the seedlings emerge, provide them with bright, indirect light.
- Transplanting: When the seedlings are large enough to handle (have a few sets of true leaves), transplant them into individual pots. Use a well-draining potting mix.
4. Growing the Seedlings:
- Watering: Water regularly, allowing the soil surface to dry slightly between waterings.
- Fertilizing: Feed the seedlings with a diluted balanced fertilizer every few weeks during the growing season.
- Protection: Protect the young plants from frost and harsh weather conditions. Consider growing them in a greenhouse or sheltered location for the first few years.
5. Planting Out:
- Timing: After the last late frosts in May (or when the risk of frost has passed in your area), and after the young tree is well-established (usually after a year or two), it can be planted in its permanent location in the open ground.
- Location: Choose a location with well-drained soil and partial shade. Handkerchief trees prefer slightly acidic soil.
- Planting: Dig a hole twice as wide as the root ball and as deep as the root ball. Gently remove the plant from its pot and place it in the hole. Backfill with soil and water thoroughly.
6. Patience is Key:
- Be prepared to wait a significant amount of time (up to 20 years or more) before your handkerchief tree produces its characteristic bracts (the "handkerchiefs").
Summary:
Growing a handkerchief tree from seed is a multi-step process that includes seed collection and cleaning, stratification, sowing, seedling care, and eventually, planting out. Success relies on providing the correct conditions and, most importantly, a great deal of patience.
