Albizia julibrissin 'Rosea' (Pink Silk Tree)

Description of the Tree

Albizia julibrissin 'Rosea', commonly known as the Pink Silk Tree or Mimosa Tree, is a deciduous ornamental species native to southwestern and eastern Asia. This cultivar features a distinctive broad, umbrella-shaped canopy with delicate, feathery compound leaves that demonstrate nyctinastic movement, folding in the evening or when touched. The tree is primarily valued for its spectacular summer display of silky, pink, pom-pom-like flower clusters that emerge from June through August. Reaching heights of 6-12 meters (20-40 feet) at maturity with a similar spread, Albizia julibrissin 'Rosea' provides an elegant, tropical appearance in temperate landscapes. The tree produces flat, bean-like seed pods that mature to a light brown color in autumn.

Albizia julibrissin 'Rosea' Seed Growth Guide

Seeds of Albizia julibrissin 'Rosea' feature a hard seed coat that requires specific pre-treatment to achieve successful germination. With proper scarification techniques and optimal growing conditions, these seeds offer a cost-effective method of propagation. The guide below outlines essential considerations for cultivating this ornamental tree from seed, with emphasis on breaking seed dormancy to ensure viable seedling development.

Germination Profile

Germination Rating: 3.5/5.0 (moderate difficulty due to seed coat dormancy) Germination Time: 2-4 weeks after scarification Germination Temperature: Optimal between 20-25°C (68-77°F) Viability: Seeds maintain good viability for 2-3 years when properly stored Germination Medium: Well-draining, fertile soil mix Success Rate: High with proper scarification techniques; low without pre-treatment

Planting Instructions

1. Collect or purchase mature seeds from established pods, selecting those that appear full and undamaged.
2. Scarify seeds by either:
   • Nicking the seed coat with a small file or sandpaper
   • Soaking in concentrated sulfuric acid for 20-30 minutes (professional method)
   • Pouring boiling water over seeds and allowing them to soak for 24 hours as water cools
3. After scarification, plant seeds at a depth of approximately 1 cm (0.4 inches) in a well-draining growing medium.
4. Maintain soil moisture at consistently damp but not saturated levels.
5. Provide bottom heat of 20-25°C (68-77°F) if possible to enhance germination rates.
6. Germination typically occurs within 2-4 weeks when properly scarified.
7. Monitor regularly and maintain adequate ventilation to prevent fungal issues.

Care After Germination

Growth Speed: 4.5/5.0 (relatively fast) Light Requirements: Full sun to partial shade; minimum 6 hours direct sunlight daily for optimal growth Watering Needs: Regular watering during establishment; drought tolerant once established Soil Preferences: Adapts to various soil types but prefers well-draining, slightly acidic to neutral soils Fertilization: Apply balanced, slow-release fertilizer in spring after first year Transplanting: Transplant to individual containers when seedlings reach 10-15 cm; final planting after risk of frost has passed Protection: Provide wind protection for young specimens; may require winter protection in colder zones Plant Care Rating: 4.0/5.0 (relatively easy maintenance requirements)

Summary

Albizia julibrissin 'Rosea' represents an excellent choice for landscape designers and gardeners seeking a distinctive ornamental tree with striking summer flowers and attractive foliage. While seed germination requires specific pre-treatment to overcome coat dormancy, this initial challenge is offset by the relatively fast growth rate and adaptable nature of established seedlings. With a germination difficulty of 3.5/5.0 primarily due to seed coat dormancy rather than inherent viability issues, successful propagation is achievable with proper techniques. The tree's drought tolerance once established (4.0/5.0 care rating) and impressive growth rate (4.5/5.0) make it a rewarding species to cultivate from seed. Given its exceptional ornamental qualities featuring delicate, compound foliage and spectacular pink, silky flowerheads, Albizia julibrissin 'Rosea' serves as a dramatic focal point in appropriate landscapes, providing tropical aesthetics, dappled shade, and valuable habitat for pollinators.