Zelkova serrata (Japanese elm) Propagation Seed Soak in warm water for 2 days Store 2-3 months at 5C Sow in Spring Links https://www.bonsaiempire.com/tree-species/zelkova http://www.bonsaitechniques.com/tree-species/zelkova-serrata/ https://www.bonsaitreegardener.net/bonsai-trees/species/zelkova https://www.maillot-bonsai.com/pdf/bulletin/bonsai_05_zelkova.pdf