Ailanthus trees flower in February-March and the fruit, a reddish brown samara, ripens in March-April, which represents the ideal time for seed collection. The seeds can be stored only for a few months. Alternate wetting and drying improves seed germination. The procedure involves soaking the entire quantity of seeds in cold (room temperature) water in the evening and draining the water next morning, followed by drying the seeds under shade during the day. The cycle is repeated for two to three days.