Consider planting your poplar from seeds. If you decide to plant from seed, wait until October when the seeds are ripe. Dry them out for a few days on a plate or tray in your home. After they are dry, soak them overnight in lukewarm water.[3]
If you delay planting until spring, keep the seeds in the fridge over the winter in a plastic bag together with a lightly moistened mix of sand and peat.