Detailed Guide to Sourcing Methods and Cultivation Techniques for Ash Bonsai

  Ash trees belong to the genus Fraxinus in the family Oleaceae. They are deciduous trees widely planted in China. They prefer sunlight and tolerate slight shade. They can be propagated by sowing seeds, as well as by cuttings, division and layering. Ash trees have strong sprouting ability, a high survival rate and fast growth, making them excellent material for making bonsai with grafted osmanthus. You can use discarded ash stumps, or buy ash stumps suitable for bonsai from a nursery, cultivate and shape them, and then graft osmanthus onto them.

  The selection of ash stump material is the same as that for other bonsai stumps: choose stumps with good form and vigorous growth that are suitable for bonsai. After digging up the stump, cut off the large roots, keep the fibrous roots, retain the branches and trunk needed according to bonsai shaping requirements, and remove the excess branches and trunk. Depending on the condition of the stump, plant it in the ground for 1 to 2 years before potting and grafting. If the stump has a good root system and the branches and trunk are of suitable thickness and length, it can be potted and grafted in the same year it is dug up. Digging and potting should be done in early winter after leaf fall and in spring before the sap begins to flow in ash and osmanthus trees.

  Chinese ash (Fraxinus chinensis) stumps purchased from far from their place of origin are all dug up by mountain villagers in winter and early spring. In places where they are locally cultivated, they can be dug at any time except from mid-June to mid-August. Mountain villagers generally provide poor protection during digging and transport. Although this tree species has very strong vitality, in order to achieve a higher survival rate, attention must still be paid to the varying degrees of dehydration they suffer.

  First, pruning should be done in one go. This tree species roots easily; even a saw cut on a root 200mm in diameter can still produce fibrous roots, so any roots or branches that would hinder future potting or shaping should be decisively sawn off.

  Second, they must absorb enough water. If conditions permit, it is best to place the roots upright and soak them in water dissolved with a rooting agent (such as rooting powder or vitamin B12). The treatment time should follow the rooting agent's instructions. Alternatively, soak the entire stump in clean water for a full day and night, then plant it in a sand bed for care. The burial depth of the roots should be above 20cm; for old stumps with a trunk diameter greater than 20cm and split-trunk stumps, it should be increased appropriately. Spacing between stumps: for medium-sized stumps, the spacing should be greater than 0.5m; for large stumps, it should be greater than 1m. This is beneficial for branch extension; otherwise the branches shade each other, which is not conducive to growth or to operations during pruning and shaping.

  Third, after planting, water thoroughly so that the sand comes into close contact with the gaps around the roots. Keep the sand bed moist at ordinary times and sprinkle water on the trunk frequently. If protected with 30%-50% shade netting, the effect will be even better. Under normal circumstances, they will sprout by late spring and early summer. After the Beginning of Autumn in early August, the shade netting can be removed to let them enjoy full sunlight. From late April to early May, if there are still stumps that have not sprouted, scrape their bark with a small knife; if the bark at the top is still emerald green rather than withered yellow, they can be pulled out of the sand bed, soaked in clean water for a full day and night, then planted in sand in a half-shade, half-sun location for care, which can still promote sprouting and survival.