White Orchid Tree Propagation Methods and Daily Care Key Points

Propagation Methods The white orchid tree (Michelia alba) is mainly propagated by grafting and layering; sowing and cuttings are rarely used.

Grafting propagation is mainly done by cut grafting and approach grafting. For approach grafting, in February to March select a purple magnolia (Magnolia liliiflora) with a trunk diameter of 0.6 cm as the rootstock and pot it; then approach graft from April to September, with May to June being the best. Select a healthy white orchid tree branch of the same thickness as the rootstock as the scion, shave off the bark and part of the xylem of both the rootstock and the scion to a length of 6 cm (the cut surfaces must be smooth), then align the cambium layers of the two cut surfaces and press them tightly together, and tie them firmly with plastic tape. About 50 days after grafting, once the graft union has healed, it can be cut away from the mother plant. The new plant should first be placed in a shaded spot, and the cover uncovered in the evening; take care to protect it from wind so that it does not break at the graft. For cut grafting, use a sturdy 1-2 year old purple magnolia as the rootstock, and carry it out on a sunny day in mid-March. After about 20-30 days, the terminal bud sends out leaves. From early June begin applying dilute fertilizer, and stop fertilizing in late August. In October to November it can be dug up and potted, then moved into a greenhouse for cultivation. Generally, a seedling of the current year can reach 60-80 cm tall, 3-4 times faster than approach grafting.

Air layering. From late June to early August, select a sturdy, well-growing two-year-old branch and perform girdling 55 cm from the tip, with the girdled ring 2.5 cm wide. Immediately after girdling, dip absorbent cotton in B12 injection and lightly apply it to the cut, then enclose the girdled spot with a split bamboo tube, flower pot or clay bowl, bind it firmly with rope, and prop it up with a T-shaped wooden frame so that the bamboo tube or flower pot is fixed in place. Alternatively, score the bark with a knife, then wrap the wound with nutrient soil and moss, cover and tie it tightly with plastic film on the outside, and keep the rooting area moist frequently; first place broken tile pieces 1 to 1.5 cm in diameter inside, about 2 cm thick, then fill in potting soil, firm it and water it. After air layering, take care to water the pot of the layered branch frequently so that the soil in the pot stays moist but slightly dry. About 1 month after layering, on the same branch 5 to 7 cm below the girdling cut, use a sharp knife to cut away a small piece of bark, with the vertical cut depth being one-seventh of the branch's cross-section. At the same time, apply an appropriate amount of 500-fold potassium dihydrogen phosphate aqueous solution to the pot. After that, about every 10 days cut once at the same spot in a different direction, so as to gradually reduce the layered branch's nutrient and water connection with the mother plant and force the layered branch to absorb more water and nutrients from the soil in the pot. After cutting 3 to 4 times in this way, the girdled spot will heal and form a nodule, and root buds will appear. To make the layered branch send out more and longer new roots, the branch can be cut 6 to 8 times in succession. The cutting must be carried out gradually; do not be impatient. Observe carefully the leaf color and growth vigor of the layered branch; if yellowing and wilting appear, slow the cutting rate or pause cutting. Under normal conditions, 3 to 4 months after cut layering, the layered branch already has quite a few new roots, so it can be cut off and planted, then cared for in shade for about half a month before transitioning to normal management.

Cultivation and Management Generally, the plants are moved outdoors after Qingming and before Guyu. Before moving them outdoors, the pots must be changed; when moving them outdoors, water thoroughly once, and thereafter water every other day. Generally, small seedlings are repotted every 1-2 years and large seedlings every 3-4 years, from late April to early May, adding loose, fertile soil, which is beneficial for root development. Watering is also key to cultivating white orchid trees well. After moving outdoors in spring, watering at noon is best, once every other day, but each watering must be thorough. In summer, water once each morning and evening, and in midsummer appropriately increase the frequency of misting. In autumn, water thoroughly once every 2-3 days; in winter, control watering and just keep the potting soil moist. For plants after flower harvesting and weak-growing plants, reduce watering to avoid excessive growth of branches and leaves or to avoid affecting growth. At the same time, the water temperature should not be too cold and should not differ much from the potting soil. The white orchid tree has dense branches and leaves and a long flowering period; apply decomposed cake fertilizer water once every 10 days, and before flowering also supplement phosphorus and potassium fertilizer to help new leaves emerge and promote flowering. Generally, pick leaves once each at the start of spring, the start of autumn, and before the onset of winter every year. In winter, keep the indoor minimum temperature above 5°C. In summer, pay attention to the placement; poor ventilation makes it prone to pests and diseases. During the growing period, prune diseased branches and dead branches. Also prune excessive-growth branches and remove some old leaves to suppress the tree's vigor and promote flower bud formation. From June to July it enters full bloom, and the flowers picked in the morning have the strongest fragrance.