Detailed Guide to the Latest Cultivation Methods for Potted Dan Gui Osmanthus

Dan Gui is a type of osmanthus tree, an evergreen tree of the genus Osmanthus in the family Oleaceae, native to southwestern China. Through long-term artificial cultivation, natural hybridization, and artificial selection, it has formed rich and diverse cultivated varieties. It is now widely cultivated in various regions and is commonly used as a landscaping tree species. Let us take a look together at the cultivation methods for potted Dan Gui!

Reasonable Watering

For potted Dan Gui, follow the principle of not watering when the soil is dry and watering thoroughly when you do. However, spray clear water on the leaf surface once a day, evenly moistening all branches and leaves, until water droplets begin to drip down. This keeps the leaves moist and washes away dust clinging to the leaves. After Qingming Festival, move the Dan Gui outdoors and water it thoroughly once. In summer, water in the morning and evening; in winter, water around noon so that the water temperature is close to the soil temperature and avoids sudden cold or heat. Be careful not to let water accumulate. In winter, keeping the potting soil moist is sufficient.

Timely Fertilizing

When Dan Gui sprouts new shoots, apply nitrogen fertilizer 1 to 2 times to promote branch and leaf growth. Before flower bud differentiation and flowering, mainly apply phosphorus fertilizer. In spring, after moving the Dan Gui outdoors, begin watering with diluted, fully decomposed soybean cake, sesame paste, or fish waste water, once every half month. From the end of May until before flowering, water once a week, gradually increasing the fertilizer concentration. From July to August, apply a 0.5% potassium dihydrogen phosphate solution as a top dressing once every half month. After flowering, apply a light fertilizer solution once to avoid triggering autumn shoots. In winter, apply more organic fertilizer and phosphorus-potassium fertilizer. Before fertilizing, the potting soil should be slightly dry, and it is best to loosen the soil first to aid fertilizer absorption. Water once the next day.

Choosing and Repotting Pots

For Dan Gui, flower pots made of purple clay ceramic or glazed ceramic are best. Purple or ochre colors are preferable, as they create a sharp contrast with the colors of the flowers and leaves and enhance the ornamental effect. Potted Dan Gui should be repotted and have its soil changed once every 2 to 3 years. Trim away some old roots and dead roots, and use a bamboo stick to remove some of the old soil. The soil ratio for potted Dan Gui is not very strict. Usually, garden soil, composted manure, and river sand can each make up 1/3 of the mix. After planting in spring, water thoroughly, then move it to a shaded place for about 10 days so it can “adjust to the pot.” Do not fertilize during this period. Only after it resumes growth and grows new leaves should you water and fertilize.

Shaping and Pruning

For Dan Gui shaping, curved-trunk, slanting-trunk, or flowing styles are best. Shaping generally uses a combination of bending and pruning. The main trunk can be bent into a curved-trunk or slanting-trunk form. This is best done in autumn. For plants that grow very tall with very sparse lower branches and a poor tree shape, cut off all the top branches at 2/3 or 3/4 of the height. For plants that are “top-heavy,” cut away the overly dense upper branches and leave only the smaller lower branches. For plants with overly dense branches, thin them out. After flowering, do another pruning, cutting away leggy branches, dead branches, diseased and pest-infested branches, and dense, weak, thin branches.

Overwintering Management

Room temperature should be kept at 0 to 5°C, and relative humidity should be kept at 50 to 80%. In winter, the cold room should have good light. Especially before buds begin to swell in early spring, even more sunlight is required. In spring of the following year, in North China, after Grain Rain (around Awakening of Insects in the Huang-Huai River basin), arrange for the potted Dan Gui to be moved outdoors. After moving out, first place them together in a wind-sheltered, sunny spot outdoors, and later spread them out in rows so they gradually adapt to the external environment.

Pest and Disease Control

Common diseases of Dan Gui include leaf spot disease, sooty mold, algal leaf spot, root rot, and iron deficiency. Control should be targeted to the disease condition. For leaf spot disease, sooty mold, and algal leaf spot, spray 0.5 Bordeaux mixture or 5% carbendazim 500 to 1000 times dilution for control. For root rot control, pay attention to keeping the soil loose and breathable and avoid water accumulation. If root rot is caused by fungi, use 200 to 300 times diluted amobam to irrigate the roots. Common pests of Dan Gui include sawflies, whiteflies, mites, long white scale insects, and yellow stinging caterpillars. Sawflies, whiteflies, and mites can be killed by spraying 40% dimethoate 1500 to 3000 times dilution. For long white scale insects, besides manual brushing, during the first and second instar nymph stages, spray 40% omethoate 1000 times dilution or 40% fenitrothion 500 times dilution to kill them.