A Detailed Guide to the Planting Techniques and Cultivation Management Methods of the Smoketree
The smoketree (Cotinus coggygria) is an important ornamental red-leaf tree species in China, also known as huanglumu, huanglutai, molinluo, and so on. It is a deciduous small tree or shrub of the genus Cotinus in the Anacardiaceae family. The famous red leaves of Fragrant Hills in Beijing come from this species. In landscaping, it is suitable for group planting on lawns, earthen mounds, or hillsides, and can also be mixed into other tree groups, especially evergreen tree groups. Now let us take a look at smoketree planting techniques!
Growth Habits of the Smoketree
The smoketree prefers light and also tolerates partial shade. It is cold-resistant, tolerant of drought, poor soil, and alkaline soil, but not tolerant of waterlogging. It is best planted in deep, fertile, sandy loam with good drainage. It grows quickly, has a well-developed root system, and has strong suckering ability. It has relatively strong resistance to sulfur dioxide. In autumn, when the temperature difference between day and night exceeds 10°C, the leaves turn red. It is native to southwestern China, northern China, and Zhejiang, and also grows in southern Europe, Syria, Iran, Pakistan, and northern India.
Smoketree Propagation Methods
1. Sowing: After the smoketree fruits mature in June to July, the seeds can be collected and stored in damp sand for 40 to 60 days before sowing. The seedlings have relatively poor cold resistance, so before winter arrives they need to be covered with leaves and straw for cold protection.
2. Division: The smoketree has very strong suckering ability. Before sprouting in spring, select well-grown root suckers on the outer side of the trunk, dig them up together with their fibrous roots, plant them in a nursery to grow, and then transplant them to their final location.
3. Cuttings: In spring, hardwood cuttings are used for the smoketree, and a plastic arch shed is needed to keep them warm and moist. During the growing season, under misting conditions, softwood cuttings with leaves are used, and they can root in about 30 days.
Smoketree Planting Techniques
1. Water management: After the smoketree seedlings emerge, sufficient watering is needed in the early stage of seedling growth, but within 20 days after the seedlings emerge, watering must be strictly controlled. As long as drought damage does not occur, watering should be reduced as much as possible, and the interval should depend on weather conditions, generally watering once every 10 to 15 days. In the later stage, watering should be properly controlled to help the seedlings harden off and facilitate overwintering. In autumn with more rainfall, attention should be paid to drainage to prevent water accumulation, which can cause root rot.
2. Thinning and final spacing: The smoketree should be appropriately densely planted. Thinning is generally carried out twice. The first thinning is done when the seedlings grow 2 to 3 true leaves. The second thinning is done when the leaves overlap each other, keeping the superior and removing the inferior, removing those that are poorly developed, affected by pests or diseases, mechanically damaged, or too dense, while maintaining a certain distance between seedlings, with a plant spacing of 10 cm being appropriate. In addition, replanting can be combined with the first or second thinning, preferably on cloudy days or in the evening.
3. Weeding and topdressing: Smoketree topdressing follows the principle of "small amounts and multiple applications, less first and more later." In the early stage of seedling growth, nitrogen fertilizer and phosphorus fertilizer are mainly used; during the rapid growth period of the seedlings, nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer should be mixed; during the hardening period of the seedlings, potassium fertilizer should be mainly used and nitrogen fertilizer should be stopped, so as to promote lignification of the seedlings and improve their cold resistance and overwintering ability. Weeding should follow the basic principle of "weed early, weed small, weed completely," removing weeds whenever they appear, and operations should be carried out carefully. Never bruise the seedlings, which could cause them to die.
Smoketree Pest and Disease Control
1. Aphids
[Damage] They harm leaves, tender stems, flower buds, and terminal buds, causing leaves to shrivel, curl, and form galls and then fall off. In severe cases, they cause the plant to wither and die.
[Control] When they occur in large numbers, spray 40% omethoate; from May to August, spray dimethoate, 50% malathion emulsion, or 40% acephate 1000 to 1500 times dilution once every 15 days; you can also spray derris extract 1000 to 2000 times dilution.
2. Damping-off
[Damage] It causes rot of the cortex of the roots or root collar, and in severe cases causes diseased seedlings to wilt and die.
[Control] Keep the garden clean and sanitary, promptly dispose of diseased plants, and spray 50% carbendazim 50% wettable powder 500 to 1000 times dilution, or spray 1:1:120 Bordeaux mixture once every 10 to 15 days.
3. Powdery mildew
[Damage] In the early stage, needle-head-sized white powdery spots appear on the leaves, gradually expanding into dirty-white round spots. The edges of the lesions are radial, and in the later stage the lesions merge into patches. In severe cases, the entire leaf is covered with a thick layer of white powder.
[Control] In the early stage of the disease, spray once with 20% triadimefon 800 to 1000 times dilution, and the effective period can reach 2 months. Or spray 70% thiophanate-methyl 1000 to 1500 times dilution several times.
4. Wilt disease
[Damage] Smoketree wilt disease is an important disease of the red leaves of Fragrant Hills. In mild cases, it seriously affects the red-leaf landscape; in severe cases, the plant quickly dies.
[Control] Dig out severely diseased plants and burn them to reduce sources of infection. Plant disease-resistant varieties. Treat the soil with a soil fumigant before planting the smoketree.