Propagation Methods and Cultivation Techniques for the Large-Flowered Clivia

I. Propagation Methods: Clivia can be propagated by seed sowing and by vegetative propagation using the axillary buds, bulbs, and old roots of the vegetative body.

1. Seed propagation. Clivia is a cross-pollinated plant, so artificial pollination should be carried out to promote seed set. The seeds are basically mature only when the seed coat gradually turns from green to red or brownish-red. The external environment directly affects seed viability, especially temperature and humidity. If Clivia seeds are exposed to high temperatures of 45°C to 50°C for just over one hour, most of them will lose their germination capacity. The ideal storage temperature for seeds is below 20°C, and short-term storage is possible at temperatures not exceeding 30°C to 35°C. Clivia seeds germinate slowly; from sowing to the emergence of the coleoptile usually takes 40 to 45 days. Where conditions permit, appropriate treatment before sowing can promote rapid germination. The commonly used methods are: first, soaking the seeds in water at 40°C for 24 to 36 hours, which can advance the emergence of the radicle to about 20 days; second, soaking the seeds in a 10% sodium phosphate solution for 20 minutes, then removing and washing them and soaking them in water at the same temperature for 24 hours, after which they are sown in an incubator at a room temperature of 20°C to 25°C and a relative air humidity of 85%, where germination of the radicle can begin in as little as 6 days. The sowing medium can be sawdust, river sand, peat, etc., with a pH of 5.5 to 6.5 being best. Sowing time varies with region; it can be done as long as the temperature can be maintained at 20°C to 25°C (not exceeding 30°C). Based on China's climatic characteristics, sowing can be done in spring, autumn, and winter, among which spring sowing is the most common, with the period around Qingming being the best; in the south it can be done earlier, while in the north it should be later. Autumn sowing mainly makes use of early-ripening fruits, sowing them as soon as they are harvested, with the best time being between Chushu and Bailu. Winter sowing is mostly practiced in northern regions with heating equipment. After Clivia seeds germinate, roughly one and a half months later, when the true leaves emerge from the sheath, the first transplanting can be done, and when two true leaves have grown, they can be planted in their final position, one plant per pot.

2. Vegetative propagation. The most commonly used forms of vegetative propagation are division of offsets and division of bulbs. Division of offsets is the most widely used; axillary buds are drawn out from the axils of the mother plant's leaves, and their asexual reproductive capacity varies with the age of the plant and the cultivar. Generally, mature plants and common cultivars readily produce axillary buds. The timing of division varies with local conditions: where there is heating equipment or a medium-temperature greenhouse, it can be done all year round; in the Yangtze River basin and areas to its south, it is best done before Guyu, and division can also be done in autumn, generally between Bailu and Qiufen. When the offsets have grown to 6-7 leaves, remove the offsets around the mother plant when repotting in spring. After division, the wounds on both the mother plant and the offsets should be coated with fine stove ash to prevent sap from flowing from the wounds, to dry the wounds quickly, and to prevent rot. If the offsets have few roots, they can be planted in fine sand, keeping the room temperature at 20-25°C, which is favorable for root initiation and growth. Larger offsets will bloom after 1-2 years of care. As for the timing of bulb division propagation, regardless of the region, it can be carried out as long as the temperature can be kept stable at around 20°C.

II. Cultivation Techniques: Clivia prefers a warm, cool environment, is not cold-tolerant, and dislikes high heat; its optimum growing temperature is 20°C to 25°C. When the temperature is below 10°C, the plant grows slowly, and when it exceeds 30°C, the leaves and flower stalks will become leggy; a temperature difference of 10°C is most favorable for the growth and development of Clivia. When the winter room temperature is below 5°C, growth will be inhibited. It fears direct sunlight and prefers semi-shade. During high summer temperatures, Clivia enters a semi-dormant state.

It has strict soil requirements, and aeration and drainage are key; otherwise the fleshy fibrous roots rot easily. A loose soil rich in humus is best, with peat being especially ideal, and saline-alkaline soil should be avoided. During cultivation, attention must be paid to water control; the soil should be neither dry nor wet, and the air humidity should be 70%-80%. If the soil is too wet or the relative humidity is too high, Clivia is prone to disease. In dry seasons, water should be sprayed frequently to prevent the air from becoming too dry, which causes the leaf margins to wither. Watering should be moderate; waterlogging easily causes root rot and death.

Light is closely related to the growth and development of Clivia. Clivia is a medium-light plant; it fears direct sunlight and prefers semi-shade, and does not need strong light during growth, especially in summer, when direct sunlight must be avoided. Strong light shortens the flowering period and affects ornamental value, while weak light can prolong the flowering period. Shortening the light period in winter can make the flowering period come earlier.

During cultivation, in addition to strictly controlling water, light, and temperature, fertilization must be scientific. Clivia is a fertilizer-loving plant, so sufficient base fertilizer should be applied when repotting, and a nitrogen fertilizer should be applied every 20 days as a top dressing, commonly using decomposed cake fertilizer water. When applying top dressing, care should be taken not to touch the leaves, so as to avoid damage. Before Clivia blooms, apply an additional dressing of bone meal or superphosphate, which can make the flower colors more vivid and the flowers larger. With proper cultivation and management, Clivia blooms once a year, or even twice. After the flowers fade between April and May, repotting is needed; gently remove the stale leaf mold, taking care not to break the fleshy roots, choose a pot of suitable size, and plant it promptly, placing more broken tiles at the bottom of the pot to facilitate drainage.

In winter, Clivia often shows the "stuck arrow" phenomenon, in which the small flowers open before the flower stalk has grown out of the false bulb. The main reason is that when the flower stalk appears, it is affected by low temperature and low soil moisture content. As long as the temperature is appropriately raised and the amount of watering increased during the period when the flower stalk is emerging, the occurrence of the "stuck arrow" phenomenon can be prevented.

III. Common diseases of Clivia include:

1. Soft rot. It generally occurs in the lower leaf sheath area. At first, the lesion looks as if a few drops of oil have been dripped on the leaf, is pale yellow in color, appears as a water-soaked lesion, and is translucent. The lesion then spreads outward, often joining together into an irregular shape, gradually becoming brown and soft-rotted, and finally rotting. This disease is caused by infection with Erwinia, and its predisposing factors include: excessively high temperature, excessively high humidity, poor ventilation, insufficient light, and dust collecting in the leaf sheath area. Control methods: prevention should be the priority. After the disease occurs, spraying with a 0.5% Bordeaux mixture can be used, or medical penicillin, streptomycin, oxytetracycline, and similar drugs can be diluted to a 5000-fold solution and sprayed, or applied to the lesions; all have a certain therapeutic effect.