Written by Maggie
Jan 15 2021
Mexican sunflowers, scientific name Tithonia diversifolia, is a genus for the stout herbs. Leaves are often alternate, 3-veined; Inflorescences are opposite, radiate, yellow, sunflower like, on a long stalk; Involucral bracts are 2-5 columns; Inflorescence is receptacle with rigid receptacle; Ligulate flowers are beautiful, neutral; Disk flowers ar bisexual, fruiting; Achene is slightly compressed or quadrilateral, apex with burbs or scales. Among the 10 species of Mexican Sunflowers distributed in America.
Mexican sunflowers are annual plants, 2 to 5 meters tall. Stem is erect, with stout branches, densely pubescent or usually depleted below.
Leaves are ovate or ovate-triangular or suborbicular, 7-20 cm long, 3-5 deeply lobed, with long petioles, upper leaves sometimes undivided, lobes ovate or lanceolate, margin serrate, underside spiked pubescent, hairs thicker along veins, base triveined.
Mexican sunflowers are large heads, 5 -- 15 cm wide, terminating on a long peduncle branching on a pseudaxis. Involucral bracts are 4-ply, outer elliptic or elliptic-lanceolate, base leathery; Inner bracts are long lanceolate, distally foliaceous or membranous, apically obtuse. The ligate Flower is 1 layer, yellow, the liguate piece is long ovate, the apex has not obvious 3 teeth; The tubular flowers are yellow.
Achenes of Mexican sunflowers are oblong, ca. 4 mm long, flat, pubescent.
Mexican Sunflowers are blooming from September to November.
About 10 species are native to Central America and Mexico. 1 species introduced in China, cultivated in Yunnan, Guangdong and other provinces.
Mexican sunflowers are light-loving plants with a variety of habitats. They are found along large and small rivers, along highways, on wild hillsides, near villages, around farmland, on abandoned land, and in sun-facing forest Windows. Horizontal distribution is concentrated in the south of 24 degrees north latitude 10 points of tropical and south Asian tropical and subtropical regions, most of the average temperature distribution region is greater than 8.4 ℃, annual average temperature is greater than 16.0 ℃, annual rainfall is an area above 800 mm, the horizontal distribution zone, Mexican sunflowers distribution range is 100-2000 meters above sea level, and at an altitude of 1500 meters below the region is relatively concentrated, the size of the most common in milling in the hills.
Cuttage after survival for 3 times of short pruning, respectively in June, July, late August, the last pruning can not exceed September, otherwise affect the flowering period, after September only for thinning pruning.
In growing periods to control water, dry and wet combination. After cuttage survival, 1-2 times of dilute organic fertilizer water was applied in combination with pruning to promote branching and stem thickening from late August. From September to October, 0.2% potassium dihydrogen phosphate or calcium superphosphate were used for leaf topdressing to promote flowering.
Use of growth inhibitors. After each pruning, the new branches have 2-3 pieces of new leaves, with B9 or CCC spray top center, the concentration is 1000ppm-1500ppm. Spray again after 10 days, spray 6 times in total, and add 1 time in the middle and late September, so that the height of the plant can be controlled within 50 cm.
It takes 25 to 30 days for a flower to bloom until its seed matures. Sowing is actually sowing achenes. Achene ripe black brown, easy to fall off from the Fruit bowl, and we should pay attention to timely collection. Sowing is usually in March to April. Seed germination temperature should be above 15 degrees, such as 20-25 degrees, only 4-5 days can germinate, a month or so will start to branch. The percentage of seed germination is usually only 20 to 30 percent.
Mexican sunflowers close to the base of the stronger branches. In the growing season it has the characteristics of the occurrence of air adventitious roots, and the survival rate of these cuttings can reach 100%. The survival rate of cuttings was low, only about 20%. The cuttings are 10-20 cm long, leaving 2-3 buds to remove leaves, 15-25 long new roots. In spring, summer and autumn, it can be cut. Cuttings grow faster than seedlings. Mexican sunflowers, sown or cut in the spring, are ready to bear fruit that year.
Cuttage propagation can be carried out in mid-May. Take the strong lignified hard branches at the base of the plant as cuttings. The stem is 2-3 cm thick, lying directly on the surface of the soil in the basin, leaving 2-3 cm buds exposed. Keep the soil moist, and you can survive. Sand loam or yellow loam was used as culture soil. After survival, place in sufficient light for maintenance.
In Chinese folk, Mexican sunflowers stem leaves or roots are used as medicine to clear away heat and detoxify, dissipate heat and improve water efficiency, and are used for the treatment of acute and chronic hepatitis, hepatitis B, jaundice, cystitis, acne, carbuncle, toxic sores, diabetes, etc.
Mexican sunflowers rhizosphere can produce organic acid phosphatase and be released into the soil, increase the effectiveness of phosphorus, green manure after joining in the soil is broken down quickly, can improve the yield of corn, even without the presence of organic fertilizer. Mexican sunflowers can also promote the growth of maize root and root tillers, and the lack of phosphorus iron bauxite region, Mexican sunflowers organic matter quite content in the residue of the effect of N, P, K increased maize yield even more effective than chemical fertilizer also, and can increase soil moisture and improve soil physical properties,If with inorganic fertilizer used is the best choice to enhance soil fertility long-term. Mexican sunflowers even under the condition of the soil fertility exhaustion can accumulate high phosphorus and other nutrients. The addition of the green manure can complement the missing in the soil phosphorus, soil chinalco ions are Mexican sunflowers that absorb chelate with oxalic acid salt, and can avoid the aluminum poisoning in plants. The leaves of Mexican sunflowers contain up to 6.10% protein (dry matter basis), so it is a high-protein feed plant with potential value for feed development.