Magnolia cavalerier (Finet & Gagnep.) Figlar var. platypetala (Hand-Mazz.) Noot., broadpetal Michelia, is an evergreen tree of Magnoliaceae. The old genus Michelia, now a section of Magnolia, is native to China and widely distributed in Hubei, Hunan, eastern Guangdong, Guangxi, Guizhou, and Yunnan. The plant was introduced to the United States more than 200 years ago and is widely cultivated in warmer regions (Dirr 2010; Li et al. 2017). Broadpetal Michelia has a strong adaptability in its distribution areas. It is an excellent ornamental plant as a specimen planting and shade tree. During production, the plant also performed well in both container and field conditions (Li et al. 2017). The species has a pyramid habit and dense branches. A 20-year-old tree can reach up to 20 m tall and 50 cm in diameter. The plant has gained market popularity, especially the new cultivars with colorful flowers and earlier blossom traits.
Most species in Michelia section have the characteristics of loads of fragrant flowers, which are welcomed in landscapes and beloved by gardeners. There are more than 20 cultivars of Section Michelia, such as ‘Yunrui’ (Xu et al. 2014), ‘Mengxing’ (Shao et al. 2016), ‘Jinxiu’ (Huang et al. 2016), and ‘Fenyun’ (Hu et al. 2022). These cultivars are characterized by white or light-colored flowers, such as cream white and light yellow, and few of these cultivars had dark-colored flowers, such as purple flowers (Chai et al. 2018). The new cultivar, Red Elegance was bred by the Central South University of Forestry and Technology. The plant was selected from a wild-collected seedling population. Its most attractive features are the light reddish-purple for both outer and inner perianth. The plant is a tree with fragrant flowers that blooms in late January or early February (Fig. 1).
Habit and blossom of Magnolia cavalerier (Finet & Gagnep.) Figlar var. platypetala (Hand-Mazz.) Noot. ‘Red Elegance’.
Citation: HortScience 58, 1; 10.21273/HORTSCI16867-22
Origin
In Winter 2008, a group of 128 broadpetal Michelia seedlings were collected from Tongdao County (Hunan, China) and planted in the Magnolia Garden of Hunan Forestry Science and Technology Demonstration Gardens in Changsha, China. The plants began to flower in Spring 2009. One early-flowering individual (end of January) was observed and selected from this group of seedlings. Its tepals were reddish-purple and gradually deepening in color. Both the outer tepals and the inner tepals were reddish-purple. From 2010 to 2013, we evaluated this plant yearly and concluded that the characteristics of early flowering and gradual change of perianth from light red-purple to red-purple from outside to inside were stable. We named it ‘Red Elegance’ because the flowers looked like red birds landing on the tree and the tepals were delicate and elegant (Figs. 1 and 2). From 2013 to 2017, we grafted ‘Red Elegance’ branches on rootstocks of Magnolia denudata each year and we selected 68 health and vigor grafted plants for further evaluation. In Spring 2015, the first generation of grafted plants began to flower and all of the grafted plants bloomed in Spring 2018. All flowers of the grafted plants showed the same color as the original selected individual, confirming the inheritance of ‘Red Elegance’. All grafted plants during 2013 to 2017 showed vigorous growth, good adaptability, and no serious diseases and pests.
(A) Full open flower of Magnolia cavalerier var. platypetala ‘Red Elegance’. (B) Flower, tepals, and androecium, and gynoecium colors of M. cavalerier var. platypetala (top), ‘Fenyun’ (middle), and ‘Red Elegance’ (bottom).
Citation: HortScience 58, 1; 10.21273/HORTSCI16867-22
Description
The unique ornamental characteristics of ‘Red Elegance’ are that the tepals from the outside to inside are from light red-purple to red-purple and the habit is a pyramid (conical shape). Among the published cultivars, Fenyun has the most similar traits to Red Elegance (Hu et al. 2022). Both cultivars are selected from M. cavalerier var. platypetala and have the similar characteristic of early flowering. But the habit of ‘Red Elegance’ is conical, whereas that of ‘Fenyun’ is nearly spherical. ‘Red Elegance’ tepals are light red-purple on the outer layers and red-purple on the inner layers (Fig. 2), whereas ‘Fenyun’ tepals are red-purple only at the base of the outer layers and white above, half red-purple and half white for inner layers (Table 1). In addition, the corolla shape of ‘Red Elegance’ is a shallow cup with diameter of 6.1 to 6.7 cm, whereas ‘Fenyun’ is a cup with diameter of 4.2 to 5.4 cm ( Table 1, Fig. 2).
Comparisons of characteristics among Magnolia cavalerier (Finet & Gagnep.) Figlar var. platypetala (Hand-Mazz.) Noot. and its two cultivars of Red Elegance and Fenyun.
Habit and foliage.
‘Red Elegance’ is an evergreen broad-leaved tree, with upright pyramid growth habit (Fig. 1). Leaves are leathery and green, oblong or elliptic-oblong, 14.0 to 22.0 cm long and 5.1 to 7.2 cm wide, with a short petiole 1.0 to 1.3 cm in length. Shoots and leaf buds are covered with gray fluffy hairs.
Flower.
This new cultivar is loaded with flowers, almost one on each node. There are two bracts on each flower covered with densely reddish-brown sericeous hairs (Table 1). There are 9 to 12 tepals, divided into three to four whorls, forming a shallow cupped corolla (Table 1, Fig. 2). The outer tepals are obovate-elliptic or elliptic, 5.0 to 5.6 cm long and 2.0 to 2.5 cm wide, middle whorl slightly narrow, inner whorl narrowly ovate-lanceolate to 1.2 to 1.4 cm wide. The outer tepals are red-purple 69B (Royal Horticultural Society 2015) and the inner tepals are red-purple 73A (Table 1, Fig. 2). Stamens are usually ≈30, 2 to 3 cm long, and grayed-purple anthers (185C) 6 to 8 mm long (Fig. 2). Gynoecium is above the androecium, cylindrical, 6 to 8 mm in length, and yellow-green (N144B) in color. The gynoecium stalk is ≈5 mm. Aril is reddish and seeds are broadly oblate or oblong, 5.5 × 9.5 mm. The blossom (10% open flowers) starts at the end of January and the beginning of February in Hunan, China (Table 1).
Propagation and Cultivation
‘Red Elegance’ is regenerated mainly by grafting during the spring season from late February to early March in Hunan, China. We had grafted one bud scion wood to the four rootstocks [Magnolia denudate Desr., Magnolia liliiflora Desr., Magnolia chapensis (Dandy) Sima, and Magnolia maudiae (Dunn.) Figlar] and resulted in 63% or higher successful grafting rate. We used completely randomized designs with three replicates and 20 grafted plants per treatment (rootstock) per replicate. Data were analyzed using Microsoft Excel (version 2022). The better rootstock should be M. denudata and M. cavalerier var. platypetala, which yielded 83% or higher grafting success rate (Table 2). In terms of season of grafting, early spring (March in Hunan, China) is recommended (Table 3). Similar calipers of rootstock and scion wood should be selected for the side veneer grafting. The vigor and healthy scion wood with one dominant bud is recommended. After the new scion wood bud is sprouting and growing, we should remove any shoots from the rootstock. The nursery beds for grafting liners should be kept clean with no weeds and proper fertilization. By the end of the growing season, the graft tapes should be removed to avoid any girdling. Rooting of stem cuttings had been trialed without luck. For regenerating of ‘Red Elegance’, we recommend the side veneer grafting in March with M. cavalerier var. platypetala or M. denudate as the rootstock.
Grafting successful rate of Magnolia cavalerier var. platypetala ‘Red Elegance’ to four rootstocks (three replications with 20 plants per root stock per replication).
Grafting successful rate of Magnolia cavalerier var. platypetala ‘Red Elegance’ with Magnolia denudata as the rootstocks at different seasons (three replications with 20 plants per month per replication).
This new cultivar grows well in a warm and humid climate with temperature range from 15 to 32 °C. The plant can tolerate up to 40 °C and lower to −10 to −15 °C (Li et al. 2017). Semishade is preferred for seedling establishment and full sun guaranteed more flowers at maturity. Planting sites should have deep, well-drained, and acidic soil and container production should be with fertile and organic-rich media.
Availability
M. cavalerier var. platypetala ‘Red Elegance’ is available for restricted test trial only. Please contact Xiaoling Jin, College of Landscape Architecture, Central South University of Forestry and Technology, Changsha, China 321004 for grafted plants (20040197@csuft.edu.cn).
References Cited
Chai, Y.-X., Hu, X.-J., Zhang, D.-L., Liu, X.-L., Liu, C.-X. & Jin, X.-L. 2018 Studies on compatibility of interspecific hybridization between Michelia crassipes and M. figo, M. maudiae, M. platypetala Acta Hortic. Sinica 45 10 1970 1978 https://doi.org/10.16420/j.issn.0513-353x.2017-0779
Dirr, M.A. 2010 Manual of woody landscape plants 6th ed. Stipes Publishing Champaign, IL, USA
Hu, X.-J., Jin, X.-L., Xing, W., Zhang, Z., Li, W.-D. & Huang, G.-L. 2022 A New Michelia platypetala Cultivar ‘Fenyun’ Acta Hortic. Sinica 49 7 1619 1620 https://doi.org/10.16420/j.issn.0513-353x.2020-0363
Li, R.-X., Jin, X.-L., Hu, X.-J., Chai, Y.-X., Cai, M.-Y., Luo, F. & Zang, F.-J. 2017 Analysis and comprehensive evaluation on cold resistance of six varieties of Michelia Chinese J Appl Ecol. 28 5 1464 1472 https://doi.org/10.13287/j.1001-9332.201705.039
Huang, L.-B., Dou, Q.-Q., Dong, X.-Y., Zhang, M. & Li, X.-C. 2016 A new variety of Michelia maudiae ‘Jinxiu’ Scientia Silvae Sinicae 52 9 154 https://doi:10:11707/j.1001-7488.20160919
Royal Horticultural Society 2015 RHS colour chart 6th ed. Royal Horticultural Society London, UK https://www.rhs.org.uk
Shao, W.-H., Jiang, J.-M. & Dong, R.-X. 2016 A new Michelia cultivar ‘Mengxing’ Acta Hortic. Sinica 43 6 1219 1220 https://doi.org/10.16420/j.issn.0513-353x.2015-0888
Xu, H.-Y., Li, W.-X., Pan, Y.-Z. & Gong, X. 2014 A new Michelia cultivar ‘Yunrui’ Acta Hortic. Sinica 41 2 403 404 http://doi.org/10. 16420/j.issn.0513-353x.2014.02.021