Crabapple is the traditional term for plants of the genus Malus with fruit measuring less than 5 cm in diameter (Fiala 1994). Crabapples include species such as Malus prunifolia Borkh., Malus spectabilis (Ait.) Borkh., and more, and are distributed mainly in the northern temperate zone (Li 1999). In China, because of the emphasis on germplasm resources, more and more new crabapple varieties with excellent ornamental performance have been selected by horticulturists. However, of all known crabapple cultivars, most ornamental traits are focused on flower color and shape, such as ‘Juan Zhulian’ (Zeng et al. 2022), ‘Fen Balei’ (Zhou et al. 2019), ‘Hongzi Die’ (Luo et al. 2025), and ‘Yunjuan Yunshu’ (Lu et al. 2023); and attractive foliage color, such as ‘Duojiao’ (Zhang et al. 2020). Currently, the breeding trend for crabapples continues to be to breed new varieties with unusual flower shapes, double petals, and novel flower colors, but their luscious display of fruit in autumn—and especially in winter—is particularly rare. We introduce the new crabapple cultivar Hong Shanhu, which has the excellent ornamental traits of fruit that remain bright red and persist through the winter. Moreover, this variety displays exceptional winterhardiness. The breeding of this variety will enrich the diversity of ornamental crabapple germplasm resources and provide more choices for landscaping in cold regions.

Origin

In Autumn 2006, ∼8000 seeds of the female parent Malus ‘Radiant’, which was open-pollinated by seven different taxa (Malus hupehensis Borkh., Malus baccata Borkh., Malus ‘Jiazi’, Malus ‘Xuehong’, Malus ‘Snowdrift’, Malus ‘Royalty’, and Malus ‘Xuehua’), were collected at the Fruit Tree Scientific Research Base of Shenyang Agricultural University, located in Shenyang, Liaoning Province, China. We placed these clean seeds in moist sand medium at 0 to 4 °C for more than 40 d until radicles emerged in Jan 2007. The germinated seeds were then planted in nursery plugs containing plug seedling substrate. After 40 d of cultivation, the healthy seedlings with six to seven leaves were transplanted into the base’s nursery with 35- × 50-cm spacing. In 2010, a variant individual seedling with beautiful flowers and attractive fruit was selected. We observed this superior line for 3 consecutive years (2011–14) until it showed stable traits. From 2015 to 2017, three generations of bud-grafted seedlings were propagated using M. hupehensis as the rootstock. All the grafted plants displayed the same phenotypic characteristics of all test traits. Because the fruit of the superior line looks like the gem known as red coral in autumn and winter, we named it ‘Hong Shanhu’ (the Chinese pinyin for red coral is Hong Shanhu).

Description

The morphological traits of the grafted cultivar ‘Hong Shanhu’ at 7 years old were observed, and they were different from its female parent in tree habit, flower shape, diameter, and color; leaf apex and length; fruit shape and weight; and other characteristics (Table 1). The distinguishing characteristics of ‘Hong Shanhu’ are a large amount of red-purple flowers and a very high fruit setting rate (Fig. 1A). The physiological fall of fruit is extremely light, and the fruit persist throughout the winter in a full state (Fig. 1B), which shows excellent ornamental value and long ornamental time in the northern cool climate zone (annual average temperature, 6.2 to 9.7 °C; January average temperature, –12 to –10 °C; annual average precipitation, 600–800 mm). All colors were referenced to the Royal Horticultural Society (RHS) colour chart (Royal Horticultural Society 2015). The specific properties of ‘Hong Shanhu’ are described next.

Table 1. Comparisons of the main morphological characteristics between Malus ‘Radiant’ and Malus ‘Hong Shanhu’.

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Habit.

Young ‘Hong Shanhu’ trees exhibit a fastigiate growth habit. With increasing tree age, the tree becomes rounded. Branches are gray (RHS N200B) under normal growing conditions (Table 1). The average length of the twig internode length is 2.56 to 2.91 cm, and 82.61% of the branches are short bearing branches (< 5 cm).

Foliage.

‘Hong Shanhu’ breaks dormancy in late March in Shenyang, China. The new expanding leaves are gray-red (RHS 182B), and the mature leaves are obtuse and green (RHS 141C) with a length of 5.21 to 6.75 cm and a width of 3.28 to 4.83 cm (Table 1; Fig. 1E). The leaf margin is serrated and the petiole length ranges from 1.64 to 2.92 cm (Table 1). In autumn, the leaves naturally turn yellow and then fall off. ‘Hong Shanhu’ enters dormancy in early November in Shenyang.

Flower.

As shown in Table 1, the initial bloom of ‘Hong Shanhu’ occurs in late April in Shenyang, China. Each umbrella-shaped inflorescence has four to six flowers (Fig. 1C, b and c). The flowers exhibit a moderately deep cup shape and ovate petals. Fully open flowers have an average diameter of 3.08 to 3.71 cm. The buds are red-purple (RHS 59A) (Fig. 1C, a), and the surface and back of the petals are red-purple (RHS 61B) with a folded surface (Fig. 1C, d and e).

Fruit.

‘Hong Shanhu’ exhibits a heavy annual fruit set. In late September, the fruit mature to red (RHS 46B) and are small (horizontal diameter, 1.22–1.51 cm; longitudinal diameter, 1.39–1.71 cm), with an ellipsoid shape (Fig. 1D, d). The fruit stalk is 1.75 to 2.42 cm long and its fruit flesh color is orange (RHS 26C) (Table 1).

Cultivation

‘Hong Shanhu’ demonstrates good environmental adaptability. It can be cultivated successfully in regions with a minimum annual temperature of –25 °C. It is suitable for growing in full sun and prefers sandy loam with fertile soil and adequate moisture. ‘Hong Shanhu’ is mainly propagated by bud grafting using M. baccata, M. hupehensis, and M. prunifolia as rootstocks, with a diameter ranging from 0.5 to 2.5 cm. When grafting, scion buds were collected from healthy 1-year-old branches and were inserted into a T-shaped cut in the bark of the rootstock. Subsequently, the buds were wrapped tightly with plastic strips to prevent water loss. The buds of successful grafts turn light green after 7 d. The survival rates of ‘Hong Shanhu’ can reach more than 90%.

Availability

‘Hong Shanhu’ is available from Shenyang Agricultural University.