European crab apple (Malus sylvestris) is a plant species that can live to be one hundred years old. European crab apple is native to Europe and its latin name Malus sylvestris means forest apple. Caterpillars of the twin-spotted sphinx feed on the leaves of european crab apple. This species has been considered an important ancestor of the domestic apple.
I. Appearance and Characteristics
Malus sylvestris, the European crab apple, also known as the European wild apple or simply the crab apple, is a species of the genus Malus, native to Europe and western Asia. Its scientific name means “forest apple”.
The wild apple is a deciduous small to medium-sized tree, but can also grow into a multi-stemmed bush. It can live 80–100 years and grow up to 14 metres (46 feet) tall with trunk diameters of usually 23–45 centimetres (9–17+1⁄2 inches), although diameters exceeding 90 centimetres (35 in) have been recorded. The leaves are roundish-oval and sometimes hairy on the underside. The hermaphrodite flowers appear in May, slightly preceding hawthorn, have white or pinkish petals and are insect-pollinated. The small pome-fruits are around 3 centimetres (1.2 in) in diameter, ripen in autumn and fall to the ground. The bark is light brown and breaks up in flakes. The branches are thorny, especially in response to pruning or browsing.
European wild apples hybridise readily with domesticated apples. This can make identification difficult, as hybrids commonly exhibit traits that are transitional with respect to the two parent species. Generally, a reliable identification cannot be made without genetic testing, however, there are clues that can help identify individuals that are likely to be pure wild apples. Wild apple leaves tend to be somewhat smaller, stiffer and shinier.
In comparison to those of both domesticated and hybrid apples, the underside of wild apple leaves also tends to be less hairy, often lacking hairs altogether. The crown of wild apples is also densely branched, whereas the crown of domesticated apples tends to be more loosely arranged with fewer, straighter branches. Finally, wild apple fruits tend to be smaller. The apples are usually below the threshold of 3 centimetres (1.2 in) in diameter, while domesticated and hybrid apples tend to be above. None of these features is entirely conclusive, however, and the best field identification results from their combined utilization.
The European wild apple is dispersed primarily by mammals, which eat the fruits. In a study from Mols, Denmark, it was determined that cattle accounted for the bulk of dispersal, followed by horses, despite the presence of wild animals. In Britain, the crab apple is associated with 93 species of insect. Its leaves are food of the hawthorn moth (Scythropia crataegella).
II. How to Grow and Care
Sunlight
European crab apple prefers sunlight and grows well in full sun. Sufficient sunlight for about 8 hours a day is recommended. Sunlight will have a great impact on flower colors, while insufficient sunlight will lead to lighter colors. If there is strong light in summer, european crab apple needs proper shady conditions to avoid high-temperature injuries. Too much light may cause leaf curling or spots on stems and leaves.
Temperature
Widely distributed in the northern temperate zone, european crab apple is generally very adaptable to the distinct seasons, including hot summers and cold winters. It can tolerate temperatures as low as -30 ℃. European crab apple can’t tolerate extremely high temperatures in summer; temperatures above 32 ℃ will affect its growth. The tree is drought-tolerant and doesn’t require much water, hence, avoid over-watering it.
Watering
If European crab apple is planted in a courtyard, water it until water accumulates on the soil surface without seepage for an extended time. If it is planted in a flower pot, fill the tray under the flower pot with water to let the water slowly penetrate into the soil. About ten days after transplanting, water European crab apple again to promote growth. Watering thereafter should be based on external climate and soil conditions; there is no need to water when the soil is still moist. Water should be provided when the soil is relatively dry, but don’t water so much that it accumulates around the tree.
Watering once every 3-5 days in winter is generally advised. With sufficient sunlight in summer, european crab apple should be watered once every 1-2 days. Be careful not to provide too much water each time. The best irrigation time is in the morning or on sunny days. This timing can promote water absorption and root respiration in the case of transpiration during the day. Avoid watering on rainy days, as this can easily cause root rot.
Soil
European crab apple can adapt to various soils. The most suitable soil for growth is slightly acidic or neutral, humus-rich, loose, well-drained, and sandy. The best pH range for the soil is 6-8. During cultivation, the soil can be mixed with garden soil, peat soil, and organic fertilizer in a proportion of 6:3:1.
Fertilizing
European crab apple prefers fertilizer, and soil fertility will affect its growth and reproduction. It is best to apply sufficient base fertilizer composed mostly of organic fertilizer as well as some quick-acting fertilizer. Fertilizer application in fall produces the best results; it promotes rooting and accumulation of more nutrients for the following year’s growth. Additionally, there are two other recommended fertilization times: before spring buds and when the fruit begins to grow. Dig out a small soil ditch 30 cm around the trunk, and then add the fertilizer evenly, water thoroughly, and loosen the soil properly after drying.
Planting Instructions
It is generally easiest to plant european crab apple by buying seedlings rather than sowing seeds. The recommended planting time is before budding in early spring or after leaves fall in early winter. Before planting, thoroughly check whether the roots of the tree are healthy. If rotten roots are found, they need to be quickly cut and disinfected with carbendazim.
When planted in a garden, the pit depth should be about 40 cm and the diameter about 60 cm. If the root is large, the size of the pit needs to be twice as big as the root ball. Before transplanting, apply some rotten organic fertilizer as the base fertilizer. In severe cold zones, pay attention to keeping european crab apple warm while transplanting. Add a cover such as wood chips or mulch at the base of the plant to ensure it overwinters safely.
Pruning
Pruning is very important for european crab apple and is usually performed between late fall after its leaves drop and early spring before it sprouts. Pruning not only keeps branches scattered and maintains the tree’s shape, but also ensures ventilation and sunlight transmission, which is conducive to its growth. Promptly cut off dense, overlapping, thin, and infected branches, or prune out a suitable and aesthetic shape based on the viewing environment. When blooming, you can also cut off some branches and cut away withered flowers to promote budding and the blossoming of new branches.
When pruning and cutting longer branches, leave enough new buds for branches to grow better afterward.
Propagation
If there is a seedling growing at the root, you can cut the seedling from the plant before budding in spring or after leaves fall in autumn and winter. It is best to cut off the roots of the seedling and transplant them into new pots or dug pits.
III. Uses and Benefits
Compact in size and exploding with springtime blooms, european crab apple trees are considered a must-have in smaller gardens. They provide year-round interest with their pink spring flowers, summer fruits, fall foliage, and winter shape. European crab apple trees also provide pollination for other types of apple trees, further increasing their popularity.