genus that includes 100-150 species of shrubs or small deciduous trees, originating in Europe, northern Africa, Asia and North America; generally they are cultivated as bonsai C. monogyna and C. oxiacantha, and also cultivars with flowers with decorative shades. It has vigorous growth, but quite slow; the stem is erect, very branched and the crown tends to be roundish or pyramidal; the bark is brown-orange, cracked and flaky in specimens of some years. The leaves are bright green, lighter on the lower side, have a lobed margin, with 3-5 little pronounced lobes. The plants at least 10-15 years old in spring produce numerous small flowers with five round petals, white or pink, gathered in terminal inflorescences; in autumn the flowers give way to small roundish drupes, of red color, which remain on the plant until the end of winter, containing a single seed. This plant is very suitable to be cultivated as bonsai, since it is quite easy to grow, it is resistant to adversity, it has decorative flowers and leaves which naturally tend to be small in potted specimens. Hawthorn is not very suitable for beginners, as the branches and foliage are very disciplined to have a harmonious bonsai.
Pruning, exposure and watering
Pruning: the most vigorous prunings are practiced after flowering or at the beginning of winter. Throughout the growing season, from March to October, it is possible to trim the young branches, leaving 2-3 leaves; if desired it is also possible to let the new branches grow and vigorously mingle them in June. The wire is applied from March to September; the new branches tend to grow upwards, so it is advisable to intervene early with the wire to conform the crown well.
Display: place the hawthorn in a sunny position, or in partial shade. In the months of July and August it is good to shade the foliage, to avoid excessive heat; it does not fear the cold, therefore it does not need protection in winter.
Watering: from March to September water regularly and abundantly, every 2-3 days; in the summer months intensify the watering, avoiding to leave the soil dry for long periods of time. In winter water about once a week. In the vegetative period, fertilize the plant every 10-15 days, providing a fertilizer rich in nitrogen in spring, phosphorus in autumn.
Hawthorn - Crataegus: Other tips
Soil: the crataegus prefers loose, rich and well-drained soils, use a mixture consisting of a part of peat, a part of sand and two parts of clay; this plant develops without problems even in garden soil mixed with a small part of sand or incoherent material, to improve drainage. Repot the young plants every year at the end of winter; adult specimens are repotted every 2-3 years.
Pests and diseases: crataegus particularly suffers from the attack of rust and powdery mildew; sometimes the aphids ruin the inflorescences.