The thorns are very useful and ornamental small, hardy trees mostly with widespreading and dense twiggy heads; spring flower, mainly white, is followed in the autumn by attractive haws. Equally at home in city street or exposed coastal or moorland garden, and on all soils, they are deserving of wider planting.
Crataegus crus-galli, the cockspur thorn, is a particularly worthwhile species from eastern North America making a flat-topped picturesque tree. It is a copious flowerer, notable for both brilliant red autumncolour and for the crimson haws which often persist until spring. The hybrid C. lavallei (carrierei) makes a splendid small garden tree; both glossy green and orange-red fruits persist until the New Year making an attractive and unusual winter feature.
A form of the common hawthorn, C. monogyna stricta (fastigiata) with a narrow, erect-growing branch system, is particularly useful in cold windswept sites. C. oxyacantha is the European and British native hawthorn or May, and it has given rise to a number of varieties or hybrids some with double and colouredwhich form excellent small garden trees with compact heads. Paul’s Scarlet is a double red; plena, double white, and roseaflore pleno, a lovely double pink.
C. phaenopyrum, the Washington thorn, is one of the most outstanding of the American thorns; a handsome round-headed tree with shining maple-likewhich colour well in autumn and masses of scarlet haws often persisting until spring.
C. pinnatifida major from northern China is perhaps the most effective of all thorns in respect of its rich autumn leaf colour and hanging clusters of large glossy deep red berries.
C. crusgalli, cockspur thorn, is a broad tree, 4-6 m tall, with oval, slightly serrated leaves which are not hairy, clusters of 15-20 whiteand red fruits. C. laevigata (syn. C. oxyacantba), May hawthorn, is a tree up to 4 m tall with two or more trunks, reddish-brown, slightly hairy , thorns up to 2.5 cm long, broad, oval leaves with 3-5 short, serrated lobes, white umbels of flowers and red fruits; ‘Alboplena’ is a broad variety with double, white flowers turning pink; ‘Gireoudii’ has young, yellow and pale pink , shiny, dark green leaves which turn scarlet in autumn, and large, red fruits; ‘Paul’s Scarlet’ is up to 7 in tall, with double scarlet flowers; suitable as specimen shrub or tree in a park or avenue. C. x lavallei is 5-7 m tall, and grows in a compact, moderate way. It has reddish-brown stems, thorns up to 4 cm long, oval, shiny green leaves, 6-10 cm long, which are not indented and later turn reddish, large white flowers and orange fruits up to 2 cm across.
C. monogyna, common hawthorn, is a single-trunked hawthorn, 5-8 m tall, with straight thorns, deeply indented leaves, consisting of 3-7(-9) slightly serrated lobes, white flowers and edible, dull red fruits; ‘Compacta’, a dwarf shrub, is up to 40 cm tall and broad, and grows in a spherical shape; ‘Stricta’ grows in a pillar shape. C. orientalis is up to 5 m tall, with diamond-shaped or oval, hairy, grey, deeply indented leaves, consisting of 5-7(-9) slightly serrated lobes, compact, white clusters of flowers and orangey-red fruits up to 2 cm across.
C. x prunifolia is 4-6 m tall, and has olive-brown stems, broad, oval, greatly serrated leaves, 5-10 cm long, which turn orangey-yellow in autumn, clusters of white, felted flowers and bright red fruits; ‘Splendens’ has a very broad crown and numerous dark red fruits; suitable as a loose hedge.