Hawthorn

Crataegus monogyna Jacq.

Synonyms - Crataegus oxyacantha, Mespilus monogyna.

Family: Rosaceae

Names:

Crataegus is from the Greek kratos, meaning strength and refers to its stout woody nature.
Monogyna is from the Greek mono meaning one and gyne meaning female refers to the one seeded fruit.
Hawthorn is from Haw, the fruit, and thorn referring to its thorny branches.

Other Names:

Azzarola refers to its Spanish name.
May, Mayblossom and Maythorn refers to its use in the May Pole celebrations as it flowers in May in Britain.
Haw, Motherdie, Quickthorn, Singleseed Hawthorn, Whitethorn.

Summary:

A spiny, tall, erect, perennial, deciduous tree or shrub to 6 m high with small, 3-5 lobed leaves. Clusters of white to pink flowers produce small, round, red, fleshy fruits crowned by the withered sepals.

Description:

Cotyledons:

Two.

First leaves:

Leaves:

Alternate, variable shape, deciduous.
Stipules - Large and leafy usually.
Petiole - about 10 mm long.
Blade - Deeply divided into 3-7 lobes with rounded teeth. Triangular to egg shaped in outline.

Stems:

Erect, up to 6000 mm tall, usually 2000-4000 mm tall. Intricately branched with stout branchlets terminating in a spine and armed with 50-250 mm long thorns. The bark is smooth but may be roughened towards the base.

Flower head:

Compact flat topped clusters (corymb) at the ends of branchlets. Individual flowers on short stalks.

Flowers:

White to pink, 8-12 mm diameter, regular, fragrant,
Ovary - Inferior, attached to the hollow receptacle. Single seeded.
Style - 1, becomes bony as the fruit matures.
Sepals - 5, short, spreading.
Petals - White, cream or pink, 5, almost round, longer than sepals.
Stamens - Many.
Anthers - Many.

Fruit:

Red with yellow flesh, round, 8-10 mm diameter, fleshy with a very hard centre, crowned by the withered sepals. Made up of the ovary and receptacle.

Seeds:

Brown, hard, egg shaped, 5-7 mm diameter, 1 per fruit.

Roots:

Deep and spreading. Suckers after damage.

Key Characters:

Prickly woody shrub
5 petals
Single calyx
Carpel becoming a stone united with the fleshy, hollow receptacle.
Adapted from John Black.

Biology:

Life cycle:

Perennial deciduous tree or shrub. Seeds germinate in autumn and grow slowly in their first year. Flowering occurs annually in spring once the plant is 2-3 years old. Fruit ripens in summer and the leaves fall in autumn as temperatures drop. New growth appears in spring. Plants may live for up to 70 years.

Physiology:

Tolerant of shade and full sun. Once established it will withstand moderate drought. Tolerant of salty winds in coastal areas. Tolerates grazing.

Reproduction:

By seed.

Flowering times:

Spring.
September to November in SA.
May in Europe.

Seed Biology and Germination:

The germination of seed in enhanced after passing through birds.

Vegetative Propagules:

Re shoots readily from cut stumps and damaged roots.

Hybrids:

Hybridises readily with Crataegus laevigata to form fertile offspring usually.

Allelopathy:

Population Dynamics and Dispersal:

Spread mainly by birds that eat the fruit. Foxes, Possums and Wallaroos also spread it. Seed production is large and contamination of vehicles, produce and animals may cause minor spread. Intentional plantings are the most common cause of new infestations.

Origin and History:

Europe, Asia minor, Afghanistan, New Zealand.
Introduced as an ornamental and hedge plant by British settlers. It was in SA before 1839, NSW before 1843 and Tasmania before 1845. It was proclaimed a noxious weed Victoria in 1965. In Tasmania it is not usually invasive.
In folk lore, Hawthorn in the garden brought good luck, but in the house spelt disaster probably because the scent resembled the smell of death of the Great Plague in London. Flowers were used on Maypoles and head decorations in Britain.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC.
Widely distributed in the world and weedy in north-eastern USA and the south island of New Zealand.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Humid and sub humid temperate areas with an annual rainfall of more than 600 mm. Prefers colder areas.

Soil:

Prefers shallow stony soils.

Plant Associations:

Open grasslands, forest edges and areas where it has been planted as a hedge.

Significance:

Beneficial:

Ornamental.
Medicinal. Vitamin C has been extracted from the seeds. Cratioaegolic acid, a heart regulating agent, has been extracted from the bark. Leaves are used as a tea and tobacco substitute. Extracts are used in herbal medicine for stomach pains, dropsy and drawing splinters.
Used as a hedgerow fence and still widely used for hedges in Britain.
Provides stock shelter and nesting areas birds that are protected from cats and foxes.
The wood is used for joinery and walking sticks.
The rootstock is used on grafted pears in Europe.

Detrimental:

Weed of woodlands and roadsides.
Can form dense and impenetrable thickets, crowding out native plants.
Harbours vermin, especially rabbits.
Alternate host for Light Brown Apple Moth, Pear and Cherry Slug and Fire Blight bacterium of Apples and Pears.

Toxicity:

Potentially toxic but few field cases recorded.

Symptoms:

Lower milk yields from cows in Britain.

Treatment:

Legislation:

Noxious weed of VIC and SA.

Management and Control:

Seedlings can be manually removed.

Thresholds:

Eradication strategies:

Successful eradication relies on community action to remove all plants in an area to eliminate the seed available for spread by birds.
Small plants can be dug up. Larger plants can be cut down and the cut stumps painted immediately with neat glyphosate, 2,4-D amine or picloram(Tordon® 75-D®) to prevent re shooting. A tractor and chain is often used to pull the tops to one side so they may be more easily cut with a chain saw.
For effective manual removal of larger plants the main roots and crowns down to 100 mm need to be removed.
Overall spraying with triclopyr, triclopyr plus picloram, glyphosate or metsulfuron are providing some control but usually require repeated treatments. Basal bark application of triclopyr or triclopyr plus picloram is reasonably effective.

Herbicide resistance:

Biological Control:

Related plants:

Azzarola (Crataegus sinaica) has white downy hairs on the young branches and flower stalks, larger leaves, larger flowers (15 mm), larger apple flavoured fruit (10 mm) and few spines.
Crataegus crus-galli
Crataegus laevigata has more than one seed per fruit.
Crataegus oxyacantha
Crataegus phaenopyrum

Plants of similar appearance:

Blackberry (Rubus fruticosus) has small curved thorns and individual leaflets and composite berries that turn black.
Cotoneaster has similar red berries but no thorns and leaves without lobes.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P215. Photo.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P397. Diagram.

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #293.3.

Parsons, W.T. and Cuthbertson, E.G. (1992) Noxious weeds of Australia. (Inkata Press, Melbourne). P567-570. Photos.

Randall, J.M. and Marinelli, J. (1996) Invasive Plants. (Brooklyn Botanic Gardens Inc. Brooklyn). P51. Photo.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.