Quick Facts

Quick facts

• Originally from Europe and Asia, Hawthorn (Crataegus monogyna) is a low many branched arching winter deciduous tree or tall shrub to 6 m tall and wide, with lobed leaves 6×7 cm long, many clusters of pink to white flowers, and many obvious red fruits.
•  that is widespread in cool temperate to humid regions in the Australian Capital Territory, New South Wales, Victoria, Tasmania and South Australia.
• It has been widely used as a hedge plant, and forms thickets along roadsides, in grasslands, open woodlands, and pastures.
• The dense thickets formed by Hawthorn can displace native plant species, reduce native understory regeneration, prevent access to larger fauna, and inhibit stock grazing.
• It produces abundant red fruit that are eaten and dispersed widely by birds and mammals.
• Hawthorn poses a threat to native bushland and could have long term implications for native plant community structure.
• Can be controlled by mechanical means and herbicides normally applied to cut stems. 

What Does It Look Like?

What is it?

Hawthorn (Crataegus monogyna) is a dense, deciduous low-branched tree or tall shrub, usually 2–6 m tall. The stems are covered with stout woody thorns 0.5 to 2.5 cm long. The young, twigs sparsely hairy, loosing leaves as the age with 1–2 year old twigs normally with a waxy covering. Leaves are thick and leathery, alternate arranged, with two different types of shoots present, elongate and short shoots. All leaves have lobed, ovate (shaped like a section through the long axis of an egg and attached by the wider end) to obovate (shaped like a section through the long axis of an egg and attached by the narrower end) and cuneate (wedge-shaped; with straight sides converging at base in outline), with 3–7 lobes, each with 1–7, sometimes to 12 teeth. Leaves produced on the old woody short and flowering shoots are 1.5–6 cm long and 1–6 cm wide. Leaves produced on the vigorous elongate vegetative shoots are widely spaced and slightly larger at 2–7 long and 2–7 cm wide. Leaves above are fresh green with a few long hair to no hairs, leaves below are lighter green have long hairs along major veins, and in the axis of main and secondary veins, with petiole leaf stalk 1–2.5 cm long. Leaf-like appendages often occur at the base of the leaves but are soon lost only seen when the leaves are produced in spring.

Flowers are produced in dense clusters of 8–15, produced towards the tip of short leafy stems along the branches. Flowers are white, cream or pink, with 5 petals, 8–12 mm in diameter towards the tips of branches, surrounded by 5 green reflexed sepals. The flowers have 15–20 male stamens with light purple anthers, (pollen producing male organ), and a female one carpel with 1 sometimes 2 styles.

Fruits are fleshy, firm, 'berries', red to deep red when ripe, and up to 1.1 cm long and 0.5–1 cm wide either berries near rounded or twice as long than wide. The 'berries' enclose a single or sometime but rarely two hard brown seed. Berries develop on the flower stalk (Parsons 1973; Symon 1986; Parsons & Cuthbertson 2001, Navie 2004; Richardson et al. 2006; Robertson 2006).

For further information and assistance with identification of Hawthorn contact the herbarium in your state or territory.

Flower colour

White, Pink

Growth form (weed type/habit)

Tree, Shrub

Where it currently grows? Preferred habitat

Hawthorn occurs in humid and subhumid to temperate cool regions in Australia, and grows well in most soils and shallow stony sites, particularly in areas with an annual rainfall over 600mm (Parsons & Cuthbertson 2001). It is widespread in cooler districts of south-eastern Australia (Richardson et al. 2006), and as it is used widely as a hedge plant, it is commonly found along roadsides in road reserves of native and introduced vegetation, forest margins, and poorly managed pastures (Parsons & Cuthberson 2001). It also forms thickets along waterways, in grasslands, and in open woodlands (Navie 2004; SGA undated).

Are there similar species?

Hawthorn is similar to Azzarola (Crataegus x sinaica) [as C. sinaica],  azarole (Crataegus azarolus), and the American Hawthorns smooth hawthorn (Crataegus laevigata; Crataegus crus-galli; Crataegus phaenopyrum)

Azzarola (Crataegus x sinaica)but the latter species has relatively large fruit (10–25 mm across), 2–3 large seeds per fruit (as opposed to a single seed per fruit in C. monogyna), and young stems that are [always] covered in soft hairs (Navie 2004).

Azarole (Crataegus azarolus) is a spineless plant with relatively large, yellow-orange, fruit (up to 20 mm across) that usually contain two or three hard 'seeds' (i.e. pyrenes). Its young stems are covered in soft hairs (i.e. they are pubescent).

The American Hawthorns including; Crataegus crus-galli; Crataegus phaenopyrum. These are spiny plants but with spines 6–10 cm long with slightly bigger  scarlet red, fruit 6–15 mm across; always containing two hard 'seeds' (i.e. pyrenes).

Hawthorn is also similar to the Cotoneasters (Cotoneaster species.), but these species have leaves with entire margins, and do not have spines (Symon 1986). Hawthorn is also similar to the Firethorns (Pyracantha species). However, Firethorns have leaves with entire or finely toothed margins, and are not lobed (Navie 2004).

Why Is It A Weed?

What are its impacts?

Hawthorn has invaded forests, woodlands and riparian areas throughout south east Australia (DPI NSW 2019). May forms infestations on roadsides and in disturbed bush where it can compete with native regrowth and form spiny thickets that harbor rabbits. In Victoria, it has been found that may can spread over neglected perennial pastures from former hedge plantings and in this situation it would cause a similar problem to weedy Blackberries and briars (wild weedy roses) (Government of South Australia 2021).

Native ecosystems: Widely used as a hedge plant, Hawthorn can spread away from plantings during favorable conditions into native grasslands, woodlands, forest areas, and poorly managed pastures. These dense patches can also provide cover for pest animals such as rabbits (Parsons & Cuthbertson 2001). Hawthorn can displace native species in remnant grassy vegetation in farming areas, can shade-out native flora, and adversely affect the growth and regeneration of over-story plants (Muyt 2001; Miles undated). Dense stands can also inhibit the movement of large fauna, and can significantly reduce available habitat (Muyt 2001; University of California undated). Hawthorn may therefore have long term impacts on native plant community structure, and poses a threat to bushland, reserves and conservation areas (Tamar Valley Weed Strategy 2001).

Agriculture: It can form dense stands that reduce grazing capacity of stock due to exclusion and as the spines act as a deterrent. Seedlings of Hawthorn rarely establish in pastures that are regularly grazed (Tamar Valley Weed Strategy 2001). Due to the presence of hydrocyanic acid in some Crataegus species, Hawthorn is potentially hazardous to grazing stock (Parsons & Cuthbertson 2001). Hawthorn can be a reservoir for the fire blight bacterium that affects apple and pear crops (Parsons & Cuthbertson 2001), and can host light-brown apple moth (Holding & Bowcher 2007). Dense patches of may provide good cover for rabbits and other pests. In the British Isles, May and other hawthorns are an important reservoir of the fire blight bacterium, which affects pears and apples. May also is known to host Mediterranean fruit fly and light brown apple moth (Government of South Australia 2021).

How does it spread?

Hawthorn produces and is spread via the large number of seeds contained in the small fleshy red fruits, which are dispersed to new areas by birds and mammals (foxes, possums and wallaroos) which eat the fruit. Hawthorns are capable of producing suckers after a disturbance (Parsons & Cuthbertson 2001; Robertson 2006) but this is not a common. Seeds can also be dispersed by water (Navie 2004). Germination success is said to increase when the seeds passes through the digestive tract of birds, which can disperse seeds widely (Parsons & Cuthbertson 2001; SGA undated). Conversely, seed viability can be reduced somewhat when fruits are eaten and defecated by possums, which have been found to move seed between 0 and 50 m from the parent plant (Bass 1990). Possums are potentially an important disperser of seeds into native areas (Bass 1990). The fruit can contaminate farm machinery, vehicles, agricultural produce, and garden waste, but these vectors are thought to be of little significance for its spread (Parsons & Cuthbertson 2001; Navie 2004).

What is its history in Australia?

Hawthorn was most likely brought to Australia by early settlers as a garden ornamental or hedge plant (Parsons & Cuthbertson 2001). It is recorded as being advertised for sale as a garden plant in South Australia in 1839, and could have been present in other states at this time (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Non-chemical control: Hawthorn seedlings can be controlled by pulling or grubbing (Robertson 2006). Larger plants can also be removed mechanically, but regrowth can occur unless the entire crown and the top few centimetres of root are removed (Parsons & Cuthbertson 2001) so chemical treatment helps  kill plants.

Chemical control: The trunks of large plants can be drilled and filled with herbicide, or can be cut near the ground and the base painted or swabbed with herbicide. Overall spraying of Hawthorn plants is not reliable (Parsons & Cuthbertson 2001; Robertson 2006), but small plants are susceptible to spot spraying.

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Hawthorn germinates in autumn. Early growth is slow, and plants do not flower until the second or third year (Parsons & Cuthbertson 2001). Flowers are produced mainly in early spring, but sometimes into early summer (Navie 2004). Fruit ripen in summer, when the branches can be laden with red berries (Robertson 2006), and the leaves are shed as temperatures fall in autumn and winter. New growth is produced the following spring. Hawthorn is a long lived plant, and can potentially live for more than 70 years (Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, QLD, SA, TAS, VIC

What areas within states and territories is it found?

Hawthorn is widely distributed in south Eastern Australia. In New South Wales it most often occurs in south-eastern regions (Navie 2004) normally away from the coastal areas occurring in cooler higher rainfall areas. It is widespread in southern Victoria, particularly east of Melbourne, and in the North-East and North-Central regions (Parsons 1973). In South Australia, it occurs commonly in the Adelaide hills and is recorded from the Clare wine region and the lower south-east (Parsons & Cuthbertson 2001; Robertson 2006; AVH 2021). Despite its widespread occurrence in Tasmania as a hedge plant and ornamental, it is not thought to be particularly problematic in this state (Parsons & Cuthbertson 2001). It has been recorded from south-eastern Queensland, and is naturalised in the Wallangarra area in the southern Darling Downs district (Stanley & Ross 1983; Navie 2004).

Where does it originate?

Hawthorn has a very wide native range in western Europe, the Mediterranean region, Asia Minor and Afghanistan (Parsons 1973; Parsons & Cuthbertson 2001). It is considered weedy in several countries including Australia, north-eastern United States, where it occurs widely (GRIN 2007; USDA 2007), and New Zealand, where it is occasional but widespread on the North and South Islands and Stewart Island (Parsons & Cuthbertson 2001; Roy et al. 2004).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

ACT, SA, VIC

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Crataegus monogyna

Other scientific names (synonyms)?

• Crataegus monogyna Jacq. subsp. monogyna
• Crataegus monogyna subsp. nordica Franco
• Crataegus oxyacantha L.
• Mespilus monogyna (Jacq.) All.

Does it have other known common name(s)?

Singleseed Hawthorn, English Hawthorn, May, May Hawthorn, Red Hawthorn, White Hawthorn, Whitethorn