monogyna – one seed in each fruit

Native range: Europe, N. Africa, W. Asia

Leaves:

• alternate
• simple
• ovate to diamond-shaped
• pinnately lobed with 3-7 lobes, w/ veins extending to the points of lobes as well as sinuses
• sinuses go most of the way to the midvein
• stipules

Flowers:

• inflorescence – flat topped cluster (corymb)
• radial
• perfect
• white
• 5 sepals, fused at base
• 5 petals
• many stamens, often with purple pollen.
• 1 style
• inferior ovary
• insect pollinated (bees)

Fruit:

• pome (also called a haw)
• one hard-shelled seed
• red
• 1/4–1/3”

Other characteristics:

• deciduous tree or shrub to about 30 ft
• branchlets somewhat spiny

Relevant info:

• birds like fruit
• common in the English countryside as a roadside hedge
• C. monogyna was introduced early to North America to be used for agricultural hedges, a practice now discontinued on this continent
• naturalized in the PNW
• other Crataegus spp. have pink flowers
• C. douglasii is native to PNW

Ecology & Adaptations:

• native to forest understories of Europe, northern Africa, western Asia
• naturalized in the PNW and invasive in local urban forests, riparian areas, abandoned fields and pastures, shrub lands and grasslands, and oak woodlands
• occurring chiefly west of the Cascades crest in Washington, less common in southeast corner of the State
• Alaska south to California, in other scattered locations in western North America, and widely distributed in eastern North America
• invasive in local urban forests prolific seed producer and can form dense thickets which exclude all understory plants
• can hybridize with native hawthorn species such as the black hawthorn (C. douglasii) found in the west
• seed dispersal – produces abundant red berries are attractive to robins and possibly other birds and animals, which help spread this tree far beyond where it is planted.
• disease resistance – compounds in its tissues render the species resistant to many diseases of Crataegus, e.g. rust.
• control:
  • not regulated but recommended in natural areas that are being restored to native vegetation and in protected forest lands and wilderness areas
  • seedlings and young saplings can be pulled or dug up when soil is moist, but roots quickly become deep and stout, and sharp thorns are present even on young seedlings
  • mature trees have deep and extensive roots so digging is labor-intensive and results in considerable soil disturbance if all of the roots are removed
  • often sprouts from stump, so removal by cutting alone is not usually effective
  • applying herbicide with the cut stump or frilling method is most effective approach for plants that cannot be removed by digging or grubbing out the roots