Species profile: Oneseed hawthorn

Unfortunately for me, most of my interactions with invasive species are with the thorny kind, but mechanical plant defenses are no match for an invasivore.

Interstate-5 runs the height of the United States beginning at the Canadian border in Washington and ending at the Mexican border in California.  If you have driven on this highway anywhere from Washington to northern California, you have probably, at one point, looked out the window and unknowingly seen many trees or shrubs that go by the name Crataegus monogyna or are commonly known as the oneseed hawthorn.

Considered invasive in the United States, the oneseed hawthorn can be found in the Northeast and the Pacific Northwest (green = states with oneseed hawthorn records). Image credit: USDA plants

Beautiful but dangerous

In the mid to late spring, the tree produces beautiful clusters of white blossoms.  In the late summer and early fall, each tree produces many of clusters of small red fruits and can be quite striking.  Because of its aesthetics, the oneseed hawthorn was intentionally introduced into the United States from Europe as a cultivated ornamental tree.  They are dangerous from both a biological and physical standpoint.  According to the USDA, it is considered invasive in the lower 48 states, Alaska, and Canada and can be propagated through cuttings and roots, but predominantly through seeds.  One notable environmental impact of the invasive oneseed hawthorn trees is its competition with native flora for space and nutrient resources.  In addition, oneseed hawthorn branches are aptly named because they produce haws and are covered in thorns.

A non-native intruder followed by a native pest

Native to the eastern United States, it is unknown if it is an intruder in the West. Photo credit: S. Sim

Shortly after its introduction to the west coast of the United States, oneseed hawthorns became infested with an agricultural pest native to the eastern United States, Rhagoletis pomonella, otherwise known as the apple maggot.  The native range of the apple maggot has been documented to include Mexico and the southern and eastern United States.  However, it has recently been hypothesized that the apple maggot could also be native to the western United States and Utah, historically infesting the native river or black hawthorn, Crataegus douglasii Lindl, and has recently made the host shift to the oneseed hawthorn after its introduction.  Oneseed hawthorn fruits can become heavily infested with apple maggots, but this does not necessarily preclude invasivory!

These oneseed hawthorn fruits are ripe with apple maggots. Photo credit: S. Sim

Eating oneseed hawthorn

The USDA PLANTS database indicates that oneseed hawthorn fruits are not palatable to humans.  This may be so, but with a little preparation, it can become quite a tasty jelly!  When collecting oneseed hawthorn fruits, be careful of the thorny branches and keep the fruit and peduncle intact to prevent premature spoilage.  Unfortunately, it is currently mid-April and the fruits will not yet be ripe and ready for harvest for a few months, so check back in the future for a tutorial on how to make oneseed hawthorn jelly.

Both introduced into the United States, the domestic apple and oneseed hawthorn share a sunny spot in Vancouver, Washington. Photo credit: S. Sim



A self-proclaimed modern day nomad, I was born in the Philippines, grew up in southern California—lived all over really—and now I do research as a graduate student in Indiana and the Pacific Northwest. Professionally speaking, my current area of focus is speciation and ecological genetics and genomics, and a common theme in my various projects over the years is evolution in agricultural systems. As a recipient of a GLOBES—an interdisciplinary program funded by the National Science Foundation (NSF) through the Integrative Graduate Education, Research, and Traineeship grant (IGERT) —fellowship, I have received training which has better enabled me to view and ponder topics without my science hat on. I take great joy in eating, cooking, and experiencing nature through various activities. I love to travel and anticipate many local and international invasivore field trips! Though my research interests do not directly involve the study of invasive species, I have had my fair share of negative encounters with environmentally noxious organisms in the midst of doing field research. I carry around a machete with which to combat my gnarly “Himalayan” foes, and my machete and I have raised more than a few eyebrows. Apart from my personal vendetta against these deliciously juicy pests, I feel that there are great advantages to linking our awareness of the natural world to our culture, and Invasivore is an avenue to do just that. I feel that an increase in general knowledge of invasive species will be of great benefit to the field of invasive species and conservation biology. Knowledge and awareness will lead to action, and action will lead to results!

One thought on “Species profile: Oneseed hawthorn

  • February 10, 2015 at 2:53 pm

    Would love to have the jelly recipe if you can find one!


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