Thornless Cockspur Hawthorns – Growing A Thornless Cockspur Hawthorne Tree

Thornless cockspur is a type of hawthorn (Crataegus monogyna) native to North America. It’s one of the most common types of hawthorns in cultivation today, but it isn’t very popular because it requires so much care and attention that many people don’t have the time or inclination to do it.

In fact, it’s not even known what causes thorns to grow on this species of hawthorn. There are theories that say there could be genetic factors involved, but no one really knows why some trees develop thorns while others don’t.

Some believe that the reason may be due to environmental conditions such as drought or high temperatures. But other than these environmental factors, there aren’t any specific reasons for why certain plants develop thorns.

It’s believed that thorns on thornless cockspur hawthorn trees are caused by two different types of insects: the fungus gnat (Ptychophora maculiventris) and the grasshopper moth (Mecynocephala pulex). These pests attack the leaves and shoots of thornless cockspur hawthorn trees when they feed on their sap.

While insects typically suck sap, these types of insects also inject a toxin into the plant as a defense mechanism. The injection of this toxin is what causes thorns to grow on the shoots of cockspur hawthorn trees.

Normally, cockspur hawthorns have smooth shoots without thorns, and they aren’t prickly to the touch at all. But when these two specific insects attack, the thorns can grow up to 2 inches long!

They aren’t solid like other types of thorns though. Instead, they’re more like quills. They aren’t hollow, but they easily pierce the skin. The tips are very sharp and filled with a toxin that can cause a lot of pain. While these types of trees rarely kill any animals, they do cause a lot of discomfort, which is why you don’t see them in many places today.

The good news is that these types of insects don’t typically like to live on hawthorn trees. They prefer to live on grasses and herbs instead.

So if you’re growing a thornless cockspur tree, you’re unlikely to have many problems.

Even so, it’s still important to check your tree for these types of insects every once in a while. The best way to do this is to look at the leaves, shoots and even the trunk of the tree.

These insects typically like to hide on the underside of the leaves, where they’re harder to spot. You may need a magnifying glass to get a good look. Look for small bugs that are brown or black in color. If you find any, take a sample into your local Cooperative Extension Office. They can tell you whether or not the insects are harmful to your tree.

If your tree is affected by these insects, there are a few things you can do to lessen the effects. First of all, try to avoid planting thornless cockspur trees in areas that are prone to drought.

Thornless Cockspur Hawthorns – Growing A Thornless Cockspur Hawthorn Tree |

It’s easier for these types of insects to attack the plant when it doesn’t have enough moisture. At the first sign of trouble, make sure you water your tree. You can also trim off any shoots or branches with infestations. This will slow the spread of the infestation. You can also apply pesticides, but be careful not to use too much. Too much pesticide can also be harmful to your tree, so only apply as much as is needed to get the job done.

Whether you have a thorny or thornless cockspur tree, it’s important to keep an eye on it. These beautiful trees can live for several decades when properly cared for.

With a little bit of attention and love, your tree will be healthy and thriving in no time!

Sources & references used in this article:

Disease and Insect Resistant Ornamental Plants: Crataegus (Hawthorn) by M Thurn, E Lamb, B Eshenaur – 2019 –

Suggested Tree Planting List for ALB Quarantine Zones and Surrounding Areas by E Redbud –

Arboretum Review: Small Trees by D Wyman – Arnoldia, 1962 – JSTOR

Contrasting Ohio nursery stock availability with community planting needs by LC Snyder – 1973 –

Recommended Tree Planting List for the ALB Quarantine Zone by TD Sydnor, S Subburayalu… – … & Urban Forestry. 36 (1): 47 …, 2010 –

Trees to Avoid Planting in the Midwest and Some Excellent Alternatives by S Areas – Notes, 2004 – Citeseer

Fitting trees and shrubs into the landscape by LG Jull –

Minnesota Tree Line: Shade Trees for Central Minnesota, no. 26, 1980 by MC Eisel – 1974 –



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