Tree of the Week: the Mayhaws (Crataegus opaca and Crataegus aestivalis)

Over the past couple of weeks we have been studying the eastern red cedar (Juniperus virginiana). This attention has resulted in a decision to deal with the irksome cedar-apple-rust, whose galls are currently developing in the eastern red cedars. These galls are expected to 'open' soon, releasing their spores into the environment. Rather than targeting the galls themselves, which are housed in the inaccessible heights of the cedars, we decided to begin with a more manageable project: protecting the alternative hosts, and victims, of the rust.

The eastern and western mayhaws are susceptible to infection. These are small, early-blooming fruit trees that produce cranberry-like fruits. They are a southern gem. The best known way to protect the fruit tree is to spray the flower buds just before they open. Because the buds are currently developing, now is the time for action.

There are four mayhaws in the arboretum collection. Three western mayhaws (Crataegus opaca) are from Louisiana Forestry. They were acquired in 1994, and planted the following November, making them more than 20 years old. Our only eastern mayhaw (Crataegus aestivalis) was purchased from Woodlanders Nursery (Aiken, South Carolina) and planted along with the others. The four mayhaws dwell south of the long white wooden bridge, near the drainage channel that runs through the arboretum. The pictures below show that there has been some competition for sunlight; the crowns of the four trees have grown together.

The pictures below were taken on a cool cloudy January day.

We are looking toward the east, with the red bricks of Mickle Hall in the background. The eastern mayhaw is pictured center. Two western mayhaws are pictured to the left of the center tree, and one western mayhaw is pictured to the right. All three western mayhaws are leaning south, and one trunk is noticeably thicker than the other three.

Here we are looking north. The one mayhaw trunk is still noticeably thicker than the other three.

Two flowers were spotted on the branches, blooming ahead of season. This pretty white flower was found on the southern-most western mayhaw (C. opaca). As you can see, the flower appears in a cluster.

Most of the flower buds look like this. They aren't opening yet.

The buds are a rosy pink.

After researching cedar-apple-rust and comparing several options for treatment, Immunox was found to be the best option for protecting the mayhaws.

There are specific instructions for mayhaws on the Immunox bottle. For our sprayer, we mixed 2/3 fluid ounce of Immunox for each gallon. The instructions tell us that the best time to spray is when the buds are opening. Other recommendations advise a first spray during the "pink bud stage," which is the option we chose.

Precautions were taken to protect our skin from the fungicide solution, wearing rubber gloves, hats, and protective eye-wear.

The instructions state "apply to all parts of the tree to point of runoff", so we made sure to thoroughly spray the mayhaw branches.

This is the gray bark of the eastern mayhaw (C. aestivalis). Note the orange specks of new bark (see C. marshallii). The tree trunks were also thoroughly sprayed with the fungicide solution. 

You can see more photos of the arboretum's eastern mayhaw here. 

And you can find photos of the western mayhaw here. 

For more information about the mayhaws, consult the following links:
United States Department of Agriculture -- Western Mayhaw (Crataegus opaca)
United States Department of Agriculture -- Eastern Mayhaw (Crataegus aestivalis)
University of Florida IFAS Extension -- Eastern Mayhaw (C. aestivalis)
Temperate Climate Permaculture