August Heat Wave: Mockernut Hickory (Carya tomentosa)

 

A mockernut hickory (Carya tomentosa) shows signs of suffering from the summer heat wave.

It grows on the grassy slope near Cline Hall, in full sun, near prominent sidewalk intersections. This is the most open area of the arboretum, with plenty of room for more plantings. The current residents of the slope do not compete for sun light, as there is no short supply. However, at this time of year, the trees and shrubs (and non-native grass) would prefer more water.

The mockernut, with its orangish-brown leaves, is pictured center. Directly behind it, there are two hawthorns that are showing signs of distress as well. By contrast, the largest trees in the picture have green crowns: pictured from left to right we see an aged white oak (Quercus alba), a mature overcup oak (Quercus lyrata), and a very tall loblolly pine (Pinus taeda).

The leaves of the mockernut aren't completely brown at this time. We see some green and some yellow as well.

Brown, crispy leaves of the mockernut hickory, pictured August 26, 2023

And can you see the large fruits hidden among the leaves?

The mockernut has prematurely dropped a bucketful of fruit. In this photo only a small collection of the total fruits, which litter the ground, is displayed. In 2020, ripening fruits were still attached to this individual in the middle of November; you can see the blog post here.

This twig looks healthy enough. Since the irrigation system is currently operating, we will do our best to keep this individual from drying out much more. Although, fingers crossed, hopefully the temperatures will stay below 100℉.

Mockernut Hickory (Carya tomentosa)

 

In mid-November, our mockernut hickory has lost nearly all of its leaves, giving us a good look at its growth habit. We do not have an exact age on this specimen, but we know it's less than 20 years old. It's still a small tree, not taking up much space on the grassy slope north of Cline Hall. From this angle, the mockernut has a straight trunk.

From another angle, we see a distinct lean in the trunk. At this age, the trunk lacks the flexibility necessary for an attempt to correct this lean with stakes, but perhaps in time, as the tree grows up and out, it will correct itself.

With the leaves gone, we can see large, globose fruits attached to slender, ascending branches.

Autumn leaves and ripening fruits of the mockernut hickory were photographed in November 2020.

 

Tree of the Week: Mockernut Hickory (Carya tomentosa)

Back in June, fruits were spotted on one of the mockernut hickories. You can read that post here. Once the fruits were noticed, the waiting game began―how long will it take for them to ripen? Now, in late October, mockernut hickory fruits have lost their greenness.

The dark brown husk is thick and large, measuring 2 inches in length. The nut is light-brown and round.

This nut measures approximately 1½ inches across. Nuts are said to be edible but difficult to crack. For suggestions on how to crack a difficult nut, please see the discussion on the nutmeg hickory fruit, found here.

Immature Fruit

 

We are keeping an eye on the mockernut hickory fruits, waiting for them to ripen. It's mid-August and we are looking at very large, round fruits. They are still green. You can read more about this individual tree on a previous post, found here.

 

Tree of the Week: Mockernut Hickory (Carya tomentosa)

Our tree of the week is a volunteer mockernut hickory (Carya tomentosa). All photos below were snapped on June 7th, 2020.

This mockernut grows in full sun on a grassy slope north of Cline Hall. An exact age isn't found in the catalogue; however, we know that it has been in this spot since at least 2008. We also know that it germinated on the grounds of the arboretum and was subsequently dug up and transplanted to this location. Its parent was an on-site native tree that has since departed.

Getting up close, we see fuzzy twigs and petioles, which help us identify the mockernut.

If the month of June brings you into close contact with a mockernut,  you might spy large, rounded fruits.

Fruits appear at twig apices, hidden by the compound leaves.

A small branch was snipped for inspection.

These fruits are immature, but already quite large. Mockernut fruits ripen in the fall.

Twigs are unmistakably fuzzy! Also, note the lines across the rounded fruits.

Mockernut leaves are long. From the branch we snipped, the largest leaf measured more than a foot in length.

Here we have seven yellow-green leaflets. Note the pointed tips and size variation in leaflets.

Underneath, leaflets are pale and fuzzy.

Zooming in on the leaflets we see a fine serration. Other individual mockernuts might have coarsely serrated leaflet margins.

You can see pictures of fresh new leaves here.

For more information about this species consult the following online sources:

United States Department of Agriculture
Fire Effects Information System (US Forest Service)

New Leaves of the Mockernut Hickory (Carya tomentosa)

The mockernut hickory (Carya tomentosa) has very large end buds. This end bud is at minimum an inch in length. The new leaves are still hidden.

This end bud has started to open: the velvety outer layer is peeling back.

The young, furry, compound leaves are revealed.

Autumn Update

This is an early-autumn view of the arboretum. The photo was taken about two months ago, on September 20, 2017. The grass is green; the trees, for the most part, have green leaves; and the crown of the sweet gum is starting to turn red.

From September to November, the colors have changed. This photo is from last weekend, taken on November 11, 2017. The grass is going dormant, losing its greenness. Leaves of Magnolia grandiflora and Quercus texana remain obstinately green, while the little mockernut hickory has lost all of its leaves. The crown of the sweet gum tree is really red now! And we have an extra splotch of color: the crown of the Carolina ash, which is peeking out from behind the magnolia, has turned yellow-orange.

Fall foliage of Sassafras albidum

Pictured from left to right: Acer rubrum, Sassafras albidum, Liquidambar styraciflua, and Fraxinus caroliniana.

Carya tomentosa