August Heat Wave: Blackjack Oak (Quercus marilandica)

At the beginning of fall term, leaves litter the ground in the arboretum. Some trees look vibrant, while others look suspiciously withered, like the end might be near. More than a month of dry, hot weather has resulted in alarmingly crispy leaves in our native trees. Shouldn't our Louisiana natives be able to withstand an August heatwave? Perhaps, but the trees in the arboretum catalogue have grown up in a human-dependent environment, with a sprinkler system and routine lawn maintenance, so we cannot make generalizations based on the well-fare of the individuals on display in the Centenary arboretum. But, it's sad to see! 

A blackjack oak (Quercus marilandica), located on the grassy slope near Cline Hall, is one such pitiful specimen. As remarked on previous blog posts (here and here), this is a tree with a special history: it resprouted after vandals broke the trunk at its base.

The blackjack oak is pictured center. It's a small tree, growing in full sun. Typically during the summer months this grassy slope is irrigated. Unfortunately for these individuals, the irrigation system has not been working properly during the past several weeks, when the irrigation was needed most.

Leaves of the blackjack oak are turning brown. This it not 'fall coloration'! We are three months too early for that. This tree has been featured on the blog for its remarkable autumnal color—check out the photos here.

During this stressful period, the tree holds fast to its developing acorns!

2022 Acorn Watch: Blackjack Oak (Quercus marilandica)

 

This week in the arboretum, have a look at our diminutive blackjack oak (Quercus marilandica). Its leaves are changing colors, and you can examine its ripening acorns. The acorns may very well drop in the next few days.

You can find this blackjack oak on the grassy slope near Cline Hall. It grows by itself, in full sun, and it is clearly labeled with a sign.

 

Although it is more than 25 years old, this tree remains relatively small. Approximately two decades ago, vandals broke the trunk off down to the ground. The tree defiantly re-sprouted and was then replanted in a different location, and despite that difficult life history it appears to be in good health.

 

However, looking at the above photograph, on the right side of the trunk, we see that the base is malformed. Even though this tree resprouted, it sustained a permanent injury from the act of vandalism. It may also be the case that this tree is stunted. Today, it stands at a height of 7 feet, 8 inches.

 

It's short, but still producing acorns! And since the tree is small, we can easily observe the little gems. This week they are turning brown.

Ripening blackjack oak acorn, pictured October 30, 2022

 

You can see an old fall foliage picture of this individual here.

For additional information about this individual and for spring time photos, click here.

 

2022 Acorn Watch: Blackjack Oak (Quercus marilandica)

 

Back in July, there were several clusters of immature acorns on the lower limbs of the arboretum's senior blackjack oak (Quercus marilandica). Now that it's September, we only see a few scattered immature acorns on the lower branches. Below, we have three pictures illustrating the change.

On July 3rd, we saw a cluster of five immature acorns. This is only one of several clusters that were easy to examine while standing on the ground. You can find more photographs on the July blog post, found here.

In the middle of September, while standing on the ground, we see a few single acorns and only a couple of small clusters. In this photograph, there are two nicely developing acorns and one tiny, perhaps non-developing, acorn. A ladder was not used to investigate further up the tree.

In this photo, we have one developing acorn and a small non-developing acorn. While it's unfortunate that we do not have a better selection to examine, it's nice that there are some developing acorns to study. And these are neat little fruits! Can you see the orange fuzziness on the green acorn? Hopefully the ones that remain will continue to develop uninterrupted so that we can photograph the final product.

Tree of the Week: Blackjack Oak (Quercus marilandica)

 As of June 30, 2022, the US Drought Monitor has identified a 'moderate drought' in our area, specifically the southern half of Caddo Parish. Some of us had noticed this weeks in advance; rain has been scarce and temperatures have been in the upper 90s. Fortunately, we received a slow, steady rain on July 2nd, but the same hot, dry weather has returned and is expected to be with us for the foreseeable future. 

 So, when our environment is experiencing a 'moderate drought', what happens to acorn development? Will immature fruits drop, or will the fruits fully develop under drought conditions? As of right now, immature acorns are abundant in the arboretum. Two weeks ago, we noted that there are developing acorns on the arboretum's young post oak (Quercus stellata). This week we have a few pictures of acorns from one of our blackjack oaks (Quercus marilandica). Over the next several weeks, we will look at the developing acorns on the overcup, Arkansas, burr and Durand oaks.

 

Our tree of the week is at minimum 35 years old. In 1988, it was purchased from Woodlanders nursery, located in Aiken, South Carolina, and planted the same year. We have previously discussed this individual on the blog, once for its bright orange fall foliage, and once for the same attribute as found in the below pictures, i.e., immature acorns.

 

Small, immature acorns appear in clusters toward the tips of the branches (July 3, 2022).

 

Blackjack oak acorns, photographed July 3, 2022

 

We see so many little acorns, but what will happen to these acorns over the next couple of months? In June 2020, we noted the same event―numerous acorns―but failed to follow up during the autumn of that year. This year we are making a point to follow acorn development, primarily with an end to collecting post oak acorns for a germination project. If they make it, we might also pot a few blackjack acorns!

 

 

 

 

 

Tree of the Week: Blackjack Oak (Quercus marilandica)

The dark, rough and bumpy trunk pictured above belongs to a blackjack oak (Quercus marilandica). This specimen was purchased in 1988, from Woodlanders Nursery, located in Aiken, South Carolina. This individual caught our eye this week.

In late June, we see numerous immature acorns.

We must remember to check on these in the fall, to see how big they get. Last year we discussed the beautiful fall foliage of this specimen, but we didn't record any notes on acorns. You can find that old post here.

The photos above were taken on June 27, 2020.

Fall Foliage: Blackjack Oak (Quercus marilandica)

There are two blackjack oaks (Quercus marilandica) in the arboretum collection, and they turn two different colors in the fall. Our oldest specimen turns bright orange. You can read about it here. The younger of the two turns deep red; it's pictured below. 

This small tree is over 20 years old. You can learn its history (along with an explanation for its short stature) from a previous blog post, found here. Unlike the other blackjack oak, this one turns unmistakably red. Both trees were purchased from Woodlanders Nursery (Aiken, SC).

Fall Foliage: Blackjack Oak (Quercus marilandica)

For the past two weeks our older blackjack oak (Quercus marilandica) has taken on a cloak of orange. All photos below are of a single specimen.

In October 1988, Professor Ed Leuck purchased this blackjack oak from Woodlanders Nursery (Aiken, SC), making this individual more than 30 years old. The black trunk is straight, but most of its limbs are concentrated on the south side of the trunk. This is most likely due to competition from a close neighbor, an overcup oak (Quercus lyrata).

Our blackjack oak grows in full sun at the top of a gradual slope.

Its leaves have been orange for a couple of weeks.

The leaves of another neighbor, a longleaf pine (Pinus palustris), hang on the branches of the blackjack oak.

Fall foliage of Quercus marilandica against a blue sky

Leaves vary in color, but the most stunning leaves are glossy orange.

Leaves and buds alternate along the branch.

Leaves also vary in shape and size. Typically, leaves have 3 shallow lobes. This leaf measures approximately 4½ inches long.

Here we have an unusual asymmetrical shape. This leaf measures more than 6 inches in length.

This leaf is even longer, measuring nearly 7 inches in length. It has the more typical 3-lobe shape.

Blackjack oak leaves are widest near the apex. This leaf measures more than 6 inches across.

This leaf is nearly 7 inches wide and resembles a stingray in shape.

Underneath, the autumnal coloration is subtle on some leaves.

These leaves are a little fuzzy underneath. Can you see the particles along the midrib?

Tree of the Week: Blackjack Oak (Quercus marilandica)

After a two-week-hiatus the 'tree of the week' feature returns. If you've been in the arboretum recently, you've probably been overwhelmed with new growth and rampant activity. Plants, animals, and people are all appreciating the change in season. This week we are focusing on an adolescent oak tree, a blackjack oak (Quercus marilandica). Its catkins caught our attention. This small, young blackjack oak is already participating in the pollen game, which has been going steady for the past several weeks, covering all creation with a fine yellow dust.

Our young blackjack oak looks good today, but it had a difficult beginning in the arboretum. This oak was purchased from Woodlanders Nursery (Aiken, South Carolina) in 1997, and it was planted in November of the same year. Initially, it was planted between Rotary Hall and Cline Hall, outside of the arboretum proper. A sordid act of vandalism broke the tree at the ground. Unusually for an oak, the tree vigorously resprouted and was subsequently transplanted to its current location, the grassy slope on the northside of Cline Hall.  

Of the two blackjack oaks in the collection, this one is the youngest, a little over 20 years old. It's growing in full sun, on a grassy slope with other young trees.

This blackjack oak has plenty of room to grow. In the background stands an aging white oak (Quercus alba).

Blackjack oaks have simple leaves with shallow lobes. The new leaves are thick, glossy, and green.

Underneath, the new leaves are smooth and light-green.

The twigs are covered in fine, light, golden particles. Leaves occur alternately along the twig.

This young tree caught our attention because of its grown-up activity. The male flowers are catkins that dangle from the new growth. These flowers have been releasing pollen into the vicinity over the past two weeks, and now, thankfully, they appear to be finished.

The golden catkins hang like ornaments. 

Catkins produced by this young tree measure up to 3.5 inches long.

Blackjack oaks have characteristic black, blocky bark.

You can see additional images of the arboretum's blackjack oaks here.

For more information about this species consult the following:
United States Department of Agriculture
Virginia Tech Dendrology
U.S. Forest Service
Louisiana Plant Identification and Interactive Virtual Tours (LSU AgCenter)

Autumn Update

There is a lot of autumnal color in the arboretum. Oaks, maples, witch-hazels, hickories and cypresses all have pretty leaves, but the leaves are dropping so fast! Soon the cold, wet winter weather will be here to stay.

Looking into the arboretum from the southwest corner of Mickle Hall: the trunk of an on-site-native post oak (Quercus stellata) is in the foreground, pictured on the right.

This beautiful yellow bush is a grouping of witch-hazels (Hamamelis virginiana).

Blackjack oak (Quercus marilandica)

Red leaves of the blackjack oak (Quercus marilandica)

The orange leaves of this red maple (Acer rubrum) are quickly falling.

This yellow-leaved tree is a nutmeg hickory (Carya myristiciformis).

Interestingly, our wild crabapple tree (Malus angustifolia) thinks it's a good time to flower, and the flowers are very aromatic.