Tree of the Week: Sweetbay Magnolia (Magnolia virginiana var. australis)

Thankfully the brutally hot weather has passed: high temperatures are now around 90℉. This past week, northwest Louisiana has received scattered rain showers, some of which have been heavy. Interestingly, the vegetation in the arboretum, especially the grass, has recovered quickly. The landscape is mostly green, especially since the mower has chopped up the majority of the fallen leaves. Unfortunately, there are lingering signs of the damage caused by the August heat wave. Below, we have pictures of one such case: an evergreen sweet bay magnolia with an alarming number of brown leaves.

Our tree of the week is an evergreen sweetbay magnolia (Magnolia virginiana var. australis). This tree was purchased and planted in 1997, making it at minimum 26 years old. It has grown happily in the arboretum and lived true to its 'evergreen' designation. You can read more about its history on an older blog post, found here.

At this time, the brown crown of the sweetbay is conspicuous in the mostly green, or yellow-green, landscape.

Approaching the sweetbay, we see brown leaves up above and green leaves at eye level.

Browned, withered twig of Magnolia virginiana var. australis, photographed September 23, 2023

Healthy twig of Magnolia virginiana var. australis, photographed September 23, 2023

Looking at the multi-stemmed base, we see plenty of green leaves. So, we know that this tree is very much alive, although we cannot say what kind of condition it is in. It will be interesting to see what happens to the upper parts of the trunks.

Tree of the Week: Sweetbay Magnolia (Magnolia virginiana), Coppice edition

 A year ago in September 2020, Hurricane Laura wrought some havoc in the arboretum. You can read the original post about that event here. The most noteworthy damage was to a pair of sweetbay magnolias, which suffered severe breakage to their trunks. Ultimately, we decided that the trees were a total loss and cut both away at ground level. The result, rather than the death of the trees, was coppicing.

After the weeks long cleanup operation that followed Hurricane Laura, two sweetbay magnolia stumps remained (September 2020).

Coppicing is an ancient practice for which only some species of trees are fit. To coppice a tree, you cut it down with only a few feet of stump remaining. This is typically done to harvest lumber, for firewood, or to make charcoal. Trees that are amenable to coppicing will not die but rather will send up new shoots. What's going on underground? Does the tree preserve its entire root network? Does it atrophy? We don't know. If you attempt this with most trees, the result will be a swift death for that specimen.

Regrowth from the stump (April 2021)

The following spring, the sweetbay magnolias unexpectedly began to sprout. We weren't sure how it would get along. You can read the previous post here.

In late fall, the two stumps are now obscured by new growth. The two trunks didn't produce the same number of shoots; the stump on the left produced significantly fewer shoots.

We see five or more shoots emerging from one stump (September 2021).

The other sweetbay magnolia produced more than 10 shoots, enshrouding the stump (September 2021).

What is to be done with all of this new growth? Ought we simply allow the sweetbay magnolias to develop unhindered, or ought we take an active role in shaping their futures? For the sake of increasing visibility in the arboretum, the decision was made to at least thin the new shoots. One stump was allowed to pursue the destiny of a shrub, while the other stump was cut back to a single leader. Of course, based on what we have already seen from these two magnolias, we expect that more shoots will appear.

 For one stump, the decision was made to encourage a single straight trunk; therefore, we removed all but the largest shoot (September 2021).

For the other stump, the shoots were thinned, but it will still maintain its current form as a shrub.

 

Tree of the Week: Sweetbay Magnolia (Magnolia virginiana)

Spring is the time of resurrection. This week in the arboretum, we have two trees that appear to have come back from the dead.

Last fall, Hurricane Laura sent a water oak limb crashing down onto two sweetbay magnolias (Magnolia virginiana). The damage was so extensive that we completely removed both crowns and sawed the trunks down to the ground. To all appearances, the stumps were lifeless. No visible activity was noted during the fall or winter months. This week, things changed. Fresh green shoots can be found on both stumps. 

Two sweetbay magnolia stumps can be found on the east side of the upper pond. These stumps are inconspicuous in the landscape.

Each stump has one shoot that is approximately a foot tall.

Smaller sprouts can be seen as well.

 

These weren't large trees, but both were over 30 years old. You can read about them and see more pictures on another blog post, found here.

The vigorous growth suggests a well-developed root system, but how many roots survived? Surely this little stem doesn't have the full advantage of a 30-year-old root system.

 

Who knows what the future holds for these sprouts, but, for now, the arboretum catalogue has been updated to state that these trees aren't dead, and they will be allowed to grow a full season.

Sweetbay Magnolia (Magnolia virginiana)

Two sweetbay magnolias (Magnolia virginiana) were recently removed from the arboretum catalogue. During Hurricane Laura, a falling oak limb landed on top of the two trees, not killing them, but significantly mangling them. One was bent to a near 90⁰ angle; the other lost most of its crown. For the time being, the stumps remain for your inspection.

The two white surfaces pictured above are sweetbay magnolia stumps. Before the storm, both trees appeared perfectly healthy. They were both approximately 35 years old. One tree was collected and planted in 1985, and the other was purchased from a nursery and planted in 1988. Exact ages are unknown, but they were nearly the same age. The two sawed-off stumps are interestingly dissimilar.

One of the two stumps is noticeably larger than the other. This is the larger one. It's nearly two feet across and perfectly smooth.

The tree rings are easy to see.

The other stump is smaller and marred.

The stump is a foot wide, and the damaged center is approximately three inches in length.

 

Hurricane Laura Damage: Upper Pond

In late August, during the Hurricane Laura weather event, the arboretum suffered a minor catastrophe in the upper pond. A large limb broke from the crown of a mature water oak (Quercus nigra), crushing beneath it several medium-sized trees. Such a mess resulted that it's difficult to discern from photographs what exactly took place.

All of the damage can be traced back to this mature water oak (Quercus nigra). At the top, the trunk divides into four large branches. One of these branches snapped off during the storm.

The branch fell towards the pond, landing on several medium-sized trees. It remained suspended on a bent sweetbay magnolia (Magnolia virginiana).

The weight of the oak branch bends the sweet bay magnolia over the gravel path.

One sweetbay magnolia is bent over the path, while a nearby sweetbay completely lost its crown.

After more than two weeks of clean-up, things are back to normal in the arboretum. Hurricane Laura changed the look of the upper pond. The old water oak lost a very big, mature limb, and two sweetbay magnolias had to be completely removed due to the excessive damaged they suffered. As a result, more light will now hit the vegetation growing in and around the wet area. 

Younger, smaller trees have been lying in wait for such a moment. Hundreds of redbay seedlings would love the opportunity to fill the gap left by the two sweetbays. A spindly big-leaf magnolia struggled for years in the shade, and a laurel-cherry, who happily grows in the shade, now has the extra sunlight to grow tall. Over the past decade, powdery thalia has all but disappeared in the upper pond due to the advancing shade created by maturing trees. Perhaps it will return. For now, the plan is to prevent each and every little redbay from growing in the upper pond, while at the same time encouraging the big-leaf magnolia, laurel-cherry, and thalia.

Upper Pond, September 2020

Upper Pond, September 2020

East side of Upper Pond, September 2020

Sweetbay Magnolia (Magnolia virginiana)

Sweetbay magnolia flowers are smaller, and therefore less visible, than the flowers of Magnolia grandiflora. You probably won't be able to see the flowers from a distance, but the sweetbay trees in the arboretum tend to produce an abundance of charming flowers.

Like M. grandiflora, M. virginiana flowers during the month of May in northwest Louisiana.

Springtime Flowers

The sweet bay magnolias (Magnolia virginiana) have been blooming for at least a week. Very fragrant! You can find these flowers at the southern edge of the arboretum, near the Fitness Center.

Magnolia virginiana var. australis

The evergreen sweetbay magnolia lives up to its name. The following three photos were taken over the course of 12 days in January. Despite the unusually cold and snowy weather, this variety of sweetbay hasn't lost its leaves. The five regular sweetbays are bare.

January 15, 2018

January 16, 2018

January 26, 2018

Tree of the Week: Evergreen Sweetbay Magnolia (Magnolia virginiana var. australis)

Yesterday in Caddo parish we had sunny, 60-degree-weather. It was a pleasant day for taking pictures of our tree of the week, the evergreen sweetbay magnolia (Magnolia virginiana var. australis). This tree is very much like any other sweetbay, but it keeps its leaves during the winter months. So, in the middle of January, the dark green leaves remain on the tree.

There are two evergreen sweetbays in the arboretum collection. Ed Leuck acquired these two trees from John Mayronne at a meeting of the Louisiana Native Plant Society. The meeting was held January 26, 1997, and the trees were planted the following November, making them over 20 years old. The photos below show that one of the two trees is significantly shorter than the other. The shorter tree is growing on the north side of its companion, which means that it gets less sun. This explains some of the difference in height. But another explanation is that the shorter tree was crushed by a falling Pinus taeda on April Fool's Day in 2000. Amazingly, the sweetbay recovered, and both trees are in good condition today.

After such a beautiful day, the weather quickly changed. The rain started in the evening and transitioned from sleet to snow by midnight. Waking up this morning, we had a Louisiana-style winter wonderland. The rare event necessitated a photography expedition. So, we also have a few pictures of the evergreen sweetbays in the snow.

The grass isn't green anymore, and the old oak trees are looming overhead without any leaves on their branches. Meanwhile, this variety of sweetbay magnolia remains green, as if it's still summer.

There is a narrow drainage channel, or "creek", that runs west to east through the arboretum. One sweetbay was planted on the north side of the creek, the other on the south side. Although the two trees are the same age, one tree is clearly shorter than the other, suggesting a competition for resources. In this photo, we are looking eastward.

The tree on the north side of the creek has a single trunk, while the other tree has a multi-trunk form.

The multi-trunk form is common for sweetbays. Surface roots aren't a problem with these two trees.

The elliptic leaves are dark green in the middle of January.

Sweetbay leaves are white underneath. On a sunny, windy day the leaves have a silvery appearance, making the tree identifiable from a distance.  

After a beautiful, sunny, 60-degree day, the weather rapidly turned cold. Approximately 2 inches of snow fell during the night. 

The weather was cold enough to allow the snow to accumulate.

Snow remained on the evergreen leaves during the following day.

For more information about this species consult the following:
LSU AgCenter
United States Department of Agriculture
Louisiana Plant Identification and Interactive Virtual Tours (LSU AgCenter)
University of Florida IFAS Extension
NC State Extension

What's in Bloom?

In the middle of May, the arboretum collection is displaying a variety of creamy white flowers. The oak-leaf hydrangea bushes (Hydrangea quercifolia) and sweetbay magnolias (Magnolia virginiana) have been in flower for several weeks now. You can't miss the hydrangeas, but you'll need to go looking for the sweetbay flowers. The flowering magnolias (Magnolia grandiflora) have been in bloom all over town, but the trees in the arboretum collection have just now started blooming. On the slopes of the arboretum the viburnums are producing clusters of white flowers, and in the wet areas along the drainage the lizard-tail flowers can be seen. The large leadplant bush (Amorpha paniculata) breaks with the color scheme, showing us its purple and orange flowers in a wild display of racemes.

Oak-leaf hydrangea (Hydrangea quercifolia) flower

Evergreen Sweetbay (Magnolia virginiana var. australis)

Flowering Magnolia (Magnolia grandiflora)

Ashe's viburnum (Viburnum ashei) is a large bush covered in white flowers, located near Mickle Hall.

Lizard-tail (Saururus cernuus) flower and leaves

There are several substantial patches of lizard-tail in the arboretum, along the main drainage that runs north to south.

The purple and orange flowers of the Amorpha paniculata bush add a dash of extra color to the arboretum this month. 

Amorpha paniculata racemes and leaves