Coral Bean (Erythrina herbacea)

There are two coral bean (Erythrina herbacea) plantings in the arboretum. One is located on the north side of the Fitness Center, growing unfortunately in the shade of a hickory and an irrepressible & ever-spreading Chickasaw plum (Prunus angustifolia). The other coral bean has a more advantageous spot at the southwest corner of Mickle Hall. The latter plant has a flower stalk this week.

 

The flower stalk demands attention as it protrudes from the greenery of the coral bean, but the fresh spring-time growth of the nearby French mulberry and toothache tree conceal the bright red flower. 

 

Keep an eye on this flower stalk if you have an interest in collecting the pretty 'beans' that are expected to develop here. In the past, your arboretum curator has had exactly zero luck in germinating the seeds, so please feel free to collect them when they are ready. Good luck! Just be a bit careful, many parts of the plant contain poisonous compounds.

 

March Blooms in the Arboretum

Spring doesn't officially begin until the vernal equinox, which is still about two weeks away. But the weather, the animals, and the plants have decided that, for us in Shreveport, the season has arrived in advance of its astronomical formalities. 

Glorious flowering from our Mexican plums (Prunus mexicana) this week.

 

At this time, the flowers have a powerful, distinct, and not altogether pleasant aroma.  Nature's a funny thing.

Here we have a post from March 2019 featuring the same delightful Mexican plum blossoms. And a post from this time last year showing our efforts to transplant some new Mexican plums. Leafing-out season will tell us if that was successful.

Elsewhere in the arboretum, you can find flowers of the paw paw (Asimina triloba). These are less-showy. You will need to go looking for these along the drainage channel that runs north to south through the arboretum.

The juxtaposition of these deep crimson-purple bells alongside the green bells is unforgettable.

We attempted some cross-pollination. Good luck, little tree.

See our post from last summer on planting new paw paw and a similar springtime post from 2022 that features paw paw flowers.

Tree of the Week: Flowering Magnolia 'Little Gem' (Magnolia grandiflora)

It's magnolia season in the south. In the arboretum you can find fragrant flowers of both sweetbay magnolia (Magnolia virginiana) and flowering magnolia (Magnolia grandiflora). Our big-leaf magnolias (M. macrophylla) are not yet producing flowers.

Driving around Shreveport and Bossier City, we primarily see examples of the flowering magnolia. In the older neighborhoods, it's apparent that there was once a popular movement to plant them. As a result, there are hundreds of mature examples of this species right here in town. You might notice an enormous magnolia filling out the entire front yard of a house. It's hard to say what cultivars were used, since many were available even seventy years ago. One major change has occurred: a steep decline in the number of full-size cultivars being planted. Large flowering magnolias have fallen out of favor, with homeowners and commercial properties now giving preference to dwarf varieties. One such cultivar, 'Little Gem', is a particular favorite.

There are two 'Little Gem' magnolias in the arboretum collection. In 2000, two trees were donated to the college. Both reside outside of the arboretum proper. They are located near Crumley Gardens, between Crumley and Rotary Hall. One such tree is pictured below.

This 'Little Gem' magnolia was donated to the college in 2000. It grows in full sun in the middle of the grassy lawn between Crumley Gardens and Rotary Hall. After more than 20 years of growth, it is a little over 10 feet tall.

Flowers are creamy white and very fragrant. Leaves have an elliptic shape and come to a point. Leaves are shiny and emerald green on the upper surface, and underneath they are covered in soft, rust-colored fibers. Note: The flower, in this photo and the following photo, has taken on a bronze color due to several hours having elapsed since it was cut.

Compared to flowers you might find in a residential garden, the 'Little Gem' flower is large. This one measures nearly 7 inches across.

But compared to the full-size flowering magnolia cultivars, 'Little Gem' flowers and leaves are significantly smaller, and the leaves in particular have a different shape. Some sources claim that the 'Little Gem' carries hints of lemon in their scent.

Pictured left, we see the traditional Magnolia grandiflora. This is the flower you'll find on really big trees in older neighborhoods. On the right, we see the smaller 'Little Gem' cultivar; this is the flower you see in new development, such as parking lots around businesses constructed within the past 25 years.

 

 

Tree of the Week: Tulip Poplar (Liriodendron tulipifera)

This week we are celebrating the tulip poplar (Liriodendron tulipifera). This celebration is wholly due to Dr. Katie Bearden, whose eagle eye caught a glimpse of orange on high. This led to the discovery that a tulip poplar was blooming. Quite a find, considering that these flowers are located far above eye level and largely obscured by big, floppy leaves.

Tulip poplars are not native to northwest Louisiana, so it's unlikely that you would observe one in the wilds of Caddo, Bossier, DeSoto, or Webster parishes. However, tulip poplars grow natively in other areas of Louisiana and the southeastern United States. 

 If you visit the Centenary College campus, you can view five individual tulip poplars. All reside outside of the arboretum proper. Two are located between the arboretum and the cafeteria, and there are three between Crumley Gardens and Rotary Hall. Information on the source and age of these specimens is unavailable; we cannot say how old they were when they were planted, but we do know that they were planted in the late '90s. Today, all five trees are very tall, with no lower branches, and appear healthy.

 

Dr. Bearden first noticed the tulip poplar near the cafeteria. As noted above, the orange flower caught her eye. Since it was far out of reach, she enlisted the services of Eddie Walker, Chief of Public Safety, who used a drone to capture images of the flowers. The light orange flowers only just stand out against the green foliage.

Chief Walker's expertise operating a drone made it possible for us to see the flowers up close. Do you see a resemblance to our flowering magnolia? Tulip poplar and flowering magnolia are in the same family, Magnoliaceae.

In the hope of finding a flower within arm's reach, we examined the four other tulip poplars for a candidate. One tree in particular was thoroughly examined with the aid of a step ladder. All photos below are of a single tulip poplar, located near Crumley Gardens.

Our tree of the week is pictured center. It's a tall, narrow tree, whose form resembles that of our eastern cottonwood (Populus deltoides), and like the eastern cottonwood, tulip poplars are known to be fast-growing trees. Based on the height of the young woman pictured, this tree is more than forty feet tall. Champion specimens may reach heights in excess of 160 feet.

 

The tulip poplars on campus have straight trunks, and all lower limbs are absent, making leaves and flowers out of reach.

Using a step ladder to examine the lowest branches, we could only find remaining cones, vestiges of past glories.

 

Plenty of leaves were willing to be photographed. What a peculiar shape! Does it resemble a duck's foot with extra toes?

 

A branchlet was snipped for closer examination. Unfortunately there isn't a flower located at the twig apex.

 

Leaf stalks alternate along the twig.

Tulip Poplar Twig with Leaves

 

Large, boxy leaves are attached to long leaf stalks. Leaf and leafstalk together measure approximately one foot in length.

Tulip poplar leaves are symmetrically lobed. The leaf tip is inverted, or "notched". Leaf margins are smooth.

Underneath, leaves are pale green.

The tiny white dots are aphids. These were found on all the leaves that were closely examined. This level of infestation does not appear to be doing any harm to the tree.

 

In the photo above, the leaf appears particularly shiny and it feels sticky. According to Joe Boggs from Ohio State University's Buckeye Yard & Garden onLine, the stickiness is a byproduct of the aphids feeding on the tree. The "honeydew" attracts other insects and mold, which could harm the tree.

 

The gray trunk bark is rough and furrowed.

 

In a few spots we see the ridges crossed into a diamond pattern.

 

 

Grass was removed from around the base of the trunk so that we could get a good look at the root structure and also to keep the weed-eaters away from the bark. We will use mulch to replace the grass.

 

A few surface roots were identified in the grass, but nothing problematic for lawn maintenance.

 

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

Louisiana Plant Identification and Interactive Virtual Tours (LSU AgCenter) 

Buckeye Yard & Garden onLine (The Ohio State University) 

NC State Extension 

US Forest Service

What's in Bloom?

During the long, bright, hot, dry days of summer splendid orange flowers can be found throughout Louisiana, blooming under the harshest conditions, unfurling like trumpets sounding out through the green. Trumpet creeper vine (Campsis radicans) flourishes in the arboretum. It grows as a volunteer and steadily tries to invade and conquer new territory.

These tropical delights are known to cause skin irritation for some, so pluck and handle with care!

Pictured above, trumpet creeper vine (Campsis radicans) blooms along the red brick retaining wall between Hamilton Hall and Mickle Hall. The above photographs were taken during June 2020.

What's in Bloom?

Magnolia grandiflora has been flowering for over a month!

Magnolia flowers were enjoyed throughout the month of May, and now toward the middle of June the fragrant beauties continue to delight.

June is also the right time for elderberry flowers (Sambucus canadensis). You can find several plants in the upper pond, where the ground stays damp. These are all volunteers. In the photo above, elderberry is pictured with a water tupelo (Nyssa aquatica) and a slender Magnolia grandiflora. The Magnolia is also a volunteer.

Golden cannas (Canna flaccida) are nearly finished for the season. They like wet soil, too. You can find them on the west side of the upper pond.

Red Buckeye (Aesculus pavia)

Having a look from the long white wooden bridge, we see the upper pond thick with irises, sensitive fern, golden canna, and elderberry. Can you see the flecks of red in the background, beyond the pond? The red buckeyes are still blooming (April 5, 2020).

These large red buckeyes grow up hill from the pond; however, a couple younger specimen grow at the pond's edge. This species does well under a variety of conditions.

Pictured above, three little red buckeyes grow alongside a few yuccas under a very large, old loblolly pine (Pinus taeda). Despite their short stature, these little buckeyes are more than 20 years old!

The little trees, and more noticeably the flowers themselves, bend away from the shade, toward the sunlight.

Aesculus pavia flowers

Sweet-shrub (Calycanthus floridus)

Looking back through the arboretum blog, the sweet-shrub flowers at different times. In 2017, it flowered in April. In 2018, it flowered in May. Now, here we are in 2020, and our sweet-shrub is flowering in the middle of March!

The sweet-shrub is flowering! The photos below were taken March 21, 2020.

A seed pod remains attached to the shrub. This particular shrub does not typically produce many fruits; this is a rare find.

'Mt. Airy', Dwarf Witch-alder (Fothergilla major)

The new dwarf witch-alder is flowering! These white pom-pom flowers can be found by the Fitness Center.

Red Buckeye (Aesculus pavia)

Red buckeyes are flowering in the arboretum! The arboretum's original red buckeye plants are pictured above. They can be found growing in the shade of a lobolly pine and a water oak. These buckeyes are doing very well here, producing numerous large flowers, and this past fall they produced an impressive number of seeds. You can read about the successful germination project here.

Mid-March Spring Time Flowers

Puffs of white flowers cover the slender branches of the laurel cherry (Prunus caroliniana).

Wild geranium (Geranium maculatum) flowers are light pink and low to the ground. They are growing well with blue phlox, Christmas fern, and a young red buckeye.

Walking through campus you will see that some azaleas are already in full swing. Our yellow-flowered azalea shrubs (Rhododendron austrinum) are preparing for a dazzling display this coming week. They are called 'yellow-flowered'; however, in the ground of the arboretum, they are 'orange-flowered' and produce a delightful aroma. Don't miss it!