Scarlet Buckeye (Aesculus splendens)

The arboretum's only scarlet buckeye (Aesculus splendens) appears to be in its death throws. Leaves are absent and its limbs show evidence of decay, with patches of peeling bark. This tree was previously covered in a blogpost from 2021, and even earlier in a blogpost from 2018, alongside its old friend the peppervine (Ampelopsis arborea). Careful examination reveals some signs of life, but the outlook is grim.

This placard has weathered more than a few seasons. Our scarlet buckeye is, at minimum, 37 years old. It was purchased in 1988, from Woodlanders Nursery (Aiken, South Carolina).

 

You can find this tree on your right as you walk from the Fitness Center towards the Hargrove Bandshell.

 

We can see all the branches―they aren't concealed by leaves.

And up close the branches do not look good. Peeling bark opens the tree to attacks by insects and fungi, and it indicates internal deficiencies within the tree's health that make these problems more deadly.

 

A will to live is still present. Unfortunately, this tiny leaf is at the tip of a branch that already shows significant decay.

The trunk does not have any peeling bark.

And looking closely at the trunk, two green buds were found. This is one. Do you see it?

Zooming in on the trunk, we see new green growth.

 

This is the second green bud found on the trunk. Perhaps more will appear soon.

 

Although the prognosis is not good, the arboretum isn't a place to rush and cut a tree down―we're not in a hurry to determine the next step. Let's give the specimen a reprieve, and see what happens in the coming weeks.

Tree of the Week: Scarlet Buckeye (Aesculus sp.)

Most of the buckeyes in the arboretum are what we call 'red buckeyes.' In some of the older literature from the first half of the 20th century, you will also find the names 'scarlet buckeye' and even 'flame buckeye' used to refer to this plant.

 There is one specimen, however, who is a bit different. We've covered this tree in a previous post. It can be found just up the path near the small parking lot between the Student Union Building and Hamilton Hall.

We currently have it tagged as Scarlet Buckeye under Aesculus splendens. Due to the current taxonomic situation, this is as good as anything else we might use, although unfortunately not definitive.

 Is it a different subspecies? Or perhaps just a local variation of little consequence? This is very hard to say because today people are not much interested in our native buckeyes. To find some clues, let's dig into the literature. 

Correspondance between Charles Sprague Sargent (1841-1927; a Harvard botanist who operated the Arnold Arboretum) and Reginald Wodehouse Somers Cocks (1863-1926; professor of botany at LSU and Tulane) contained in the Journal of the Arnold Arboretum (volume 46, 1965) contains references to Aesculus pavia, Aesculus splendens, Aesculus discolor var. mollis. These scientists of the early 20th century did not consider these to be synonyms; they used those names to describe different buckeyes growing in Louisiana and the surrounding states. Today, all of this has been collapsed into Aesculus pavia.

The fruits of the scarlet buckeye and red buckeye differ appreciably. The former is bumpy or warty, while the latter lacks those noticeable bumps. Below, we have pictures of the scarlet buckeye. For comparison, you can find pictures of the red buckeye fruits here and here.

This fruit capsule hangs from the scarlet buckeye, photographed today, October 17, 2021. Note the black dots, which mark the bumpy texture. Only two capsules were seen hanging from this tree. Sections of another capsule were found in the leaf litter. All three capsules have bumps marked with black dots.

Seen from below with proper lighting, the extra texture on these fruits is quite distinctive.

In the arboretum, our red buckeyes produce large numbers of fruits. For instance, two years ago we had a large crop, which you can read about here, and this year, we are seeing the same red buckeye trees full of fruit capsules, some of which have started to split. By contrast, our scarlet buckeye rarely produces fruit.

Are these differences a subspecies variation or a result of competition? The scarlet buckeye has a peppervine close at hand, which may be stealing its resources. We chop back the peppervine every couple of years, just to make sure the scarlet buckeye isn't overwhelmed. The vine always bounces back quickly.

As you can see in this photo, the peppervine (Ampelopsis arborea) has thoroughly attached itself to our buckeye. We allow this, although we stipulate a pruning regimen.

Another complication is its flowers, seen here. Yellow flowers are characteristic of the Ohio buckeye (Aesculus glabra.) Maybe we have a mutation, a hybrid, or an undescribed subspecies. Let's keep an eye on this specimen.
 

 

Tree of the Week: Scarlet Buckeye (Aesculus splendens) [& bonus Peppervine {Ampelopsis arborea}]

There is one scarlet buckeye (Aesculus splendens) in the arboretum collection. It is a small ornamental tree, but don't let its diminutive size fool you. It's older than most of our undergraduates. In 1988, this specimen was purchased from Woodlanders Nursery (Aiken, SC), making the tree more than 30 years old. One reasonable explanation for its small size would be environmental competition. Since 1996, another native plant, peppervine (Ampelopsis arborea), has been allowed to grow with the buckeye. This means that the two species are in competition for sunlight, water and nutrients. The vine is terribly aggressive; it must be routinely cut back to give the buckeye room to grow.  

The scarlet buckeye is pictured center. Peppervine is growing with it, using the branches of the buckeye as a trellis. This photo was snapped just as a cloud passed overhead.

The little tree and its peppervine provide shade along the concrete and gravel sidewalks.

The light-colored buckeye trunk is partially obscured by the brown, ropy vines. A large loblolly (Pinus taeda) is pictured directly behind the buckeye.

The specimen was originally described as 'the tree form of our red buckeye', and it does indeed have a well-defined single trunk, as compared with the multi-trunk form of the red buckeyes (Aesculus pavia).

The scarlet buckeye has light gray bark.

Scarlet buckeye branch

Leaves appear in pairs, opposite from one another along the twig.

Scarlet buckeyes have large, palmately compound leaves. In this picture we have one large leaf composed of six dark-green leaflets. Leaf and petiole together measure almost a foot in length.

Leaflets vary in size, measuring less than 6 inches.

Leaflets have finely serrated margins.

Underneath, leaflets are a lighter shade of green.

They are also a little fuzzy underneath.

This week we see peppervine fruits hanging from the buckeye branches. The fruits turn from white to red to black.

Like the scarlet buckeye, peppervine has dark-green compound leaves that might remind one of parsley fronds.

Peppervine has twice compound leaves. This particular leaf has approximately 21 leaflets.

Leaf and petiole together measure less than 7 inches.

Peppervine leaflets are dark-green with toothed margins. The small, globular fruits turn black upon ripening; they are perfectly edible but most will find their flavor less than satisfying; The fruit is slightly sweet, a little peppery, and contains several seeds.

You can find more pictures of the arboretum's peppervines here.

A picture of the scarlet buckeye flower can be found here.

Aesculus splendens