Big-Leaf Magnolia (Magnolia macrophylla)

Another germination project is underway. One of our big-leaf magnolias successfully produced fruit this year, so we have seeds to plant! Big-leaf magnolia (Magnolia macrophylla) is native to Louisiana, and it's a tree with a very interesting appearance, but perhaps too delicate for widespread plantings. 

The successfully reproductive big-leaf magnolia is pictured center. Its slight trunk is barely visible. We mainly see the large, floppy leaves extending from the tips of slender branches.  

Centenary alumnus Bonnie Bernard germinated this tree when she was a student in 2012; she or Dr. Leuck planted it in the arboretum the following year. That makes it 14 years old by the end of this year. We have seen flowers in previous years, but this is our first year to collect seeds. You can read more about it and see some older photos in this previous post.

The red, egg-shaped fruit was spied during the summer. (photo: 8/22/26) 

Approximately a month later, we now have fully visible seeds. The seeds were positively ejecting themselves from the cone ("bombs away!") when the branch was jostled for this photo.

The slender tree branches are flexible. A ladder wasn't needed to collect the fruit, but it was nice to have someone hold the leaves down so that the fruit could be snipped.

 

These orangish-red (cinnabar? vermilion?) seeds are ready for dispersal.

Magnolia macrophylla seeds collected September 2026

We collected 34 seeds, some of which are noticeably discolored. We aren't sure about the quality of the seeds collected―the dark spots and brownish coloration suggest that those seeds might be defective―but they will all be given a fair chance to germinate. 

Summer Trillium

Trilliums have a rarity and delicate beauty that grant them a wide following among botanical enthusiasts. The four most common species of trillium in Louisiana are T. texanum, T. recurvatum, T. ludovicianum, and T. gracile.

In the arboretum, we have patches marked for T. gracile and T. recurvatum. T. gracile was acquired first, in 1992. Professor Leuck's Plant Systematics class took a field trip down to the Kisatchie National Forest in Natchitoches Parish, and they brought back one T. gracile plant. It was planted in the arboretum, and over the years a patch of trillim developed. Two additional plantings were added to this patch, all thought to be T. gracile: in 1993, Will Cook donated two plants, and in 1994, the Plant Systematics class brought back two more plants from Kisatchie.

In 1994, Jack Price donated T. recurvatum, collected from Caddo Parish. Two years later, another plant from the grounds of the Veterans Affairs Hospital in Shreveport was added to the patch. In 1998, two pots of T. recurvatum origianlly collected from Ida, Louisiana, were then added to the same spot. Finally, in 2013, Professor Leuck donated his own private collection of T. recurvatum to the arboretum, adding them to same location.

Since we haven't closely examined these species on the blog, let's start today, as this week we noticed seeds from a patch marked T. gracile. Have you ever seen trillium seeds? Few people have.

All photos below are of a single patch of trillium, currently labeled as T. gracile. This blog post is meant as a start for close examination of the arboretum's trillium species. It has been three decades since the first planting of trillim into the arboretum, and classification criteria change over time. Plants get moved around, too; a volunteer trillium will pop up in an inhospitable location and need to be relocated to a safe spot. It could very well be the case that we have mixed patches of trillium. Perhaps T. gracile and T. recurvatum have even hybridized! So, we need to see what the trillium specialists have been studying and how these folks have been dividing up the various species. All photos below are from July 2023. These are summer photos and consequently the leaves (bracts) aren't in their best condition.

Here we see one individual trillium. It has three green, floppy leaves elevated off the ground by a stalk. These aren't regular leaves; these are called bracts, and they are part of the trillium reproductive structure. Despite the hot-hot July weather, these bracts are still in fairly good condition. We see that they are mottled and are close together. The bracts surround a ripening seed pod. This individual is showing definite characteristics of T. gracile.

Zooming in on the ripening seed pod, we see that the sepals are partially shielding the pod. Also, note how the seed pod appears to sit on top of the bracts. There isn't a stem separating the seed pod from the bracts. For classification purposes, this type of trillium is called 'sessile.' Both T. gracile and T. recurvatum are sessile.

This is another individual, in the same patch of trillium, and it has a slightly different look. First, it appears more withered: the bracts are yellowing and wrinkling. Second, these bracts are not snuggly whorled around the ripe seed pod; thin, light-green sepals partially curve down between the bracts. This is a characteristic of T. recurvatum. Also, interestingly, our patch of T. recurvatum, located under our native witch-hazel, is completely done for the year―nothing is above ground at this time.

The withering individual was snipped for closer examination.

One sepal is curved down; one sepal is curled on itself; and one sepal is stretched out with a partial downward curve. This description doesn't fall in line with either T. gracile or T. recurvatum. Perhaps it is one of the other many different trillium, such as T. foetidissimum or T. ludovicianum.

Six small seeds were collected and planted in a completely different location. Hopefully something will come up!

 

Next spring, we ought to measure and smell the fresh trillium flowers. Have you ever thought to smell a trillium flower? I hope not. The reviews are less than favorable. In Louisiana, you run the risk of encountering the odor of rotten meat. Yuck! What critter is attracted by this foul stench? Such undesirable tasks as sniffing the flowers will help us carefully classify the trilliums that the arboretum has in its collection. In the interim, check out the "Key to Trillium" from the North Carolina Botantical Garden for all of the different trillium characteristics.

 

From the USDA Forest Service, you can find a little more information about the the four species shown on the above map:

Trillium ludovicianum

Trillium gracile

Trillium recurvatum

Trillium texanum

Tree of the Week: Honey Locust (Gleditsia triacanthos)

This past spring, prompted by its display of tiny, fragrant flowers, we discussed the history of the arboretum's honey locust (Gleditsia triacanthos). In 2013, we collected seeds but incorrectly identified the source as a black locust. These were germinated in the campus greenhouse and one specimen was planted in the arboretum in April of 2015. It has now been a decade since the seeds were collected, and this year, we have our first fruits. 

During this past summer, we observed pods growing on the tree. They were high up, on the upper branches, far out of reach. This week, two fruits were incidentally discovered on the ground. One pod was found under a nearby groundsel bush, and then we picked up another pod directly under the honey locust, next to its trunk. What luck! These two fruits are shown in the photos below.

Honey locusts produce long, leguminous fruits. The two pods in the above photograph are ripe. They each measure between six inches to one foot in length. They are black, twisted, bumpy, hard and the seeds could be heard rattling inside their individual cells. It is said that honey locust pods have a sweet pulp, but nothing on the interior of these ripe fruits suggested sweetness; perhaps, in order to experience the honey of the honey locust, the fruits need to be collected before desiccation.

 

From two pods, 19 seeds were collected. The seeds are brown, with an oval shape, and measure more than ¼ inch in length.

 

So, within a decade, the honey locust has developed from a seed into a very tall tree that is now producing fruit. That's rapid development!

Seeds

 

In the middle of December, near the winter solstice, tag alder fruits are ripe.

Seeds can be seen dangling from the miniature cones.

Mature fruits resemble tiny pine cones. Each cone measures half an inch in length. Some cones readily release seeds when jostled; other cones need to be bent and pulled to shake seeds loose.

Seeds are small and numerous. How do we get them to germinate? Pull up the grass; scratch the earth; sprinkle seeds; cover seeds; water; wait. If nothing happens, try again next year.