This morning was sunny and warm, around 80˚ F, when we started our walk at 11 am. Later in the afternoon it was windy, rainy, and cold, so we were very lucky on our timing. There were 15 guests, which was our limit. Gail R. gave a brief introduction, and we were on our way.
Our theme was searching for color. All were happy to help with this. The first stop was a persimmon tree (Diospyros virginiana) loaded with yellow fruit and yellow leaves. Next someone spotted some yellow and purple leaves, which were identified as sweet gum (Liquidambar styraciflua). These can also have some orange color, but not this year. Nights have not been cool enough. Color appears after the leaf scar develops—water can’t get in, and the sap can’t get out. The scar starts the disappearance of chlorophyll or green color and later leaf drop. This green color had been masking the yellow color. When the sugar is blocked and it can combine with another compound and form anthocyanin, the purple color appears. These colors first appear along the edge of the forest, where there is the most sun.
Later, we noticed some milkweed pod seeds (Asclepias syriaca) and their silky parachutes ready to disperse the seeds. Insects were also busy on the pods. Farther along, we noted some devil’s walking sticks (Aralia spinosa) because of their lovely tops with red pedicels left from the flowers and a few blue-black berries still attached. Most berries had been eaten. We also passed more persimmon trees, with green leaves turning yellow.
Standing guard at the entrance to the woods was a dogwood (Cornus florida) tree full of red berries and flower buds for next year. The leaves were a lovely purple. The birds will eat these berries soon after the first frost, when they are very tasty. Crossing the first bridge, we marveled at the green ferns that were still showing. The ferns will disappear with the first frost. Next were some paw paw (Asimina triloba) trees with some very large yellow leaves tinged with brown. More bright yellow leaves spotted on the trail were shaped like a cat’s face and came from the many tulip trees (Liriodendron tulipifera) in our woods.
Later, we saw some green leaves of the cranefly orchid (Tipularia discolor). These green leaves have a deep purple underside. Anthocyanin is thought to help plants by shielding them from the ozone in the atmosphere and absorbing free radicals produced during metabolism. More red leaves and dark berries were spotted on the winged sumac (Rhus copallinum) as we left the woods. Someone noticed the purple pokeweed stems (Phytolacca americana). This inkweed is aggressive but not invasive. It is native.
Someone pointed out some bushes with unusual seeds that were purple on top and red berries in the pods. They are hearts a- bursting, or strawberry bush (Euonymus americanus), with leaves that turn red in fall. This is our native viburnum, and is not invasive like the burning bush. Another guest spotted some red berries on false Solomon’s seal (Smilacena racemosa) that had not been found by the birds yet. We also spotted some striped wintergreen and downy rattlesnake plantain orchid leaves, which are mostly green and were almost hidden by the fallen brown tree leaves.
Finally, we got to the Pavilion and our peach smoothie lunch with colorful veggies, fruit, brown bread, and cheese. Also some dark chocolate, which disappeared? The colors were to remind us of the color we had seen on our walk. Later we talked about eating veggies for their flavor and our health. We discussed ways to prepare them that are healthy and tasty and will help us get the nutrients we need. There were many questions, and we had a good discussion.
Our helpers were Marilyn R., Denise D., Gail R., and Joyce W., with Michelle and Lisa helping and at the front desk. Thank you all. We have one more program in November, and many said they had already signed up. Great!!
by Julianna Pax
Arboretum docent/Maryland Master Naturalist