Sunday, November 6, 2016

Reds Made on Purpose

Norway Maple fall color
A most interesting discussion has begun about a process that most of us marvel at each year and that is the turning of leaf colors.  We know that in the fall (or autumn if you prefer) when it starts to get colder, and daylight gets shorter, the chlorophyll that turns leaves green starts to break down and reveal the underlying cartotenoids, which then turn leaves yellow or orangey. This is familiar to us, but what about the reds? Those glorious reds? All the way back on October 25, 1936, in the New York Times Charlotte Wallum wrote “The red pigments are cell-sap colors.  They are supposed to be tannoid compounds (referred to as anthocyanin) and the pigments of red beets and dark grapes are similar compounds.”

Now eighty years later to the date, October 25, 2016 in the New York Times, Joanna Klein takes another look at this familiar yet extraordinary process in her wonderful article, “Why Does Fall Foliage Turn So Red and Fiery? It Depends.” Klein begins her article poetically, “Leaves scream their final cries in color before dropping to the ground.”  She reminds us of the normal break down of chlorophyll and the revealing of the underlying yellow or orange in most leaves.  Klein then explains that the story of the red leaves is different.  Red leaves are “made on purpose.”  She tells us that the anthocyanins that are produced come from built up sugars in the leaves that combine with the green pigments left in the leaves and turn into different shades of red depending on the species, the environment, and its own genetics.  Clearly eighty years later, scientists understand the process better.  But even today, they are asking why some leaves use their “precious energy” to turn red before they die.  Several theories have been posited: They may be flashing color to attract birds and mammals to their tree’s fruits hoping that they will be eaten and the seeds dispersed.  Or the red leaves could be a warning about the bad-tasting poisons or chemicals in the leaves so they should be left alone and not used as sites for pests wanting to lay eggs.  Or the red color could signal that the leaf is dying and not to be eaten because it has no nutrients.  And finally there is Robert Guy, a professor of forestry at the University of British Columbia who wonders if the red “works like a sunshade in maple trees.”  According to him, the red leaves may serve as a protection from bright and UV light so that the leaves have the time to send their nutrients back into the tree for storage before they drop to the ground. 

I don’t know how many of us will be around eighty years from now, but I certainly hope the maples, the aspens, the black tupelos, the sassafras, and all the other trees whose leaves turn red will be.  In fact, I hope all the trees and natural life of this planet will be. But for now, let's take joy in the glory of the reds, and the glory of the fall. 



Monday, October 31, 2016

Black Cherry Treats

Watercolor of Black Cherry leaves and berries
As part of the proposed February 2017 opening of the Cabrini Woods Nature Sanctuary, near Fort Tryon Park, I was asked to draw a leaf of the Black cherry, Prunus serotia.  Planning a drawing involves a few steps including finding pictures online, in books, and going to look at the actual trees.  I knew there were several black cherry trees in the Ramble in Central Park, so I went to see them.  I soon realized that in drawing the black cherry, I would need to include the cherries that the trees produce, berries that are almost entirely gone by this time of year.  These cherries are food for all kinds of wildlife especially squirrels and birds who eat the berries when they are red or purple, but we humans generally wait to eat them until they are so ripe that they turn blackish purple.  Interestingly, when you look at a group of cherries on a branch, you see them in a variety of colors and ripeness and that is what I wanted to show. 


Black cherry trees are members of the Rosaceae or Rose family – a family that includes apples, pears, peaches, plums, apricots, almonds and many vines like strawberries, blackberries, and roses of course.  Black cherry trees produce flowers in the early spring, long pendulous blossoms that bees enjoy.  And then there are the cherries.  Like apricots and apples, the seeds contain compounds that can be converted into cyanide which can be released if the seed is ground or minced, but the flesh does not contain the enzyme that converts the chemical into the dangerous form of cyanide. However, there needs to be a word of caution about the foliage.  When it wilts, it contains a chemical that converts it into hydrogen cyanide if eaten by animals.  Farmers with grazing animals need to be aware of this, and they often remove these trees so the livestock do not eat the wilted foliage.  But for most of us, the trees do not pose a problem—we eat the cherries and not the leaves.  The black cherry timber is renowned for its beauty and durability.  The trees themselves grow easily in the urban environment and are replanted through the droppings of the animals who eat the cherries.  It is exciting to research a plant and to have the opportunity to draw it, especially knowing that it will be used as part of the signage in what will be a nature sanctuary in one of the loveliest parks in the NYC area. 

Monday, October 3, 2016

Celebrate coleus

Drawing of coleus leaf
In this transition from summer to fall, a rarely celebrated plant is having a bit of a heyday—the coleus or painted nettle.  I’ve been noticing multicolored coleus leaves popping up at the base of trees all around both the west and the east sides of New York City.  Once fall leaves emerge in their full magnificent palette, we may not notice the coleus and they will die away when the cold days arrive, but for now, they are a source of a great beauty—a huge range of brilliant colors and sizes from under an inch to some more than 6 inches in size, like the one that I drew.  There are more than 600 varieties of Solenostemon scutellarioides, formerly known as Coleus blumei and Coleus x hybridus.  These lovely plants are native to India, Thailand, and other areas of Asia and Africa.  Their shape and texture always reminded me of mint leaves and sure enough, I found they are from the same family: the Lamiaceae family that contains peppermint, salvia, lavender, thyme, basil, and oregano among others. 


For those of us who were not born with a green thumb, coleus are good to know about because they are easy to grow and to propagate.  They also reward you since if you water them when they get droopy and withered, they will spring back to life like a little smile when you water them.  If only it were so easy for all of us to accomplish this feat.  There is also a little trick to keeping them growing bushy and not spindly and that is to pinch off their flowers before they get growing.  By the way, they don’t do well in the winter, like a lot of us, so you need to bring them in if you want them to survive the cold weather.  The National Gardening Association has a great entry on the coleus plant: I was fascinated to read that “coleus are frequently used as `lab rat’ plants” and so are tested for everything from salt tolerance, water uptake, plant nutrition, leaf morphology, etc.  They are even testing them to see if “coleus cell cultures may be useful in production of a compound called rosmarinic acid which has anti-viral, antibacterial, anti-inflammatory and antioxidant properties.”  In India, the roots of coleus plants have been used in Ayurvedic medicine to treat heart and lung diseases; in addition, the chemical Forskolin, found in the tuberous roots of some coleus varieties, may be used to help us burn fat, build bone mass, as well as support healthy testerone levels. No bad, right? So keeping all this in mind, I think it is time that we celebrate the colorful, easy-growing, and possibly medicinal coleus.