Cherries

I inevitably overlook cherry trees (Prunus sp.). I don't know why. In the spring, I look forward to the crabapples, but then am always insensibly surprised by how beautiful cherries are in the spring.

I've mentioned them in passing once and mused on the poor use of the potentially beautiful weeping variety, but I've never acknowledged the lovely fall color they have.


The above is taken outside of the Stuyvesant town apartments - but all around the city I have noticed how lovely cherries look this time of year. The fiery oranges and sunburst yellows contrast well with the trees' dark bark and the evergreen Pachysandra beneath.


Cherries area always easy to spot, even in the winter. They are a coarse-limbed tree with a dark brown - almost black - bark with a rosy pink undertone. Of course, more notable than the color is the bark's smoothness, punctuated with lenticels. (Lenticels are specialized 'pores' in the bark that aid in gas exchange.) The easy way to describe cherry bark is to say it looks like Shantung or raw silk.



But if you weren't convinced you had encountered a cherry, and the leaves were still on the tree, you could look for the small 'pimple' at the base of the leaf's petiole. That is typical to Prunus.




I haven't used a species name in this post, primarily because cherries are so often hybridized. This plant is most likely a Prunus serrulata, but it could be a hybrid of several species.

Sugar Maple and a Brief Explanation of Fall Color

When it comes to fall color, the sugar maple (Acer saccharum) may be king.



This specimen is turning yellow, but you can find sugar maples turn fiery orange and red as well.

A commenter asked earlier this week why leaves turn different colors in the fall, and now I'm going to attempt to answer in just a few short sentences....


Most people know that chlorophyll is the chemical compound in plants that is necessary for photosynthesis (the production of sugars and carbon dioxide in a plant). Chlorophyll is also a pigment that absorbs the blue and yellow colors from sunlight, making plants appear green. The more chlorophyll in a plant, the more green it appears (and also, the more energy it produces and in some cases, the faster it grows -- it's generally why green-leaved plants grow faster than their variegated counterparts).

In the fall - as the days become shorter and colder - a membrane grows between the twig and the leaf petiole which clogs up the flow of sugars and water between the leaf and the rest of the tree. This eventually prevents the chlorophyll from being productive and the compound breaks down.

That's where carotenes and anthocyanins - two other pigments in leaves - come in to play. These pigments exist in the leaf all year, but are overpowered by the presence of chlorophyll until autumn. The former absorbs blue-green and blue light, which means that the presence of carotene - once the chlorophyll is gone - can make a leaf look yellow. Anthocyanins absorb blue, blue-green and green light, which makes a leaf appear red. The amount of anthocyanins and carotene varies among species (and in the case of sugar maples, they vary among individual plants).


So now, when you see a tree that has yellow fall color, you can impress your friends by observing that said tree must have a high concentration of carotene. I'm sure they'll be fascinated!

Back to sugar maples, briefly. Sugar maples of course are responsible for maple syrup and, as the common name would imply, the tree's sap is quite sweet. They are also very hard-wooded trees and the lumber is used for basketball court floors, pool cues and bowling pins.

My students struggle with discerning differences between sugar, silver, Norway and red maples. I'll post some of these other species in the days to come. The important characteristics to look for in sugar maples are a smooth or entire leaf margin and furrowed bark. While Norway maples also have entire margins, their bark is more stripey (and the leaf petiole exudes a white milky substance). Unlike sugar maples, red maples have serrated edges and silver maples have deep leaf sinuses.

Acer comes from a Latin word for sharp - referring to the hard wood, which could be utilized to make spears. Saccharum means 'sugar' - like saccharine.

Daylength & Fall Color

I am a little bit fascinated by the circadian rhythms of plants, so I can't help but share a photo of these dreaded Bradford pears growing in southern New Jersey.

Check it out:



So, on one side you have a row of trees that are still fairly green. On the other side of the street, the trees are at their fall color peak. If you think about it, it makes perfect sense: The trees that are further along in their procession to dormancy (the red ones) are on the south side of the street. They sit just north of the adjacent townhome, which reduces the amount of daylight they receive. The trees on the left have slightly more day-length and thus won't turn color at the same time as their neighbors.

This was such a great illustration of how day-length influences fall color that I had to use it, even if it was the lousy pear tree.

Ginkgo biloba

This woman has hit the motherload as far as harvesting Ginkgo biloba fruit goes. These large specimens were indeed female and had a substantial, smelly bounty.


New Yorkers may not know this tree, nor know that there are female and male specimens, but they have probably smelled the ginkgo before. The smell is most aptly described as similar to vomit or dog waste, or a mix of the both. That doesn't prevent people like the woman in the photo - protected with latex gloves - from collecting the fruit. Ginkgo biloba is traditionally used by Asian cultures for tea and, of course, is a popular herbal remedy (promoting brain power) at the drugstore.


Now is as good a time as any to note that calling this a fruit is in fact a misnomer - ginkgoes are gymnosperms, which means that they are not flowering plants. Despite the fact they are broadleaved deciduous plants, they have more in common with a pine or a spruce than an oak or maple. Technically the woman in the first photo is collecting 'naked seeds.' Gymnosperms are more primitive plants than angiosperms (flowering plants) and the ginkgo's evolutionary history dates back over 150 million years. It is a living fossil.


Despite its homeopathic applications, female ginkgo trees are not commonly planted - 'never plant a female ginkgo' could be considered the horticultural equivalent of 'don't spit in the wind' - and they are on the Parks Department's list of noxious plants. Instead, the male plants are used, as the tree is nonetheless beautiful and, for the same reason that it has survived for so many millions of years, is very tolerant to urban conditions like pollution, compaction and drought.

Mystery Aesculus

I was in Central Park last weekend when I stumbled along this species of Aesculus. I was quite taken with it -- the golden foliage was brilliant and it had a regular, columnar form.



It's not a horsechestnut (Aesculus hippocastanum) and certainly not A. parviflora or A. pavia. From anything I read about A. flava and A. x carnea, it seems the bark is too smooth. I am completely baffled. It could perhaps be A. chinensis or A. indica, though they both seem to be fairly rare, and the description doesn't seem to quite fit. This tree was like a buckeye on the trunk of a tuliptree...


Does anyone know what this is? Please, please tell me!

If not, I suppose I will have to wait until spring and see if the flowers give us any better clues!

Witch Hazel Fall Color

This fall color was too pretty to ignore -- it's Hamamelis x intermedia, or witch hazel. I've posted photos of this plant blooming in the gray winter, but the oranges and yellows that you can get in autumn is an equally good reason to use this plant. Our native witch hazel, Hamamelis vernalis is also a popular plant, but it has a more consistently yellow fall color.



The word Hamamelis is Greek and is a reference to a plant that flowers and fruits at the same time. -Melis is derivative of the Greek word for apple (similar to Malus, the actual genus for apple and melon). The common name is due to the fact that divining rods were historically made from this plant.

Black Tupelo

Like any single woman in Manhattan, I have been looking for a great specimen of black tupelo, or Blackgum, or Nyssa sylvatica for years and years.

Finally, last Saturday, I stumbled across it in Central Park's Ramble.


Black Tupelo is identifiable by its simple leaves with entire margins. The branches protrude from the trunk at 90 degree angles when the tree is young, but as it gets older, it has a pendulous and sprawling habit.


Another way to spot it -- if you aren't sure you're looking at blackgum, is to check out the telltale three dots above the bud scar.




Black Tupelo is a favorite tree of mine -- and I am not alone in my unconditional adoration. Dirr raves about this tree and its ability to exhibit the most brilliant and consistent fall color.

Really: what a beauty, eh?



Nyssa is rarely seen in parks or sidewalks as it's not the most low-maintenance tree. It has a tap root so it doesn't like to be transplanted at larger sizes and prefers well-drained soils. And more so, I think it would be all wrong in such a location -- its allure is partly due to the way it can stop you in your tracks in a natural location. And it certainly needs some room so it can stretch out enough to really show off.


Nyssa sylvatica literally means 'water nymph of the forest.' Nyssa is Greek for 'water nymph'; sylvatica means 'of the forest.' The word 'tupelo' is derivative of the native American term, ito opilwa, which means 'swamp tree.'

Now then: go out and vote!!

Serviceberry

I have raved enough about Amelanchier -- both A. arborea and A. canadensis -- that I don't really need to make this a long post.

But I did need to point out it's terrific fall color.


These are from one of my favorite parts of Battery Park -- it's the Cove area, which is just near the southernmost tip of the park. That's Gleditsia bark in the foreground.

Serviceberries aren't always yellow -- some specimens have an orangey-red fall color and some are even darker red.

Honey Locusts

Obviously, this is the time of year to post some good fall foliage photos. More and more, I am also considering honey locust (Gleditsia triacanthos var. inermis) to be in the underappreciated category for autumn color. Right now, these trees -- so common in NYC -- are at various states of undress. Some have full canopies of green leaves, others have begun to turn a burnt-gold color, and others have completely defoliated.


Gleditsia is unusual for it's heterophyllic foliage. At times, the plant has a basic, pinnately compound leaf. That means that the leaf consists of smaller leaflets, all arranged on a straight line (horsechestnut, on the other hand, has a palmately compound leaf; leaflets are arranged like fingers from a palm). In addition to the pinnately compound leaves, honey locust can also have bipinnately compound leaves -- that means that the individual leaflets are compound and are composed of sub-leaflets. You can see both leaf types in the photo below; while the branch in the center of the photo has mostly pinnately compound leaves, the branches to the right and left have bipinnate leaves.

The trees below - sitting next to the Hudson - have lost all their leaves. It's a good chance to see the winter habit.


To me, this is a very recognizable tree in the winter -- the branches are knotty and have a zig-zaggy habit. The bark is also quite dark and will occasionally peel in thick plates.


Gleditisia's genus is named after a German botanist. Triacanthos means three-spined and conversely, inermis means thornless. The botanical name makes more sense when you realize that the straight species of honey locust is very thorny. You can occasionally see thorned honey locusts in the city -- in Central Park there are a few near the statue of the Polish King Jagiello at the east side of the Turtle Pond -- but most of the time these trees will be thornless.

Zelkova

It occurs to me this autumn that I have been selling Zelkova serrata, or Japanese zelkova, short when I teach it to students. I never make a note of its fall color and as you can see here, it's fall color is radiant.


(sorry that this is a bit fuzzy -- I took these shots early this morning and now, with our diminishing daylight, it's hard to get a flash-less photo!)

For a time, people thought zelkovas may be the best replacement for the American elm, which was slowly dying out due to Dutch Elm Disease. If you read Dirr's entry on this plant, you can see that he's passionate about the zelkova's potential and at the same steadfast in that no plant, no matter how lovely, could ever replace Ulmus americana.



The two trees are related -- both are in the elm, or Ulmaceae, family. The vase shape you see above is common to plants in this family, as is an asymmetrical leaf base.

Here's a shot of the very distinctive bark. Zelkovas have smooth gray bark and, as the tree ages, the base of the bark has blisters, exposing a cinnamon-colored inner layer.



The wood on zelkova is quite hard and has been used to make furniture in places where the tree occurs naturally. Zelkova's name, as you may have guessed, is not derivative of Latin or Greek. Instead it is from Caucasian name for the tree, dzelkva. Dzel- means bar, and kva means rock, indicating that the rock-hard wood can be used as a bar in construction.

Katsuratree

Katsuratree (Cercidiphyllum japonicum) is one of my favorite trees for fall color. In fact, it's simply one of my favorite trees (at least in the small, ornamental size). This is what it looks like right about now.


One of the other remarkable things about this tree is its wonderful texture. This is partly attributed to the very unusual leaf margin. The leaf margin is the edge of the leaf. Some leaves have a serrated margin (like Ostrya virginiana, for example) while some are entire (Quercus phellos). The leaves on Cercidiphyllum have a scalloped leaf margin and look like they have been cut with pinking shears.


They also sit on the branches in a striking manner -- evenly ranked and with leaves perpendicular to the ground.

You can also see that this is one of those few trees with leaf orientation that is not opposite, not alternate, but sub-opposite.


Of course, the long fibrous strips of gray bark isn't too bad either.


Cercidiphyllum is named for having Cercis-like leaves, as the heart shape leaf certainly appears on both of these species.

Parthenocissus quinquefolia

Parthenocissus quinquefolia, or Virginia creeper, growing up along the boardwalk rail on the Jersey shore.


Chances are you have noticed Virginia creeper these days. It is a climbing vine and while it's inconspicuous growing along the trunk of a tree in the summertime, it's hard to miss right now, as the leaves are turning a brilliant crimson red.



It's fruit are also maturing and will soon be eaten up by birds. The fruit on this native vine are high in oxalic acid and can be fatal to mammals. It's apparently also awful-tasting, so deaths by Virginia creeper are fairly rare.


Parthenocissus is literally Greek for virgin ivy. 'Parthenos' means 'virgin' and the Greek work for ivy is 'kissos.'