Sunday, October 16, 2011

Native Fall Foliage - Yellow

Fall color is spreading in my area.  What a beautiful sight - it is almost as if the trees were flowering again.  Generally the colors of tree foliage fall into 2 color groups: yellow and orange/red/purple.  I've decided to do one blog entry devoted to each group.  This entry is Yellow.

A southern form of Sugar Maple, perhaps Acer barbatum

Of course there is a lot of variation in fall color even for the same type of plant.  For example, I've seen Red Maples (Acer rubrum) that turn yellow, others that turn orange/red, and others that turn red/pink.  These differences can be attributed to many factors (and here is an excellent site to explain it):

  • Individual plant differences:  This is how cultivars are developed.  Acer rubrum 'October Glory' was a single plant that was selected for dependably rich red color in the fall.
  • Climate differences:  Was it wetter than usual, drier than usual, cooler or warmer than usual where this plant resides in the days leading up to autumn?
  • Different locations: Some trees change color earlier in one location than another even when they are just a few miles apart.

Most people have learned at some point that chlorophyll is what makes leaves green.  It is when trees stop producing chlorophyll that the "true" colors come out.  Different trees have different amounts of the components that make the different fall colors: Carotenoids - Browns, yellows and oranges and Anthocyanins  - reds and purples. So given those all those explanations, here are the “usual” yellows that I can expect to see in my area:

Two maples here, one is Red maple which often turns yellow in the wild, but sometimes turns orange/red.   There are maple cultivars and hybrids that reliably turn red or orange.  If what you are seeing is a landscape plant (like in a parking lot or business/residence landscape), chances are it is a cultivar and the color would not be yellow.

Southern sugar maple has the leaf shape of a Sugar maple (Acer saccharum) but the color is a pure, deep yellow while Sugar maple turns yellow/orange.  Another local maple is Chalk maple (Acer leucoderme) which has a similar leaf, but it turns more orange/red in color.  The leaf of the Chalk maple usually is pubescent (has fine hairs, feels fuzzy) on the underside.

Red Maple, Acer rubrum

Southern Sugar Maple, Acer barbatum

Black cherry, Prunus serotina

Persimmon, Diospyros virginiana

The next pair of leaves look similar at first glance, both turn a soft yellow and have a similar elliptical shape, but the cherry has a toothed margin where the persimmon does not.

I spent several days this week looking around my yard and neighborhood for leaves to photograph.  Now that the leaves are changing color, it was a shock to realize just how many young persimmons I have.  I know there are fruiting persimmons in my neighborhood (you can see a picture of the fruit in one of my posts from last year), but I've never seen fruit on mine.  Only one of mine ever blooms (the others are too young perhaps), and it would need to be a female to set fruit and would need a male nearby for pollination.
Tuliptree, Liriodendron tulipifera

Muscadine grape, Vitis rotundifolia

Tuliptree (Liriodendron tulipifera) is generally very boring when it comes to fall color.  Leaves drop early in the year so that by the time fall color season arrives half the leaves on the tree are gone and the rest turn a spotted yellow, a few at a time.

Muscadine grape (Vitis rotundifolia) is a plant not much noticed throughout the year, but when the leaves turn yellow - often in advance of neighboring plants - it shows up.  It is especially noticeable twining through pine trees because the yellow foliage just pops out of the green branches.

Bottlebrush buckeye, Aesculus parviflora

Pawpaw, Asimina triloba

Buckeyes (Aesculus spp.) also lose their leaves early in the year - I was hard pressed to find an example of these compound leaves that still have the original 5 leaflets attached on a group of leaves.  Sometimes the color is more soft orange than yellow.

The large, tropical-looking leaves of Paw Paw Asimina triloba) quickly fall off once the leaves turn yellow.

Musclewood's (Carpinus caroliniana) petite, toothed leaves and thin branches are easily confused with Hophornbeam (Ostrya virginiana).  The fall color doesn't offer any better clues - they both turn this nice shade of yellow.

Redbud's heart shaped leaves are very distinctive but unfortunately the fall color is not.  While much favored for it's early purple blooms in the spring, the yellow, spotted fall leaves are nothing to comment on.  This is a picture from my 'Forest Pansy' cultivar (Cercis canadensis 'Forest Pansy') - I'm not sure if that orange color is attributed to the cultivar, but it is certainly is an improvement over most wild plants.

Musclewood, Carpinus caroliniana

Redbud, Cercis canadensis 'Forest Pansy'

Compound leaves often confuse people in the fall because the leaflets can fall off in advance of the leaf itself, making it look like the leaflets are indeed true leaves.  Green ash (Fraxinus pennsylvanica) and Hickory are two of the ones I show here.  The ash leaf turns a pale yellow while the Hickory (Carya spp.) is a deep, almost orange-yellow color.  Hickories can be tall trees - they are quite striking when the whole tree colors up.  Around here, they are an essential part of the yellow-red-green landscape that people think of in the fall.

Green ash, Fraxinus pennsylvanica

Hickory, Carya sp.
Other native trees around here with compound leaves that turn yellow are pecan (Carya illinoinensis) and walnut (Juglans spp.).

Bigleaf magnolia, Magnolia macrophylla

American beech, Fagus grandifolia

The deciduous magnolias are especially noticeable this time of year, particularly the large leaves of this Bigleaf magnolia (Magnolia macrophylla). The shorter tree with the darker colored leaves to the right is Umbrella magnolia (Magnolia tripetala).  

American beech turns briefly yellow then transitions to a soft caramel color.  Young trees will retain their leaves during the winter and the leaves will fade to a pale tan, almost the color of old lace.

Other leaves that turn yellow/brown in the fall (and which are not pictured here) include:

  • Sycamore (Platanus occidentalis)
  • Some oaks like Post oak (Quercus stellata) and Water oak (Quercus nigra)
  • Mulberry (Morus rubra)
  • Sugarberry/Hackberry (Celtis spp.)
  • American smoketree (Cotinus obovatus)

and sometimes Sweetgum (Liquidambar styraciflua), but it also turns purple so I'll show that in the next post.  Next week I'll go through all the ones that turn orange, red, pink and purple.


  1. Very informative as always. I just fear that someday there will be a pop-quiz and I'll be toast! Did you get enough rain in your area over the summer months? We did not and many trees dropped leaves or looked sad.

  2. We were a little dry in the hottest months. We pulled in a little rain just in time to get decent color, I think. Don't worry, all my quizzes are open book.

  3. How very lovely fall is all dressed in gold. I especially love the Big Leaf Mag!