Normally at this time of year, people plan drives to take a look at the changing fall colors. But this year, Arkansans are wondering if there will be any fall color.
It has not been our best growing season, with a miserably hot and dry July followed by an even drier September and early October. Add in an earlier than normal freeze, and our trees have had a tough time.
Some parts of the state did get some rain this past week, but will it make enough difference to trees and shrubs as they head into their dormant season? What affects fall color in the landscape?
The most vivid display typically occurs when trees experience cool nights and warm, sunny days — which we have had in abundance. But ample soil moisture is another factor, and that has been lacking for most of the state. Also, some trees shut down early thanks to the dryness and have already shed their leaves.
But some species are beginning to put on a bit of a show. Time will tell how good it gets.
During the growing season, the leaves on most deciduous trees are green, with the exception of some species, like purple leafed plum, that have purple leaves; some Japanese maples with red or variegated leaves year-round; and other hybrid species bred for various colored foliage. During the growing season, the not-green pigments on green trees are covered up by the green from chlorophyll.
If you remember your high school biology classes, plants manufacture food from sunlight using chlorophyll in a process called photosynthesis, thus keeping leaves green. As day length gets shorter and weather cools, that chlorophyll in the leaves begins to break down as trees prepare for dormancy. As the chlorophyll breaks down, the green color starts to fade away, and extra sugars in the leaves allow the underlying natural pigments to show their colors.
All plants — like people — contain different pigments. These innate pigments are what allow some trees to turn yellow, orange, red or purple in the fall. Unfortunately, some trees just turn brown.
The pigments responsible for color change are:
◼️ Carotenoids, which produce yellow and orange colors, and
◼️ Anthocyanins, which produce red, purple and pink.
The type of growing season we have, available moisture and gradual temperature changes all play a part in how pretty our fall foliage becomes. Frosts play no part in fall colors. In fact, frost actually damages the compounds that produce the fall colors, encouraging leaf shed.
Lower nighttime temperatures — especially in the 40s and 50s — do help with fall color. But an early frost can shut down fall foliage quickly, depending on how cold it gets, while a late frost like the one we had last year extends the color palette.
RED MAPLES VARY
Different trees contain different pigments. While it is true that some trees are well-endowed and add reliably vivid colors to the palette — think Japanese maples, sugar maples and ginkgoes — not all trees in a species are created equal. A good example is red maples.
Some native red maples do turn a beautiful shade of red in the fall, but others can turn yellow, orange or even brown. To be guaranteed a pretty fall red maple tree, either buy a named variety such as Autumn Blaze or Red Sunset, or buy your red maple in the fall when it changes color and you can see those colorful leaves on the tree you're buying.
That's a smart tip for buying maples, but really, if you want a specific fall color in any species of tree, choose your new tree in the fall, when the fall colors are showing. Fall is also an ideal time to plant a tree.
◼️ Typically, our most reliable fall color comes from native blackgums, sweetgums, maples, sassafras, sourwood, Kentucky coffeetree and dogwoods.
◼️ Non-native trees with good fall color include Chinese pistache, ginkgo, crape myrtle and Japanese maples.
◼️ Some years our oaks and hickories are showier than others.
◼️ Flowering pears — including Bradford pears — have outstanding fall foliage, but have become extremely overplanted and are now considered invasive.
Deciduous trees aren't the only plants showing off in the fall. Our roadways are dotted with red sumac leaves, in addition to their showy cones of fruit. The better-behaved cut-leafed sumac is golden in the landscape.
Burning bush (Euonymus alata) has a phenomenal red show in the fall, while witch hazel, fothergilla, itea and oakleaf hydrangea turn shades of red, yellow or orange. And Arkansas amsonia turns a wonderful shade of yellow before going dormant.
While not welcome in the garden, poison ivy and Virginia creeper turn glorious shades of red or purple before shedding their leaves, too.
There is no precise date for when the peak fall color will occur in our state, and it usually doesn't last a long time. It normally starts in late September in the northern tier of counties and ends in mid-November; but that all depends on weather conditions.
The Arkansas State Parks division tries to track it, with an advisory website that relies on end-users to upload photos. See that site at arkansasstateparks.com/activities/fall-colors.
There are also designated scenic highways in the state that are beautiful year-round. See arkansasonline.com/1022route.
AFTER THE SHOW ENDS
Whether we get a showy fall or we don't, if you have deciduous trees in your yard, once the show is over, your job begins.
Raking of fall leaves is an annual chore. Whether you mulch the leaves or bag them, if you have a grass lawn, you do need to get them off the lawn so it doesn't smother or develop diseases.
Composting is a great way to turn the leaves into usable organic material to help enrich your gardens. Shredded leaves make a great mulch.
Fall foliage marks the end of our growing season and the onset of winter. Get outside and enjoy the crisp, fall weather and, hopefully, the show that Mother Nature will provide.