Concentrated in the leaf, sugars react with proteins in the cell sap to produce anthocyanin, a purply red pigment that causes apples to turn red and black grapes purple. Crucially, the production of anthocyanin is boosted by sunlight, drought and temperatures staying above freezing.

autumn leaves

autumn

As for the rest of us farther south, we’ll likely have to wait until mid-October before the leaves start changing across the lower half of the country. Peak foliage across the U.S. will most likely appear between the last week of October and the start of November.

Five Fall Color Trends from the Runway

• Sorbet Pink. Imaxtree. Pink has long been a romantic color among the fashion set, but it’s staging a triumphant comeback in a pastel hue this season.
• Green with Envy. Imaxtree.
• Earth Tones. Imaxtree.
• Shades of Gray. Imaxtree.
• Head-to-Toe Black. Imaxtree.

Sit tight: Many of the Southern states have yet to experience their peak season for fall foliage.

• The Berkshires.
• Utah.
• Great Smoky Mountains.
• Columbia River Gorge.
• Arizona and New Mexico.
• The Ozarks.
• West Texas.
• Northern Louisiana.

TOP TREES FOR FALL COLOR

• APPLE SERVICEBERRY (Amelanchier x grandiflora ‘Autumn Brilliance’)
• RED OAK (Quercus rubra)
• QUAKING ASPEN (Populus tremuloides)
• DOGWOOD (Cornus florida)
• SASSAFRAS (Sassafras albidum)
• BITTERNUT HICKORY (Carya cordiformis)
• SUGAR MAPLE (Acer saccharum)
• AMERICAN PERSIMMON (Diospyros virginiana)

Abundant dry weather and sunlight lead to more sugars in leaves, which in turn leads to brighter fall reds. This is a separation layer of cork-like cells that develops between branches and leaf stems in response to shorter days (in reality it’s the longer nights) and cooler temperatures.

Late September is when leaves begin to hit peak colors in some states. By September 21, 2020, the map shows that parts of Colorado, Wyoming, Utah, Montana, Michigan, Minnesota, Wisconsin, New Hampshire, Maine, and Vermont will be at or near peak fall foliage, which is typical for peak timing.

Areas covered in green indicate that the leaves have not experienced any change in color. Leaves found in Florida, Alabama and other southern states have not experienced any change. Thus, they are presented as green on the map. After green is light yellow, which describes a minimal change in leaf color.

Prolonged warm weather could delay peak colors, experts say. Autumn officially begins on Tuesday, September 22, 2020. This summer’s prolonged warm weather could delay peak fall foliage. Some leaves will begin changing color in early September, with most of the country seeing changes by mid-October.

True, Florida does not have the dramatic color changes seen in other parts of the country. True, many of our trees, from the magnolias to the live oaks, remain green year-round. Moisture can also affect how dramatic color changes are. The wetter it’s been, the more likely leaves will be dull.

But to see Florida’s best fall color, you must head north from late October to mid-November. Torreya State Park in the Panhandle, west of Tallahassee, is one of the oddest places in the state, in part because topographically-speaking, it’s more like North Carolina than the state’s typical flat pinelands.

However, there are many native trees of Florida that will lose their leaves in the winter but they will not change because even though the days may be getting shorter, the temperature at night is too warm for them to change. So, instead of having colour on the leaves, they stay green until they drop to the ground.

Overall, fall is still a pretty warm season, so summer clothes and a swimsuit will do you just fine and you’ll probably want to have a light jacket or sweater in the evenings for when the temperature drops at night. You’ll also need a raincoat, just in case you get caught in a tropical drizzle or storm.

Yes, although Florida has a much warmer climate, many commonly Florida grown trees do go dormant and completely lose their leaves in the winter months. A couple other tree varieties may “shed” (lose some of their leaves, but not entirely) including: magnolias and live oaks.

Chlorophyll Breaks Down But in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange colors become visible and give the leaves part of their fall splendor.

Scientists say the color change for trees that turn yellow and orange is basically no change at all. The pigments for those colors are always in the leaves, only masked by green chlorophyll used for photosynthesis.

photosynthesis

The answer is a little bit yes and a little bit no. Summer weather won’t do much to influence foliage color. As we said, chlorophyll is still going strong during summer. In fact, in some ways a wet summer would be detrimental to fall leaves – heavy rain or wind could knock leaves off before they have a chance to turn.

Weather plays a role An abundance of sugar and light in the leaf lead to the production of vivid anthocyanin pigments, which produce red, purple and crimson colors.

For each tree species, there is some critical day length during which chlorophyll breakdown begins and other pigments reveal themselves. The clock can also be affected by temperature, elevation, and latitude. An early frost can cause leaves to change colors overnight.

Chlorophyll is also what gives plants their green color. Many people mistakenly believe that weather makes leaves change color. While this is not true, weather can affect how vibrantly the colors appear. If the weather is too hot or cold, the leaves will not be as bright as they begin to change.

The amount and brilliance of the colors that develop in any particular autumn season are related to weather conditions that occur before and during the time the chlorophyll in the leaves is dwindling. Temperature and moisture are the main influences.

Trees use temperature only as a secondary cue; if the fall is cool they hasten the development of their fall color, while if it is warm, they procrastinate and delay it. If global warming results in warmer fall temperatures, either during the day or night, this would tend to delay fall colors to later in the season.

Three factors influence autumn leaf color-leaf pigments, length of night, and weather, but not quite in the way we think. The timing of color change and leaf fall are primarily regulated by the calendar, that is, the increasing length of night.

When daylight hours become less and temperatures are cooler, photosynthesis slows down, and there is less chlorophyll. This decline reveals a yellow or orange pigment, carotenoid. Carotenoids, the same pigment found in carrots and corn, are usually masked by the chlorophyll.

As day length shortens and temperatures cool, hormones within the plant are activated to begin the abscission process. These cells serve to slowly cut the leaf from the plant without leaving an open wound. As the leaves fall, the plant enters dormancy, saving its energy for the great bud burst of spring.

The most common reason that plants’ leaves turn yellow is because of moisture stress, which can be from either over watering or under watering. On the other hand, over watering can contribute to the leaves turning yellow as well.

It’s the time spent between 44 and 30 degrees F, generally through fall to midwinter, that counts. This hints at some yet-to-be-defined biological counting process that grinds to a halt once tissues and cells are below freezing.