In case you were wondering…
Every autumn in Illinois brings with it a breathtaking change of color in the leaves of our trees, but although it’s late September, temperatures have been steadily topping out in the nineties every day. Not a traditional sign of Fall, yet the trees are changing color and dropping leaves as if they were not aware of the hot and humid weather.
Aren’t the leaves supposed to change when it gets cooler and we see some frosts overnight?
Do the trees know what time of year it is despite the unusually warm temperatures?
One explanation, according to Native American myth, is that the hunters in the Heavens killed the Great Bear in autumn and its blood dripped over Earth’s forests coloring some of the leaves red. As the hunters cooked the meat, fat dripped from the Heavens and colored some of the leaves yellow.
Not scientific enough for you? Need a more botanical answer?
In case you were wondering what actually initiates the changing color of the leaves and their eventual fall to the ground, read on…
Most people think that cool weather or frost causes the leaves to change color. It is true that there is usually a correlation between the cooler air and the onset of the autumn show. However, while temperature may impact the color intensity, it has less impact on the timing of the color transitions we see in the Fall than do other factors.
A quick trip back to high school Botany 101. During the spring and summer most of the foods necessary for the tree’s growth are manufactured in the leaves. This food-making process takes place in the numerous cells containing chlorophyll, which gives the leaf its green color. This extraordinary chemical absorbs the energy from sunlight that is used in photosynthesis, the transformation of carbon dioxide and water to carbohydrates, such as sugars and starch.
In late summer or early autumn, the days begin to get shorter, and consequently, the nights are longer. Like most plants, deciduous trees and shrubs are rather sensitive to the length of the dark period each 24-hour cycle. When nights get long enough, the cells of the leaves begin to block transport of materials such as carbohydrates from the leaf to the branch. They also block the flow of minerals from the roots into the leaves. Because the starting time of the whole process is dependent on night length, fall colors appear at about the same time each year in a given location, whether temperatures are cooler or warmer than normal.
The fact is, the vivid yellow and orange colors have actually been there throughout the spring and summer, but we haven’t been able to see them. The deep green color of the chlorophyll, which helps plants absorb life-giving sunlight, hides the other colors. In the fall, fewer hours and less intense daylight prompt the leaves to stop the food-making process. The chlorophyll breaks down, the green color disappears, and the yellow and orange colors already in the leaf become visible again to the human eye. As the trees break down the green pigments and nutrients stored in the leaves they are shuttled into the roots for reuse in the spring.
Along with the green pigment of chlorophyll are carotenoids, yellow to orange pigments, which, for example, give the orange color to a carrot. At the same time other chemical changes may occur which produce red anthocyanin pigments resulting in even more variation in the Fall color scheme. Some mixtures give rise to the reddish and purplish fall colors of trees such as dogwoods and sumacs, while others give the sugar maple its brilliant orange. For most of the growing season these colors are masked by the great amounts of green coloring.
The variations in Fall color are due to the mixing of varying amounts of chlorophyll residue and the other pigments in the leaf combined with a varied response to weather conditions. For instance, as the nights become cooler, the sugars trapped in the leaves of some oaks and maples will often form a red pigment. The degree of color will also vary from tree to tree. Leaves directly exposed to the sun may turn red, while those on the shady side of the same tree or other trees may be yellow.
As the fall colors appear, other changes are taking place. At the point where the stem of the leaf is attached to the tree, a special layer of cells develops and gradually severs the tissues that support the leaf. At the same time, the tree seals the cut, so that when the leaf is finally blown off by the wind or falls from its own weight, it leaves behind a leaf scar. Most of the broad-leaved trees in Illinois shed their leaves in the fall. However, the dead brown leaves of the oaks and a few other species may stay on the tree until growth starts again in the spring.
In general, autumn weather conditions favoring the most brilliant colors are warm sunny days and cool, but not freezing, nights. When there is mainly warm, cloudy and rainy weather in the fall, the leaves may have less red coloration. A few hard frosts can cause the leaves to wither more quickly and drop to the ground.
So, in case you were wondering, with all due respect to the Native American myths, it is a combination of temperature, light, and water supply that have an influence on the onset, the degree, and the duration of fall color.
Enjoy it while you can, because it doesn’t last long!
Most people think of fall as the end of the growing season and the beginning glimpse of another Chicago winter. Well try to look at it as an ideal time to plant!
Fall is a perfect time for planting shrubs, trees, grass seed, and even perennials if they have a developed root system. Fall planting gives plants time to develop roots before winter’s blustery conditions. The conditions are also less stressful and there may be more reliable precipitation.
What happens during fall conditions is a plant’s leaf and flower production is usually slowing down and approaching dormancy. Therefore, a plant can focus on root production. Roots continue to grow when other parts of the plant are not. Generally speaking, root systems will keep growing as long as the soil temperature is at least 50 degrees.
Although we generally get more rain in fall, the good news is that plants use less water then. Because days are increasingly shorter and cooler in the fall, plants are going to be photosynthesizing less and using less water.
Fall is also when depleted nurseries can begin to dig plants again, so varieties that were either unavailable or just downright unsightly in July and August, may become available.
Finally, don’t forget about BULBS! Its often surprising why more people don’t take advantage of this relatively inexpensive way to welcome in Spring. To achieve a gorgeous Spring show bulbs are planted in late fall.
If you’d like to start planning a fall project, it is right around the corner, so call us now and we will be happy to assist you!
During a meeting discussing seasonal color displays, when phones were set on vibrate and the focus of our discussions was solely about plants, I was reminded how passionate and opinionated our staff is when it comes to what they love the most.
I decided it was important to celebrate that our employees each have their favorite species and that those favorites tend to change and evolve. Hence our favorite plant series. First up might as well be me, Donna Vignocchi Zych.
Easy and carefree, ‘Blue Star’ is an outstanding long blooming selection. I look forward to several weeks of deep, glacial blue blooms on this compact, shrubby-like plant. It forms a mound of green, willow-like leaves, bearing clusters of interesting dark blue buds that open into dainty, star-shaped, medium blue flowers from late spring into early summer. The dark green, compact foliage remains attractive all summer and forms the perfect backdrop, for colorful annuals and bold perennials. In fall, the willowy foliage turns a rich shade of yellow complementing my favorite fall blooming perennials: sedum, hardy mums and purpled-leaved heuchera, to name a few.
Light: Full sun to part shade
Growth Habit: Dense, Mound, Shrub-like
Uses: Specimen, edging, or massed in perennial or mixed shrub borders
Problems: No serious insect or disease problems.
Companion Plants: Sedum, Allium, Blue Hosta, Purple-leaved Heucheras
We receive so many questions about our maintenance program, especially from people who are hiring a professional service for the first time. What follows is a detailed account of what it is we do as well as some tips about those extra items that are beneficial to consider. What is included in your maintenance program? Regular weekly maintenance includes:
- Spring cleanup
- Fall cleanup
- Mowing and Line Trimming
- Weeding and debris removal
- Turf Fertilization, Pre and Post Emergent Weed Control Applications
- In-season pruning
- Perennial bed management and rose care
- Annual Flower Design and Installation
- Core aeration
- Seed and Sod Installation
- Mulch and Compost Installation
- Buckthorn Removal
- Small garden design and installation
- Native restoration
Will I receive service each week? You will receive a weekly site visit except during our spring (April) and fall clean up (November) operations. Who is my contact person for Maintenance questions? An Account Manager is assigned to each customer. They are there to answer any questions you may have, solve problems and address issues on your property as they arise. They can also assist in any new ideas for improving the property. Who can I talk to when there is a crew working on my site? Your crew has a crew leader who assures all operations are completed weekly. You may speak with the crew leader or call your account manager should you have questions. Do you collect grass clippings after each mowing? No. Clippings contain water and elements that are desirable for soil and turf. Your soil contains microbes and fungi that break down the clippings to a form usable by the plants. As the clippings decompose, they return organic matter to your soil, helping create tiny spaces (macropores and micropores) for water and air, improving percolation and fighting compaction. What are your pruning practices? Most landscape plants require some form of pruning, whether to preserve a loose, natural form, or to create tight, compact shapes. Each individual tree or shrub has its own, unique pruning needs, depending on variety, exposure and desired result. Unless you have formal hedges or topiaries, our pruning philosophy is to encourage the natural form of the plant. What if it rains on my scheduled maintenance day? In the event of a rain day, we determine if our operations will be harmful to your landscape (i.e. create ruts, tracking of mud, etc.). If we decide we may cause harm then we will not perform maintenance that day and schedule you the following day. Make certain you are signed up for our e-newsletter. We will send out notifications of rain delay. When do you install seasonal color? We offer four possible rotations of annual flowers (or seasonal color): spring, summer, fall and winter. The timing of each installation depends solely on the weather. A rough time line follows: Spring: bulbs late October / early November, spring plantings Late March-Early April Summer: before Memorial Day Fall: September Winter greens: before Thanksgiving Should I core aerate my lawn? Because every lawn is different, that is a question to ask your account manager. Aeration punches deep holes through thatch, turf, and compacted clay soil. Core aerators then deposit these plugs on top of the turf, where they eventually decompose. Over time, this process will de-compact soil, allowing for greater percolation. It also increases the surface area of the turf, encouraging beneficial aerobic bacterial and fungal growth. Why do I need to mulch my beds? Mulch is an organic covering applied to tree and shrub beds. Mulch beautifies your property. Mulch reduces weeds. Mulch retains ground moisture. Mulch protects roots from heat damage. Mulch enriches the soil as it decomposes.
During the growing season, chlorophyll, essential for photosynthesis, is continually being produced and broken down and leaves appear green. As night length increases in the autumn, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids (responsible for orange, yellows and browns in things like bananas and clementines) and anthocyanins (responsible for reds and purples in items like cherries and berries) that are present in the leaf are then unmasked and show their colors.
Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells.
A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays. During these days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions-lots of sugar and lots of light-spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson. Because carotenoids are always present in leaves, the yellow and gold colors remain fairly constant from year to year.
The amount of moisture in the soil also affects autumn colors. A late spring, or a severe summer drought, can delay the onset of fall color by a few weeks. A warm period during fall will also lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights should produce the most brilliant autumn colors.
Some of my favorite places to enjoy the onslaught of fall color? Visit now and often over the next few weeks and watch the marvelous display.
Independence Grove (shown in photo above)
I find it interesting how many sites have so little fall interest. It’s probably because we all kind of forget about our yards starting in September. With the change of seasons comes the change in routine…getting kids back to school, weekends spent watching football, and shorter days mean we spend less time outside.
What I do at this time of year, every year, is spend a lot of thoughtful time watching my garden so that I can plan for next year. I’ve spent all summer watching it evolve, grow and now wane. I want to make sure it is just as beautiful now as it was at its height.
I rely on some old standbys for fall color of course, Viette’s Little Suzy (a new improved version of a black eyed Susan), grasses with their beautiful plumes, fall mums, and Burning Bush and Sumac for that fantastic red color.
But there are some other interesting picks that you might not expect that can give you interest and add to the fundamentals.
Anemone ‘September Charm’