Got Nature? Blog

rainscaping_bannerThe Rainscaping Education Team is offering a free webinar series called Introduction to Rainscaping and Rain Gardens. The four-part series, comprised of one-hour webinars, will take place on April 21, 23, 28 and 30. Registration is full at this time.

“Since we cannot offer in-person spring workshops due to COVID-19, the Rainscaping Education Program’s short webinar series brings you a way to learn more about rainscaping and rain gardens in your own home,” said Kara Salazar, assistant program leader and extension specialist for sustainable communities. “We hope the series inspires attendees to establish rainscaping practices on their landscape. Additionally, we encourage participants to join us when we can offer the next round of in-person workshops to learn more in depth information and also take tours of existing raingardens and participate in the construction of a demonstration rain garden.”

The four-part series will cover topics ranging from an introduction to rainscaping and rain gardens, to site selection, plant selection and installation and maintenance.

Attendees must register two days before the start of the first webinar (April 19) and should plan on attending all four parts of the series. An email containing the access link will be sent to registrants prior to each session.

The full schedule including speakers is below.
rainscape_gardenTuesday, April 21: Introduction to Rainscaping, Rain Gardens and the Purdue Rainscaping Education Program
Noon – 1 p.m. CT / 1-2 p.m. ET
Presenter: John Orick, Purdue Master Gardener State Coordinator

Thursday, April 23: Introduction to Rain Garden Site Selection and Analysis
Noon – 1 p.m. CT / 1-2 p.m. ET
Presenter: Curt Emanuel, Boone County Purdue Extension Educator, County Extension Director

Tuesday, April 28: Introduction to Rain Garden Plant Selection and Design
Noon – 1 p.m. CT / 1-2 p.m. ET
Presenter: Rosie Lerner, Purdue Extension Consumer Horticulture Specialist

Thursday, April 30: Introduction to Installation and Maintenance
Noon – 1 p.m. CT / 1-2 p.m. ET
Presenter: Laura Esman, Managing Director, Indiana Water Resources Research Center and Research Associate & Lab Manager, Natural Resources Social Science Lab

Registration is full. For questions, please contact Kara Salazar, Assistant Program Leader and Extension Specialist for Sustainable Communities, Purdue Extension and Illinois – Indiana Sea Grant at salazark@purdue.edu.

Resources
Rain Gardens Go with the Flow, Indiana Yard and Garden, Purdue Horticulture
Rainscaping Program
Master Gardeners Program
Rainscaping Education Program Highlighted in NOAA Annual Report, Got Nature? Post, Purdue Extension
What is Rainscaping? Purdue Rainscaping Education Program Video, Purdue Extension
Q&A About Drainage Water Recycling for the Midwest,  The Education Store, Purdue Extension resource center
Become a Purdue Master Gardener, The Education Store
Climate Change: How will you manage stormwater runoff?, The Education Store
Plan Today For Tomorrow’s Flood, The Education Store

Kara Salazar, Assistant Program Leader and Extension Specialist for Sustainable Communities
Department of Forestry and Natural Resources


Iron_Clorosis_of_TreesMany trees, shrubs, and other ornamental plantings in Indiana and throughout the Midwest suffer from iron deficiency caused by high pH (alkaline) soil. Soil pH affects plant growth directly and indirectly by affecting the availability of essential nutrients and microbial activity. One of these nutrients is iron, an essential plant nutrient that is required for the production of chlorophyll. Chlorophyll is necessary for photosynthesis and gives plants their green color. Iron (and manganese) deficiency results in leaf yellowing (chlorosis); over time, scorching of foliage, dieback and even death of the tree or shrub can result.

Iron Chlorosis of Trees and Shrubs talks about the symptoms, the cause and the managing of iron chlorosis. One of the authors is Lindsey Purcell, an urban forestry specialist from the Department of Forestry and Natural Resources at Purdue University.

This 5-page publication is part of the Plant Pathology in the Landscape Series and is a free download from the Purdue Extension resource center, The Education Store. View other tree disease publications and video resources as you place keywords in the search field located on The Education Store website.

Resources
Tree Diseases: Oak Wilt in Indiana, The Education Store, Purdue Extension resource center
Tree Diseases: White Pine Decline in Indiana, The Education Store, Purdue Extension resource center
Mechanical Damage to Trees: Mowing and Maintenance Equipment, The Education Store, Purdue Extension resource center
Surface Root Syndrome, The Education Store, Purdue Extension resource center
Tree Appraisal and the Value of Trees, The Education Store, Purdue Extension resource center

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


honeysuckle2

Invasive Asian bush honeysuckle species in spring

honeysuckle

Invasive Asian bush honeysuckle species in spring

The longer daylight period and the warming weather are bringing new life to woodlands. We have a community of native plants, called spring ephemerals, that grow, bloom, and produce seed quickly before the tree leaves emerge and the forest understory is wrapped in shade. Several of my favorite wildflowers are in this group, including hepaticas, trilliums, bloodroot, squirrel-corn, and trout lily.

Some unwelcome invaders also emerge early in the spring, producing early foliage and an unnatural shade competing with our native plants. Several woody invasive plants have moved into our woodlands from ornamental and other plantings and now compete aggressively with our natives. These include Asian bush honeysuckles, privets, winged burning bush, and multiflora rose. These plants tend to produce foliage faster than most of our native trees and shrubs, proving them with a competitive advantage through a longer growing season. This early leaf emergence also provides us with an opportunity to identify these invaders in our woodlands. When walking out to observe the wildflowers or hunt for morels, keep your eyes open for the invasive plants. Small specimens can be pulled when soils are moist. Larger specimens may be cut and the stump treated with a herbicide to prevent sprouting. An easy and effective herbicide to access for landowners is glyphosate concentrate products mixed at a 50% ratio with water. Apply this mixture to the cut stump immediately after cutting. Read the herbicide label to understand the protective gear and application instructions required to apply safely.

If you have a large infestation that is beyond your capacity to control, consider contacting a local forester or other natural resources professional for advice on how best to deal with your invasive plant problem. You may contact the Indiana DNR Division of Forestry for advice from the District Forester.  Private-sector foresters and environmental groups and contractors may also be able to help you manage invasive species on your property. To find a private-sector forester visit www.findindianaforester.org. You can find environmental groups and contractors, and additional information on invasives at the Indiana Invasive Species Council website. Purdue Extension has many invasive species resource publications and videos that can help with identification and management.

Controlling invasive plants can bring a sense of satisfaction, knowing you are doing something to promote the health and sustainability of your property.

To view more Got Nature? posts on Invasive Species:
What are invasive species and why should I care?
Invasive Species: the Good News and the Bad News

Resources
Indiana DNR Division of Forestry
Indiana Invasive Species Council
Report Invasive, Purdue Extension
Invasive Plant Series: Winged Burning Bush, The Education Store, Purdue Extension’s resource center
Burning Bush Video, The Education Store, Purdue Extension’s resource center
What Nurseries Need to Know About the Invasive Species Regulation, The Education Store, Purdue Extension’s resource center
Invasive plants: impact on environment and people, The Education Store, Purdue Extension’s resource center

Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources


Posted on March 19th, 2020 in Forestry, Forests and Street Trees, How To | No Comments »

Purdue Landscape Report: We all have heard about dormancy and the restful time of woody plants in our landscapes. That “chill-out” time is nearing the end and it’s time to think about tree maintenance. Trees and shrubs have actually been growing for quite some time, we just can’t see it… yet. Woody plants begin growth after the chilling requirements have been filled. These requirements are different for every plant. Chilling units are hours of time spent above freezing. The number of hours required for chilling varies for different plants from less than 500 to 1,500 hours or more. Many people think the plant is tracking hours below freezing, but in actuality, hours below freezing has no effect on chilling but does increase cold hardiness. Our mild winter and early spring arrival is playing a role in this process.

Spring-Buds

Figure 1. These oak tree buds may look dormant but have completed their chilling requirement and are ready to break. Source

An important maintenance task is supplemental fertilization during early spring weather, especially if there wasn’t any type of fall fertilization. Let’s take a look at how a tree uses and gains energy during the year to understand why and when trees need good nutrition. After the leaves have fallen there is no way to generate food because without leaves, there is no photosynthesis. There are huge demands on the carbohydrate reserves due to increased metabolic functions to support new leaves, flowers and fruit. Supplemental nutrition can help if storage levels are low or depleted until the new photosynthates are available. That’s a huge demand on its reserves! The tree must rely on stored carbohydrate reserves in its woody parts such as stems and branches to grow. Hopefully, the tree was healthy and developing those reserves going into fall or supplemental nutrition was offered with fall fertilization. If not, then the tree exhausts much of its energy and is in need of new resources.  In some situations, it may be considered safer for the tree to apply fertilizer in the spring. Fall applications, if applied too early in the fall season, can create the risk of forcing the plant into becoming metabolically active right when cold weather hits, creating growth susceptible to freeze damage.

Many woody plants begin the new year’s growth with stored food from the year before. An application of fertilizer in the spring gives an additional boost to this new growth. It is important to note that not all trees and shrubs need fertilization, however, most can benefit from this application, especially the younger actively growing trees. In forests, soils have an abundance of nutrients, but in our landscapes and urban forest areas, that’s not often the case.  As we sweep away leaves, twigs and fallen bark, we’re removing potential recycling of nutrients for the soil. Additionally, the grass around our trees is unnatural and often outcompetes trees for available nutrients and water. That’s why we need to fertilize our trees, spring or fall. Look for signs that your tree is lacking nutrients in the soil. If you see these signs, fertilization may be necessary.

Seasonal-Starch

Figure 2. The graph shows the starch loss or energy used during various growing stages for the tree during the year. Most energy is depleted after leaf emergence and then regained as leaves begin photosynthesizing new resources. Source

  • Shorter than normal annual twig growth
  • Undersized leaves that are fewer in number
  • Dead branches and branch tips
  • Leaf veins darker than leaf margins
  • Leaves any other color than dark green, such as yellow or red

However, never fertilize without getting a soil test. If your trees are experiencing any of the above symptoms, have your local arborist inspect the tree to determine the best treatment. Also, Review Consumer Horticulture: Fertilizing Woody Plants (pdf) for more details on fertilizer application techniques and rates.

Now for just a little about tree pruning. All of that new tree growth is going to prompt the pruning activities… be patient!  Once trees start budding and blooming in the spring hold off until after the flush.  Pruning in the spring can limit bloom potential and remove newly expanding leaves that will be needed to produce new food products for energy.

Generally, the best time to prune is several weeks after the spring flush or during the summer months. Early spring pruning should focus primarily on pruning for safety to remove any dead, dying or decayed branches. Aesthetic or structural pruning can be completed much later and when the tree is better prepared to seal those pruning wounds with energy reserves.  For more information refer to the publication Tree Pruning Essentials from the Education Store on pruning topics.

Resources
Consumer Horticulture: Fertilizing Woody Plants, The Education Store, Purdue University
Tree Planting Part 1: Choosing a Tree, Video, The Education Store
Tree Installation: Process and Practices, The Education Store
Tree Pruning Essentials, Video, The Education Store
Corrective Pruning for Deciduous Trees, The Education Store
Tree Pruning: What Do Trees Think?, The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


Purdue Landscape Report: Yes, we need trees and here’s why…

Trees have presented as more than just a pretty face as research has indicated that trees are even more valuable for their function as much as their form. Currently, more than 50 percent of the world’s population now lives in towns and cities. In the Hoosier state, the last census indicated that 72% of our population lives in an urban area and this statistic is increasing annually.

benefits of trees in downtown area

Properly planted trees improve living conditions in downtown and suburban areas. Sources

For the most part, the rapid expansion of cities takes place with little consideration to land use planning strategy. The resulting human pressure has highly damaging effects on our urban trees and green spaces. The environmental impacts of climate change are intensified by urbanization such as increased pollution, increased temperatures, and larger demands on infrastructure such as stormwater systems.

Urban trees can help to mitigate some of the negative impacts and social consequences of urban sprawl and make cities more resilient to these changes. These important functions are called ecosystem services. This is the way urban foresters measure the benefits that trees provide other than just their beauty. Ecosystems services are the many benefits that trees and plants provide to the community. They improve our quality of life by providing food, cleaner air and water, regulating temperatures, supporting pollination and providing recreational, health and spiritual benefits.

trees benefit health1

People will stay longer and enjoy urban economy more with tree-lined streets. Sources

trees benefit health2

Trees are proven to reduce length of hospital stays and improve birth outcomes. Sources

trees benefits health3

Recreational areas are critical to community well-being. Sources

Here are some easy ways in which urban trees and woodlots contribute to making cities more environmentally sustainable and livable:

  • Trees can contribute to the increase of local food and nutrition security, providing food such as fruits and nuts for wildlife and human consumption.
  • Trees play an important role in increasing urban biodiversity, providing plants and animals with a proper habitat, food and protection.
  • A mature tree can absorb up to 350 lbs. of CO2 per year. As a result, trees play an important role in climate change mitigation. In cities with high levels of pollution, trees can improve air quality making cities healthier places to live in.
  • Strategic placement of trees in cities can help to cool the air between 30-40o F, thus reducing the urban “heat island” effect, helping reduce extreme heat conditions in summer weather.
  • Large trees are great biological filters for urban pollutants and particulate pollution. They absorb pollutant gases (such as carbon monoxide, nitrogen oxides, ozone and Sulphur oxides) and filter fine particulates such as dust, dirt, or smoke out of the air by trapping them on leaves and bark.
  • Research shows that living in close proximity of urban green spaces and having access to them, can improve physical and mental health, for example by decreasing high blood pressure and stress. Also, research indicates greatly improved neo-natal health as well. This, in turn, contributes to the well-being of urban communities.
  • Mature trees regulate water flow and play a key role in preventing floods and reducing the risk of sewer overflow. Stormwater management is a crucial city infrastructure issue and trees help. A mature tree, for instance, can intercept more than 5,000 gallons of water per year and without trees, every rain would contribute floods.
  • Trees also help to reduce carbon emissions by helping to conserve energy. For example, the correct placement of trees around buildings can reduce the need for air conditioning by 30 percent and reduce winter heating bills by 20-50 percent.
  • Planning urban landscapes with trees can increase property value, by up to 15 percent, and attract tourism and business.

These are just a few examples of the functional benefits that trees provide to our everyday life. A community or neighborhood with well-planned and well-managed green infrastructure becomesmore resilient, sustainable and equitable in terms of livelihood improvement, climate change mitigation and adaptation, disaster risk reduction and ecosystems conservation. Throughout their lifetime, trees can thus provide a benefit package worth two to three times more than the investment made in planting and caring for them. Trees aren’t the answer, but they are part of the equation. Planting trees is important, but their maintenance is as equally important.

Trees make life better.

Trees make life better. Sources

For more information on urban tree care, visit the Purdue Education Store for tree care tips and suggestions.

Resources
Tree Appraisal and the Value of Trees, The Education Store, Purdue Extension’s resource center
Tree Pruning Essentials, Publication & Video, The Education Store
Tree Installation: Process and Practices, The Education Store
Tree Selection for the “Un-natural” Environment, The Education Store
The Nature of Teaching: Trees of the Midwest, The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


Rainscaping, planting to help with water runoff.

The Purdue Extension and Illinois-Indiana Sea Grant Rainscaping Education Program was highlighted in the National Oceanic and Atmospheric Administration’s Education Accomplishments Report (pdf) for fiscal year 2019.

This report highlighted all of NOAA’s greatest accomplishments related to education in five main goal areas: science informed society, conservation and stewardship, safety and preparedness, future workforce and organizational excellence.

The Rainscaping Education Program was featured in the Conservation and Stewardship section of the report. The Purdue Rainscaping Education Program offers state-wide training for Purdue Master Gardeners, conservation agencies and organizations, stormwater professionals and landscape companies and consultants. Through two-day workshop sessions, the program provides an introduction to rainscaping and rain gardens, including segments on site selection, plant selection, garden design, installation, maintenance and community engagement.

“It is wonderful to have the innovative and collaborative work of the Purdue Rainscaping Education Team recognized for its efforts,” Kara Salazar, assistant program leader and extension specialist for sustainable communities said. “The team has been working together since 2013 to develop and implement the interdisciplinary program addressing the need for community education on sustainable landscape practices to prevent polluted runoff.”

Salazar and John Orick, Purdue Master Gardener State Coordinator, are co-leads on the project. View  the full Rainscaping Team.

The featured segment on the Rainscaping program from the NOAA annual report is below.
2019 NOAA annual report highlighting Purdue Extension Rainscaping.

Resources
What is Rainscaping? Purdue Rainscaping Education Program Video, Purdue Extension
Q&A About Drainage Water Recycling for the Midwest,  The Education Store, Purdue Extension resource center
Become a Purdue Master Gardener, The Education Store
Climate Change: How will you manage stormwater runoff?, The Education Store
Plan Today For Tomorrow’s Flood, The Education Store

Kara Salazar, Assistant Program Leader and Extension Specialist for Sustainable Communities
Department of Forestry and Natural Resources


TreeTrees provide many benefits and value to property owners in functional, aesthetic, social, environmental, and even economic ways. Functional benefits include mitigating climate change by storing carbon, removing pollution from the atmosphere, managing stormwater runoff, and improving air quality. Trees provide oxygen and many other benefits – such as shade, which can impact home cooling costs.

The collective value of trees makes a difference in people’s health and quality of life in cities and towns everywhere. This updated Purdue Extension publication Tree Appraisal and the Value of Trees describes methods used to appraise trees and landscapes that can determine their value and worth, reasons why a tree should be appraised, the factors that go into tree appraisal, what appraisal ratings mean, and sample scenarios.

Resources
The Nature of Teaching: Trees of the Midwest, The Education Store, Purdue Education Resource Center
Corrective Pruning for Deciduous Trees, The Education Store
Resources and Assistance Available for Planting Hardwood Seedlings, The Education Store
Tree Support Systems, The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


surface rootTrees in the landscape are highly prized and provide many benefits to you and your home. However, those shallow roots that appear on the surface of our lawns can create real headaches, especially when trying to grow lush turfgrass. This free download Surface Root Syndrome publication will help you learn what surface roots are, common approaches to address the problem, and best practices to management.

Resources
Tree Appraisal and the Value of Trees, The Education Store, Purdue Extension resource center
Tree Support System, The Education Store
Tree Diseases: White Pine Decline in Indiana, The Education Store
Tree Diseases: Oak Wilt in Indiana, The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


Expensive and complex equipment is often needed around homes.

Purdue Landscape Report: There are many different aspects of tree work which include a wide range of costs, but let’s start with the most common expense: tree removal. It can be difficult to understand why removing a tree can cost so much when the whole process seems as simple as “just cutting it down.” In reality, the work is usually much more involved than making a few cuts with a chain saw and then hauling it all away.

Complexity – Trees being removed often need to be cut apart in sections to avoid dropping the whole tree or large pieces onto the lawn or landscape or into the street. This is a safer approach and also prevents serious damage to the turf and landscape below. News reports are full of accidents involving untrained tree workers, or homeowners, attempting to cut down a tree without the knowledge of how the tree reacts to being cut. Usually, specialized equipment is needed, such as aerial lifts or cranes to access the tree safely. This equipment is costly to acquire and maintain. Some of the typical equipment such as these mentioned can cost more than some homes! Often, the use of this equipment involves setting up traffic control in busy streets where permits and additional flagging support are needed.

Difficult and dangerousTree work requires training and expertise for safe pruning and removals.Tree pruning and tree removal, is difficult and dangerous work. Also, there is a reason why the tree is being removed. Often it has been deemed high risk or presents a danger on the site. Tree crews are regularly asked to work on trees with compromised structure from storm damage or years of neglect. These compromised trees are often dead trees, which are particularly dangerous. A tree that has been dead for several years usually becomes brittle and inflexible. When you try to cut it down, controlling the direction of fall is a challenge and it will often shatter, throwing broken branches in an uncontrolled manner. Often, tree workers are in trees that have electrical conductors running through the branches. That risky situation should speak for itself.

Insurance, Licensing – Because tree work can be hazardous, qualified companies will have expensive liability insurance to protect the homeowner’s property, as well as workers’ compensation insurance to help cover injuries sustained by the crew, should they occur. You get what you pay for and this includes tree care as well! If you select a company that is less expensive, they may not carry insurance which leaves the tree owner at a high risk of having to pay damages several times the original job estimate, if something goes wrong. Always check with your tree care company to be sure they can validate proper insurance before starting tree work. This applies to any service company which may be used in and around your home or property.

Trained and Certified Workers – Its best to choose a tree care company where the crew has current industry credentials Large cranes may be required to safely remove the tree.and a history of training and experience. How do you know if a company’s staff is trained and experienced? Ask to see their credentials and look for programs such as the International Society of Arboriculture (ISA) Certified Arborist, or the Tree Care Industry Association (TCIA) Certified Treecare Safety Professional which are indicators of a professional business with the expertise to perform the work. Tree owners and managers have the option to interview two or three tree care companies before deciding about tree removal or other critical practices such as pruning. Ask to see a copy of the current insurance certificate as well as copies of the crew’s competency credentials. If a company representative hesitates to provide these documents or insists, they don’t need to “prove” themselves, find another company to perform the work. Ask for references. This is easy since often all that is needed is to drive by a location to see the quality of the pruning work or removal work completed.
Certified Arborists can provide the best care for your trees.
Find a professional – Also, to check for an ISA Certified Arborist in your area, visit the website www.treesaregood.org then click on the link “Find an Arborist”. By entering your zip code, a list of credentialed arborists can be found nearest your location.

Tree care performed properly will be an investment in your property that, when done correctly, will give you valued returns for decades.

Resources
Mechanical Damage to Trees: Mowing and Maintenance Equipment, The Education Store, Purdue Extension resource center
Tree Appraisal and the Value of Trees, The Educational Store
Tree Pruning Essentials, video, The Education Store
Tree Pruning Essentials, The Education Store
Tree Selection for the “Un-natural” Environment, The Education Store

Lindsey Purcell, Urban Forest Specialist
Purdue University Department of Forestry and Natural Resources


Purdue Landscape Report: Just as sure as you try to predict the weather, it is likely to change. But going out on a limb, I predict that we will have a bit of a dud for fall color display this year. Not a very risky prediction, considering that many plants already are starting to turn color and/or drop leaves in some areas of the state.

Nyssa sylvatica

Nyssa sylvatica (black gum) showing early fall color due to drought stress. Source

So why would the colors be early and/or a bit duller than usual? Certainly, some of the reason why plants display fall colors has to do with the genetic makeup of the plant. That doesn’t change from year to year. But the timing and intensity of fall colors do vary, depending on factors such as availability of soil moisture and plant nutrients, as well as environmental signals such as temperature, sunlight, length of day, and cool nighttime temperatures.

The droughty conditions experienced during much of the second half of summer are likely to have decreased the amount of fall color pigment. Southern Indiana has been particularly parched. Despite recent rains in some areas, much of the state remains designated as abnormally dry to moderate drought. You can check your area’s conditions at the US Drought Monitor for Indiana. Additional maps and data is available at the Midwest Regional Climate Center.

Growing conditions throughout the season affect fall color as does current weather. Colors such as orange and yellow, which we see in the fall, are actually present in the leaf all summer. However, those colors are masked by the presence of chlorophyll, the substance responsible for green color in plants during the summer. Chlorophyll allows the plant to use sunlight and carbon dioxide from the air to produce carbohydrates (sugars and starch). Trees continually replenish their supply of chlorophyll during the growing season.

As the days grow shorter and (usually) temperatures cooler, the trees use chlorophyll faster than they can replace it. The green color fades as the level of chlorophyll decreases, allowing the other colored pigments to show through. Plants that are under stress–from conditions like prolonged dry spells–often will display early fall color because they are unable to produce as much chlorophyll.

Yellow, brown and orange colors, common to such trees as birch, some maples, hickory and aspen, come from pigments called carotenoids, the same pigments that are responsible for the color of carrots, corn and bananas.

Red and purple colors common to sweet gum, dogwoods and some maples and oaks are produced by another type of pigment called anthocyanin, the pigment responsible for the color of cherries, grapes, apples and blueberries. Unlike chlorophyll and carotenoids, anthocyanins are not always present in the leaf but are produced in late summer when environmental signals occur. Anthocyanins also combine with carotenoids to produce the fiery red, orange, and bronze colors found in sumac, oaks, and dogwoods.

Red colors tend to be most intense when days are warm and sunny, but nights are cool–below 45º F. The color intensifies because more sugars are produced during warm, sunny days; cool night temperatures cause the sugars to remain in the leaves. Pigments are formed from these sugars, so the more sugar in the leaf, the more pigment, and, thus, more intense colors. Warm, rainy fall weather decreases the amount of sugar and pigment production. Warm nights cause what sugars that are made to move out of the leaves, so that leaf colors are muted.

Leaf color also can vary from tree to tree and even from one side of a tree to another. Leaves that are more exposed to the sun tend to show more red coloration while those in the shade turn yellow. Stress such as drought, poor fertility, disease or insects may cause fall color to come on earlier, but usually results in less intense coloration, too. And stress or an abrupt hard freeze can cause leaves to drop before they have a chance to change color.

So far, weather conditions lead me to think this will be one of those not so showy fall color years. I hope I am proven wrong!

Resources
Why do leaves change color and why do leaves fall off in autumn?, Got Nature? Blog
Why Leaves Change Color, The Education Store, Purdue Extension
Fifty Trees of the Midwest App for the iPhone, The Education Store
Native Trees of the Midwest, The Education Store
Why Leaves Change Color, USDA Forest Service, Northeastern Area
It’s Fall, but why are the leaves still green? article and video, WLFI.com

B. Rosie Lerner, Extension Consumer Horticulturist
Purdue Horticulture and Landscape Architecture


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