Got Nature? Blog

Purdue Landscape Report: Spotted lanternfly (SLF) has been the subject of a lot of media attention in the last few years.  In the east, states like Pennsylvania and New York have been dealing with heavy infestations since the insect was first detected in 2014.  In Indiana, this invasive planthopper arrived three years ago, infesting two counties on the eastern side of the state.  Since then, the Indiana Department of Natural Resources and Purdue University have been working together to mitigate the spread of this insect as well as educate Hoosiers on what they can do to help.  Spotted lanternfly is still on the move, and this update will help refresh you on how this bug works, and where they are headed.

Life cycle
Spotted lanternfly is an annual insect, having only a single generation in a year under normal conditions.  The insect goes through incomplete metamorphosis; immature stages, called nymphs, resemble smaller, wingless versions of the adults.  Nymphs will begin to appear in April or May, developing through four instars, until they reach adulthood in late summer.  With each instar, the period in between molting, the nymph will grow larger, develop wingpads, and eventually change color.  Early instars are black with a white dot pattern, while later instars will be bright red with black and white patterning (Fig. 1).  Late instar nymphs are often compared to milkweed bugs or lady beetles.  Once they complete development in the late summer or early fall, they will mate and lay egg masses covered in a protective substance that makes them resemble mud.  Eggs masses will overwinter until the spring, while adult insects will die as temperatures cool.  In Indiana, depending on temperature, adults can be seen as late as early November.

Impact
Spotted lanternfly is a sap-feeding insect, using syringe-like mouthparts to drain nutrients directly from plant tissues.  Like other sap-feeding insects, the activity of SLF wounds the plant, creating openings for various pathogens to exploit.  Feeding by SLF has been shown to reduce overall health of their hosts, reducing their capacity to survive overwintering, and potentially kill the host plant depending on species.  They also produce a sugary waste known as honeydew; while honeydew itself is not harmful, it acts as a growing substrate for sooty mold, which can have a serious impact the photosynthesis of understory foliage as well as attract other nuisance insects.

Spotted lanternfly is a generalist herbivore and can feed on over 100 different species of plant and tree in Indiana.  However, this insect has shown strong preference towards certain species, often with devastating consequences.  The most preferred host is tree-of-heaven, an invasive tree species in North America.  Tree-of-heaven is the primary host of SLF in their shared native range, and the insect appears to experience high reproductive success on it even when they share a new environment.  Grapes are also highly preferred by SLF, and infestations will typically result in overfeeding and the death of the plant.  Black Walnut, American river birch, and various maple species are also at risk of severe damage from this insect.   Evidence has also suggested that maple, when used for syrup production, will experience reductions in yield and quality when attack by spotted lanternfly.

Where are they now?
Spotted lanternfly has been present in Indiana since 2021, first arriving in Huntington and Switzerland Counties.  In Huntington, the infestation occupies a stand of tree-of-heaven next to an industrial parking lot.  Tree-of-heaven moved into the neighboring residential area, allowing SLF to also spread with it. The more rural infestation in Switzerland County was traced to a vehicle transported from Pennsylvania, and the insect has taken advantage of patches of tree-of-heaven in nearby wooded areas.  While both infestations have strongly associated with the insect’s primary host, there is some evidence that SLF is beginning to take advantage of other nearby plants, such as maple.  In the last year, SLF moved a significant distance and has been detected in several more counties, including Elkhart, St. Joseph, Porter, Allen, Dekalb, and Noble Counties.  Most of the activity has been found on tree-of-heaven along rail lines, supporting the idea that the insect is dispersed by rail traffic moving westward out of infested areas.

It’s important to remember that trains aren’t the only vehicles that can have SLF passengers.  These insects, and their egg masses, can be found on just about any surface, including the car you drive to work, the RV you used for recreation, semi-trucks that cross the country, and more.  Purdue Entomology and Indiana DNR are encouraging everyone to inspect their vehicles when traveling through any of the infested areas.  Also check all recreational vehicles and trailers for spotted lanternfly egg masses; if found, scrape them off into a bag or bucket filled with soapy water.  This fall and winter, we also want to encourage everyone to please burn any firewood where you buy it, and please don’t move it off your property if you chop it yourself- especially if you are burning tree of heaven.  Egg masses will stick to firewood and can survive our winters very well.

What can I do?
We are still learning about the spotted lanternfly’s distribution through Indiana, and we need the help of citizen scientists to effectively track the insect’s movement.  If you believe you’ve seen spotted lanternfly, please report it using any of the resources listed below.  You can also feel free to reach out to Bob Bruner, Exotic Forest Pest Educator, by emailing them at rfbruner@purdue.edu, or you can report sightings by calling 1-866-NOEXOTIC.

Original article posted: Spotted Lanternfly is on the Move!.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Spotted Lanternfly Resources:
Spotted Lanternfly Found in Indiana, Indiana Woodland Steward
Spotted Lanternfly Feeds on Over 70 Plus Plant Species, Purdue Extension – Forestry and Natural Resources (FNR)
Spotted Lanternfly – includes map with locations, Indiana Department of Natural Resources Entomology
Spotted Lanternfly is on the Move!, Purde Landscape Report
Spotted Lanternfly Egg Hatch is Here, Purdue Landscape Report
Report Spotted Lanternfly, Purdue College of Agriculture Invasive Species

Other Resources Available:
Invasive plants: impact on environment and people, The Education Store, Purdue Extension’s resource center
Woodland Management Moment: Invasive Species Control Process, Video, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Invasive Species, Playlist, Purdue Extension – FNR YouTube Channel
What are invasive species and why should I care?, Got Nature? Blog, Purdue Extension – FNR
Report Invasive, Purdue College of Agriculture – Entomology
ReportINvasive, Purdue Report Invasive Facebook posts include webinars and workshops

Bob Bruner, Exotic Forest Pest Educator
Purdue Entomology

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Purdue Landscape Report: By now, the emerald ash borer (EAB) invasion is an old story for landscapes and forests in the Midwest. Since EAB was first found in North America in 2002 more millions of ash trees than we can know have died and this tiny insect continues to kill ash in an ever widening zone that currently includes 37 US states and 6 Canadian provinces. Arborists and landscape managers continue to protect valuable ash trees by use of systemic insecticides, typically applied via trunk injection every 2-3 years.

While EAB is the overarching threat, ash survival may also be threatened by wood decay fungi, which may colonize insect exit holes, injections sites and other wounds. The most common decay fungi we see in the lab are Perenniporia and Fomitopsis.

Perenniporia fraxinophila is the most frequently reported wood decay fungus on ash and causes a heart rot that contributes to loss of structural integrity of the tree. Infection sites tend to be high on the tree and may be easily overlooked until decay is advanced. The fungal structure is perennial, expanding each year, and may be confused with Ganoderma applanatum, the artist’s conk. The upper surface turns black or brown with age and the underside is white with pores instead of gills.

 

In the last few years, we have had a few samples of a similar fungus colonizing the trunk and base of ash trees, often near injection sites. Initially we were unable to identify the fungus, but DNA analysis revealed the fungus was a Fomitopsis species. This fungus develops a shallow shelf structure with white top and tan underside.

Fungal decay presents a greater risk to ash because it lacks the preservative enriched heartwood found in oak, walnut and other hardwoods that tends to slow down internal spread of fungi. Even fungi that initially invade dead areas of ash may rapidly colonize and degrade stem and trunk tissue.

 

Fungal decay also disrupts vascular tissues in the stems and trunk, which further limits the movement and effectiveness of insecticide injections, so that infected trees may face greater damage from EAB. When found on small side branches the infection might be successfully pruned out, but in most cases the decay is in major branches or the trunk, which means the tree will need to be removed. If your ash trees that are being regularly treated for EAB but continue to show thinning and decline, check for these fungal invaders, they may be partly responsible.

View the original article on the Purdue Landscape Report website: Fungal Decay of Ash Trees.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
Diplodia Tip Blight of Two-Needle Pines, The Education Store, Purdue Extension resource center
Boxwood Blight, The Education Store
Disease of Landscape Plants: Cedar Apple and Related Rusts on Landscape Plants, The Education Store
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension – Forestry & Natural Resources (FNR) YouTube Channel
Tree Planting Part 2: Planting a Tree, Purdue Extension – FNR YouTube Channel
Find a Certified Arborist, Trees are Good-International Society of Arboriculture (ISA)
Video: Step by Step to Find an Arborist, Trees are Good-International Society of Arboriculture (ISA)
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
Tree Pruning Essentials, Publication & Video, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – FNR
What are Invasives Species and Why Should I Care?, Got Nature? Blog, Purdue Extension – FNR
Subscribe – Purdue Extension-FNR YouTube Channel

Tom Creswell, Plant & Pest Diagnostic Laboratory Director
Purdue Botany and Plant Pathology

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Purdue Landscape Report: It’s finally October, and we should be enjoying lovely fall temps and colors. While some of the trees are changing, it’s not necessarily due to the change in seasons. As I write this, the temperature is 84 F (29 C). I look out my window and see mostly green leaves with some colors from the short cold snap we had and some from heat and drought stress. Whether you are worried about the trees in your yard and community or not, there are some simple tasks that we can do to assist them as we await the cooler temperatures of Autumn.

Mulching: One simple task to better prepare your trees for winter is to add a new layer of mulch, which benefits your trees in multiple ways. Adding a 2-3 inch thick layer of mulch will better maintain moisture levels and buffer extreme temperature changes in the soil and will add some organic matter too. Mulching to the drip line will benefit the tree the most, but in the case of larger trees it’s not always feasible. Try for at least a 3-foot radius from the trunk and make sure to leave a 2 inch or so gap between the trunk and the mulch. Remember, no volcano mulching.

Fertilizing: That mulch you just added will add some organic material to your soil as it slowly breaks down, but an autumn fertilization can benefit your trees too. Unlike trees in the forest that have a natural supply of nutrients from fallen leaves and twigs, trees around our homes are usually deprived as we rake and clean up our yards. Adding a slow-release fertilizer in the fall helps provide a nutrient boost over the winter, can promote root growth, and better prepare your tree for Spring.

Watering: Water is still an essential part of your tree care plan, but as temperatures drop and trees begin to head into dormancy they don’t need as much water as is required in the hit summer months. If you have irrigation systems in your yard start to drop the frequency of watering. You can water up until the first freeze, but make sure soils are just a little damp and not soaked. Evergreens in particular will benefit from slow deep watering 1-2 times a week until the soil freezes. Winter winds and temperatures can desiccate the needles without an adequate supply of water.

Pruning: Now is a good time to prune out any dead, damaged, or diseased limbs in your trees. If you have access to hand saws and pole saws or pruners, you can remove smaller branches or those closer to the ground. Make sure you are making proper pruning cuts though, and if there are large limbs, those at heights, or you are just unsure of how to make a good cut enlist the help of a professional arborist.

Trunk Damage: Sunscald or southwest damage occurs on young and/or thin barked trees in the winter. Wounds can occur between the south to southwest facing part of the trunk on sunny days in the winter as temperatures rise and suddenly drop. Over time these wounds can become quite large. Trees can also incur damage from deer during the rut. Bucks will scrape trees with their antlers, scraping off the bark and damaging the cambium. Both of these injuries can be reduced one younger trees by installing tree guards in the fall. Tree guards are plastic barriers you place around the main stem of the tree. I recommend using white corrugated drainage pipe that can be found at most home centers. You can make a cut lengthwise along the pipe for easy installation and make sure it has a large enough diameter to leave a space between it and the tree. Just remember to remove it come Spring.

Inspections: Visual inspections can be done year-round, but this time of the year it might be easier to see changes in your tree as leaves are falling and the canopy becomes more visible. From the ground up to the canopy, some of the things you’re looking for include fungal growth around the base of the tree, any sort of damage on the main stem or branches, premature leaf drop or color change, and branches that are dead, cracked, diseased, or seem weak. Any concerns you find are also great information to share with an ISA Certified arborist which can be found using the Trees Are Good website.

View the original article on the Purdue Landscape Report website: Help Your Trees Transition into Autumn.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
Re-mulch Your Trees, Purdue Landscape Report
Find an Arborist video, Trees are Good-International Society of Arboriculture (ISA)
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Moist soil and rotten roots makes it easy for trees to come crashing down – Fox 59 News
Expert: Some storm damage can be easily prevented – Fox 59
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
Tree Pruning Essentials, Publication & Video, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment – The Education Store
Trees and Electric Lines – The Education Store
Tree Defect Identification, The Education Store
Planting Your Tree, video, Purdue Extension
Tree Installation, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Subscribe – Purdue Extension-FNR YouTube Channel

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

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Purdue Landscape Report: Aspen, cottonwood, and poplar are all names for the fast-growing Populus tree species. Used widely for building materials, these trees are often located around ponds, riverbanks, and sloping areas toward water bodies (especially cottonwood). Cottonwood flowers produce little white tufted seeds that float through the air which a lot of people love (my kids included), unless it lands in their mouth. These beautiful trees are susceptible to a fungus that can cause significant damage under the right conditions: Marssonina (newer name is Drepanopeziza).

There are three species of Marssonina that can infect Populus – different tree species may only be susceptible to one of the Marssonina species. The fungi cause the same kind of disease and develop similarly on the host. Marssonina can infect the leaves, stems and seeds of Populus, which can lead to large amounts of leaf loss during wet weather, girdled stems and dieback, and aborted seeds. Since seeds can carry the fungus, the seed will take it with it to where it lands and can become infected immediately after germinating. It is common to see high disease severity in the canopy, but unless there is significant leaf loss (up to 70% defoliation) it may not reduce plant vigor. Leaf lesions typically develop as small black to brown dots or flecks which expand in size as time goes one. As the disease progresses, large areas of the leaf will become necrotic, creating odd dead blotches, potentially killing the majority of the leaf blade.

The fungus produces asexual spores in a small black pustule on the upper surface of the leaf which will eventually burst and release the spores during humid weather early in the spring. Marssonina will continue to produce spores and cause disease the whole season, creating repeat infections on the same tree. Symptoms tend to start lower in the canopy and ascend up the tree as the season progresses. The spores are spread by water splash, so rainfall will help spread this fungus in the landscape.

For trees planted in native landscapes, this disease will likely be inevitable and may make the foliage look less than stellar. That being said, removing leaves that drop or at the end of fall will reduce total inoculum for future seasons and can reduce total disease long-term. Similarly, trees that are stressed will typically develop increased disease severity, so if you are seeing large amounts of leaf spots or leaf loss, I would recommend employing stress mitigation strategies to keep the tree happy and healthy (fertilizer, mulch, irrigation as needed, etc.). If a tree appears to develop significant disease every year and has reduced limb growth, you may consider removing the tree if you are concerned it may die early and replace with a resistant clone, as disease susceptibility can vary greatly between clones of the same species.

View the original article on the Purdue Landscape Report website: Marssonina leaf spot and blotch of Poplar.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
ID That Tree, Playlist, Purdue Extension – FNR YouTube Channel (Invasive White Mulberry, Siberian Elm, Tree of Heaven)
Eastern Cottonwood, Article, Purdue Fort Wayne
Find a Certified Arborist, Trees are Good-International Society of Arboriculture (ISA)
Video: Step by Step to Find an Arborist, Trees are Good-International Society of Arboriculture (ISA)
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
Tree Pruning Essentials, Publication & Video, The Education Store
Tree Defect Identification, The Education Store
Planting Your Tree, video, Purdue Extension
Tree Installation, The Education Store
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel (Against Invasives, Garlic Mustard, Autumn Olive)
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel (Common Buckthorn, Japanese Barberry)
Indiana Invasive Species Council
Indiana Department of Natural Resources: Invasive Species
Subscribe – Purdue Extension-FNR YouTube Channel

John Bonkowski, Lead Extension Administrator
Purdue Department of Botany and Plant Pathology

 

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Purdue University Landscape Report: Early fall is the time to begin preparing trees for the winter and get them off to a good start in the following spring. Preventative maintenance and some good cultural practices in autumn boost trees’ health and vigor during the winter and creates an encouraging growing environment in the spring. Here are 5 good tips for trees:

1. Scout for pruning issues.
   It’s advantageous to schedule pruning tasks after leaves have fallen. It’s much easier to see the branch structure of trees and deciduous shrubs in order to perform good selective cuts. Look for those non-beneficial plant parts and remove them. These include any dead, broken and crossing branches which can be removed. Also, search out and remove those epicormics sprouts in the canopy and basal sprouts emerging from around the trunk and root collar.  Refer to this pruning publication for more information.
   

   Newly-established trees benefit from fertilizer

2. Feeding for the future.
   Typically, tree roots have produce more root growth during the fall. Root systems are important as storage organs or banks to reserve energy for later. These stores of starch will become active energy on demand in the spring when shoot growth, leafing and flowering occur. Fertilization during this time will maintain soil nutrient levels and increase root production, promoting new growth in the spring. Newly, established trees and those younger trees are especially responsive to supplemental feeding. However, not all trees need or require fertilization. Refer to this publication on fertilization for more information.
   

   Mulch provides a blanket of protection

3. Complete cultural practices.
   It’s always beneficial to the tree to replenish mulch to give root systems an extra layer of protection against temperature extremes. This helps maintain the moisture levels in the soil during those drier winter months as well. Maintaining 2-3 inches of composted mulch over the root zone of the tree and landscape provides great protection. Also, it may be a good time to consider providing protective wraps on thin-barked or newly planted trees, if needed. Also, now is a good time for inspecting those existing wraps to be sure they are effective and not too tight around the trunk or harboring hidden pest issues.
   

   Good moisture levels going into the winter is critical for tree health

4. Water needed, still.
   The dry, cool air and low precipitation that can sometimes occur during fall and early winter can take a toll on trees. Provide supplemental irrigation with deep watering to prevent root damage and a good spring start. It is advisable to water only when temperatures will be above 40^o Water around mid-day so there is time to soak in before the freezing night temperatures. Applying approximately 5 gallons water per inch of tree diameter will be adequate for times when there is little to no rainfall going into winter.
5. Take inventory.
   This is a good time to assess your site for vacancies. Check your property for potential planting locations to install new trees next spring. Research during the winter allows plenty of time for good decision-making which includes proper species selection and suitable locations. Refer to the tree selection publication for more information.

There are many resources available to learn about proper tree care. If you are uncertain on how to maintain your trees or prefer professional services, it is important to reach out to an ISA Certified Arborist to help with the tree, within your landscape, especially the larger, mature trees. A Certified Arborist can proactively identify, analyze and evaluate your tree needs to maintain this important asset, your trees.

Resources:
Why Do Our Trees Go From Green Leaves to Different Colors?, Got Nature? Blog
Fifty Common Trees of Indiana
An Introduction to Trees of Indiana
The Nature of Teaching: Trees of the Midwest, The Education Store
Why Leaves Change Color, USDA Forest Service

Lindsey Purcell, Executive Director
Indiana Arborist Association

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Welcome to ID That Tree! In this episode, Purdue Extension Forester Lenny Farlee introduces us to a striking native shrub known as Wild Hydrangea. Found in forest understories and along wooded slopes in southern Indiana, this plant is especially noticeable in summer thanks to its large, white flowers. Learn how to identify this species by it’s unique characteristics. Whether you’re a student, hiker, gardener or just curious about native plants, this video offers a quick and informative look at how to spot Wild Hydrangea and appreciate its role in Indiana’s woodland ecosystems.

 

If you have any questions regarding wildlife, trees, forest management, wood products, natural resource planning or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

Resources:
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Fifty Common Trees of Indiana, Purdue Extension – FNR
Habitat University, Episode 12 – Exploring the challenges of Invasive Species, Habitat University-Natural Resource University
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Native Trees of the Midwest, Purdue University Press
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Find an Arborist, International Society of Arboriculture
Forest Improvement Handbook, The Education Store

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

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The Wisconsin Forestry Center at the University of Wisconsin–Stevens Point has just released a new episode of SilviCast, the go-to podcast for silviculture professionals. In this episode, titled “Black Gold,” forestry expert Lenny Farlee is interviewed about the science and management of black walnut, one of North America’s most valuable hardwoods.

Eastern black walnut is often regarded as one of the most valuable timber species in central and eastern North America. A single high-quality tree can be worth thousands of dollars, sometimes even shaping the outcome of an entire timber sale. Given that level of interest, it may seem like we already know everything about this remarkable species. While researchers and foresters have gained a deep understanding of its silviculture and genetics, there is still more to discover.

Lenny Farlee is a Purdue University Extension Forester and a member of the Hardwood Tree Improvement & Regeneration Center (HTIRC). With decades of experience in hardwood silviculture, he brings practical insight and research-based knowledge to the conversation around managing black walnut for long-term forest health and productivity.

To listen, search SilviCast on your favorite podcast app or listen directly on the SilviCast: Black Gold episode page. You can also explore the full series at linktr.ee/SilviCast.

Other Resources:
ID That Tree: Black Walnut
Hardwoods of the Central Midwest: Black Walnut
Hardwood Lumber and Veneer Series: Black Walnut
Morton Arboretum: Black walnut
Facts About Black Walnut, The Education Store
Purdue Arboretum Explorer
Black Walnut, Native Trees of Indiana River Walk, Purdue Fort Wayne
The Woody Plant Seed Manual, U.S. Forest Service
Fifty Common Trees of Indiana
An Introduction to Trees of Indiana
Native Trees of the Midwest, Purdue University Press
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Investing in Indiana Woodlands, The Education Store
Forest Improvement Handbook, The Education Store
ID That Tree, Purdue Extension-Forestry & Natural Resources (FNR) YouTube playlist
Woodland Management Moment , Purdue Extension-FNR YouTube playlist

University of Wisconsin-Stevens Point

Diana Evans, Extension & Web Communications Specialist
Purdue University Department of Forestry and Natural Resources

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With rainfall well below average, watering your trees is more important than ever. Indiana typically receives around 3.14 inches of rain in September, but as of 2025, only 1.31 inches have fallen—making this month even drier than last year. These conditions can lead to dry, wilted leaves and stress for trees across the state, especially during prolonged heat. To see how drought is affecting your area, visit the U.S. Drought Monitor for Indiana-specific maps.

In this video, Lindsey Purcell, Executive Director of the Indiana Arborist Association, explains why consistent watering is critical and shares practical tips to help your trees stay healthy through dry spells.

Extreme heat can have a major impact on tree health and survival. Water is the most limiting ecological resource for a tree, and without adequate moisture, decline and death are imminent. It reduces carbohydrate production, significantly lowering energy reserves and production of defense chemicals in the tree. Check out this publication titled Drought? Don’t Forget the Trees! to learn what to look for for any weakening issues including pests that like the dry conditions.

If you have any questions regarding wildlife, trees, forest management, wood products, natural resource planning or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

More Extreme Heat Resources:
Climate and Drought Maps, Purdue Indiana State Climate Office
Summer Tree Care, Purdue Landscape Report
Drought? Don’t Forget the Trees!, The Education Store, Purdue Extension resource center
Extreme Heat Including Fact Sheets, Purdue Extension – IN-PREPared
Extreme Heat – Resources, Extension Disaster Education Network (EDEN)
Drought Information​, Indiana Department of Natural Resources
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension YouTube Channel
Tree Selection for the “Un-natural” Environment, The Education Store
Tree Pruning Essentials Video, Purdue Extension YouTube Channel
Tree Defect Identification, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Surface Root Syndrome, The Education Store
Submit Sample, Purdue Plant & Pest Diagnostic Lab
Find an Arborist, Indiana Arborist Association

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

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Welcome to ID That Tree! In this episode, Purdue Extension Forester Lenny Farlee introduces us to a relatively common Indiana shrub called Witch-Hazel. Discover the characteristics of the environment this shrub is found in, the features of the shrub itself and the interesting history behind it! As a nature lover, student or someone who’s simply just curious about local plants, this video is a great way to get a quick run-down on important information and identification.

If you have any questions regarding wildlife, trees, forest management, wood products, natural resource planning or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

Resources:
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Fifty Common Trees of Indiana, Purdue Extension – FNR
Habitat University, Episode 12 – Exploring the challenges of Invasive Species, Habitat University-Natural Resource University
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Native Trees of the Midwest, Purdue University Press
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Find an Arborist, International Society of Arboriculture
Forest Improvement Handbook, The Education Store

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

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Purdue Landscape Report: Tree care, in many cases, can be expensive if you require the assistance of an arborist for pruning or removals.  Extreme weather events, characterized by extensive rain and wind, can cause damage to the canopy or, in worst-case scenarios, lead to tree failure.  In cases of failures, weather is often the final push to already existing issues.  One cause that can lead to decay, decline, and failure if applied incorrectly can also extend the life of your tree with proper application.

Mulch is the double-edged sword that can promote healthy growth by maintaining soil moisture and temperature through extreme heat, cold, and drought, enrich the soil in the critical root zone, maintain a safety area from mechanical damage from lawn care tools, and add a nice aesthetic.

But it can also cause decay through excess moisture to the root flare, damage from pests like mice and insects that can live in mulch, expose the tree to pathogens, and promote unnecessary root growth and/or stem girdling roots that cut off nutrient supply between the root system and the rest of the tree.

The application is the same if it’s the first time mulching a tree or a re-application.  Add enough mulch so there is a 2–3-inch layer sloping away from the tree with at least a 3–5-foot radius around the stem (older, larger trees can benefit from larger mulch rings).  No volcano mulching, make sure you also have around a 1-2-inch gap between the stem and the start of the mulch ring.

If you are reapplying mulch, first rake the old mulch to even the layer and mix some into the soil if possible.  If your tree has already been mulched and has been volcano mulched, simply dig out the excess, exposing the root flare and creating that 1-2-inch gap between the stem and the mulch.

This simple act is relatively inexpensive, does not require a lot of time, and will help keep your tree healthy, extending its life.  If you notice any other issues with your trees, hiring an ISA Certified arborist is the next step in managing your trees’ health.  To find an arborist near you and verify credentials, use the link at Find an Arborist, Trees are Good, International Society of Arboriculture (ISA).

View the original article on the Purdue Landscape Report website: Simple Steps to Care for Your Tree: Mulching.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
Re-mulch Your Trees, Purdue Landscape Report
Find an Arborist video, Trees are Good-International Society of Arboriculture (ISA)
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Moist soil and rotten roots makes it easy for trees to come crashing down – Fox 59 News
Expert: Some storm damage can be easily prevented – Fox 59
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
Tree Pruning Essentials, Publication & Video, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment – The Education Store
Trees and Electric Lines – The Education Store
Tree Defect Identification, The Education Store
Planting Your Tree, video, Purdue Extension
Tree Installation, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Subscribe – Purdue Extension-FNR YouTube Channel

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

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