Plant Growth Management

By Patrick Anderson

Huge White Oak Tree by David Saddler
Huge White Oak Tree by David Saddler

Plant growth regulator.  That may sound scary to some, and counterintuitive to others.  Why would we want to intentionally stop a tree or shrub from growing, and how does that even work?  Believe it or not, it may actually benefit a plant’s health to slow its growth down. But, before we delve in to the specifics of plant growth regulators, or as I like to call them ‘plant growth managers (PGMs),’ it’s important to know that many of us come in contact with this technology quite often.

PGM History

PGMs first became popular in the floriculture industry to get uniform plants that would be merchantable when they made it to the garden centers.  Have you ever noticed your house plants start becoming leggy and a bit yellow after they’ve been in the house for a few weeks?  That is because the growth regulator applied before you bought them is wearing off.

Early versions of PGMs blocked cell division to accomplish reduced stem elongation (not unlike some herbicides).  Modern PGMs work within the plant to regulate the hormone (gibberellin) which is responsible for cell elongation.  This means the plant is still producing the same amount of cells, leaves, buds, etc. just extending 30%-70% less than normal.

Trees Need Pruning Less Often

This reduction in growth can lengthen time between pruning cycles for trees growing in close proximity to infrastructure, like that oak planted 10-feet from the corner of your house, those trees planted underneath the utility lines, or that hedge that needs to be trimmed a few times a year so you can see out of the front window.  Less pruning means less wounding for the tree (bonus for the tree), less work for you or a contractor (bonus for your wallet), and less ‘green-waste’ contractors have to dispose of (bonus for the environment).

Trees Handle Drought and Stress Better

Autumn Colors by Tiberiu Ana
Autumn Colors by Tiberiu Ana

PGMs also help a plant to mine more resources from the soil, and increases drought tolerance. While these growth managers are inhibiting the hormone responsible for tip elongation, they are encouraging the production of another plant hormone, abscisic acid, which increases fine root growth, reducing cell dehydration, and regulating leaf water loss.

PGMs can also increase the amount of chlorophyll the tree produces.  Chlorophyll is, of course, what gives a leaf its green color, and plays a major role in photosynthesis.  These effects of PGMs on plants are why many arborists are applying them to trees having just undergone, or which are about to undergo stress from construction activities.

Plant growth managers may seem a bit scary at first thought, but can be a great tree care tool when used correctly in our landscapes.  If you have more questions, ask your local Limbwalker, and they can guide you through the process of whether or not plant growth managers are right for your landscape.

If you have any questions about plant growth management, please call Limbwalker at 502-634-0400.

Compost Tea

By Royce Hall

Compost Tea Making at Granton Vineyards by Stefano Lubiana
Compost Tea Making at Granton Vineyards by Stefano Lubiana

The idea of using decomposing matter (compost) in gardens and managed soils is not a new one. People have been utilizing the benefits of compost for centuries. However, in the past few decades there has been a great deal of advancement and research on liquid compost products, known as compost teas.

What is Compost Tea?

It can be helpful to think of compost tea as a liquid suspension of beneficial microorganisms and minerals. Compost tea is created by taking good quality compost (usually from leafy and woody material) and vermicompost (worm castings), then “brewing” the tea with a mixture of natural food products, such as kelp, fish hydrolysate (ground up fish), humates (rich black completely decomposed organic matter), and molasses in several gallons of water. Tea brewers are designed to continuously aerate this liquid mixture for 12-48 hours. This process extracts the beneficial microbes (bacteria, fungus, nematodes, and protozoa) from the compost and encourages them to multiply, resulting in an extremely concentrated mix of microbes, as well as some minerals extracted from the compost. The idea behind compost tea is that you can gain the benefits of compost without the laborious work of spreading compost.


Limbwalker's BioTea®
Limbwalker’s BioTea®
  • Natural Nutrition – In nature, microbes break down organic matter, making the nutrients in the organic matter available to plants. By adding compost tea to your lawn or landscaped area, you can assist natural nutrient cycling. For maximum benefit, it is best also to add organic matter to your lawn or landscaped area for the microbes to eat. This can be done with compost, mulch, feed products (corn gluten meal) or fertilizers that have organic matter in them.

  • Micronutrients – Compost is very rich in micronutrients, like iron or manganese. Depending on the compost that goes into the tea, the mixture will contain many of these essential nutrients.

  • Diversify microbial life – While the soil is chocked full of microbes, sometimes a particular plot of land may be lacking in a particular variety of microbe which the compost tea can supply.

  • Disease control – A lot of research has been done on the preventive and curative effects of foliar compost tea applications (like this one). The basic idea is that the good microbes populate a plant’s leaf and prevent pathogens from settling down on the targeted plant. For best results, the compost tea must be applied frequently (every 7-10 days in some circumstances).


Compost tea contains billions of living organisms, and so one batch of tea will not be exactly the same as the next. At Limbwalker, we have our BioTea® professionally, independently analyzed yearly. These tests analyze the biological diversity and viability of our tea, as well as the nutrient value of our BioTea® ensuring that it is of the highest quality.

If you have any questions about compost tea or Limbwalker’s BioTea®, please call us at 502-634-0400, or contact Royce at

Avoiding Tree Care Scams

From the TCIA

TCIA letterhead

It can be tempting to hire the first tree care company you find. But doing your homework is imperative to saving money, ensuring quality, safe work, and avoiding tree care scams.

What is an Arborist?

Before even beginning your search, be aware that the credentials of someone calling themselves an arborist can vary widely. An arborist is a professional who cares for trees and other woody plants by pruning, fertilizing, monitoring for insects and diseases, consulting on tree related issues, and occasionally planting, transplanting and removing trees. Be wary of tree care scammers – don’t just hire someone with a chain saw who knocks on your door!

“With hundreds and possibly thousands of dollars at stake, not to mention the integrity and appearance of your property and your personal safety, make sure that you take your time in deciding which company you should hire,” warns Peter Gerstenberger, senior advisor for safety, standards & compliance for the Tree Care Industry Association (TCIA). “Disreputable companies are renowned for ripping gutters off, breaking fences and bird baths, and even dropping trees on houses. Then they typically fold up and leave, never to be seen again,” adds Gerstenberger.

A Few Things to Look ForaccreditationsTCIA

Homeowners searching for qualified tree care companies should look for the following:

  • Proof of Insurance: Ask for current certificates of liability and workers’ compensation insurance, if applicable. Be aware that if the tree care company you hire doesn’t have insurance or is not a legal company – you, the homeowner – could be held responsible as a contractor.

  • Good References: Ask for local references, and check on the quality of their work and level of service. Don’t be rushed by a bargain and don’t pay in advance.

  • Solid Reputation: Verify professional affiliations the company might have, such as memberships in business and/or professional organizations such as the Tree Care Industry Association.

  • Comparisons: Get a second opinion and quote. Always get the estimates in writing.

  • Up-to-Date Knowledge: Ask if they follow ANSI Standards. A professional arborist will be aware of the current safety, pruning, fertilizing, and cabling standards.

  • Contract: Insist on a signed contract as to cost, dates when work is to be performed, and exactly what is to be done.

There are also inherent dangers for one attempting tree care or tree removal – pruning large limbs, felling trees and especially climbing into trees are hazardous activities even for trained professionals. For safe and efficient post-storm work, hire a tree care professional with the experience, expertise and equipment to safely take down or prune damaged trees.

Use these tips to help avoid being the victim of tree care scam artists. To report a tree care scam, contact the Attorney General’s office in your state, the Better Business Bureau or the FBI.

Find a professional

A professional arborist can assess your landscape and work with you to determine the safest course of action. Contact the Tree Care Industry Association (TCIA), a public and professional resource on trees and arboriculture since 1938. It has more than 2,000 member companies who recognize stringent safety and performance standards and who are required to carry liability insurance. TCIA also has the nation’s only Accreditation program that helps consumers find tree care companies that have been inspected and accredited based on: adherence to industry standards for quality and safety; maintenance of trained, professional staff; and dedication to ethics and quality in business practices. An easy way to find a tree care service provider in your area is to use the Find Qualified Tree Care program. You can use this service by calling 1-800-733-2622 or by doing a ZIP code search at

Maryhurst Needs Your Help!

Maryhurst logo

Maryhurst is a behavioral health services organization which provides therapy and treatment for adolescent girls from across the Commonwealth of Kentucky who have been severely traumatized by abuse and neglect.  The main campus located in Louisville’s east end spans 14 acres.  Although a residential campus with cottages, school, wellness center and administrative buildings, the campus has a park-like setting and provides a “homey” environment for the girls in our care.

We have just learned that the trees on our campus are infected with the Emerald Ash Borer beetle.  Maryhurst is now struggling to cover the $10,000 cost which will rid the campus of the infestation.  As a non-profit organization, we must raise $2 million each year just to cover our programming needs and provide necessary services to the girls in our care.  It is difficult for us to make the Emerald Ash Borer beetle infestation a priority and find the funds to treat this issue. So, we are asking for your help in raising the $10,000 we need to protect our Ash trees.

If you or someone you know would like to assist Maryhurst by funding this project, please contact Jennifer Moran at 502-271-4520 or

The No-Till Philosophy

By Jeneen Wiche

Prepping the Garden
Prepping the Garden by Homeandgardners

One of the most anticipated rites of spring is dusting off the tiller and heading out to the vegetable garden for a little soil play.  It is one of those things you can’t plan for, though.  It becomes a waiting game because we can’t do it if the soil is too wet; we don’t want to do it if it is too cold and we only have the time to do it when the weekend rolls around.

Tillage Destroys Soil Structure

Well, what would you say if I told you that you were off the hook when it comes to spring tilling?  Tilling is passé; sure, it makes people happy to see a clean, freshly tilled garden, ready to receive seeds and seedlings in anticipation of a bountiful harvest.  The truth is too much tilling is bad for the soil.  Soil is not just dirt; it is a living organism and the more we disturb it the less alive it becomes.

Tilling the soil allows us to seed or plant the garden more easily; it also allows the developing roots to extend freely through the soil, but this is short-lived. Once rain visits the plot the pulverized soil becomes a smooth crust.  Soil scientist, Lois Braun explains, “Both air and water should easily infiltrate these pores for healthy root growth and for a healthy soil microbial life.  Tillage pulverizes larger clumps of soil (“aggregates”) into a fine powder which is easily washed by the next rain down into the soil’s pores, clogging them up.”  Put this way, it makes a great deal of sense.  We all know how important oxygen, moisture and drainage is for plant health so larger aggregate clumps of soil are ideal over finely tilled “powder” that more easily erodes or becomes compacted under foot or during spring rains.

Tillage, Decomposition, and Soil Organisms

Soil Comparison by USDA. Heavily tilled soil on left, non-tilled on right.
Soil Comparison by USDA. Heavily tilled soil on left, non-tilled on right.

The most important part of soil structure is organic matter.  Organic matter slowly decomposes (tilling speeds up the decomposition) and as it does it feeds our plants at a rate that matches the plants ability to uptake the nutrients.  Not to mention other living organisms that are in the soil that become displaced in tilled soil and may not be able to recover and function at their new depth.  From earthworms to beneficial nematodes, an intricate system of life lies beneath the soil’s surface.  And we forget about the white thread-like bodies of mycorrhizal fungi just beneath the soil surface that help to fix nitrogen in exchange for carbohydrates they collect from root nodes; in exchange they scavenge absorbable phosphate, making it available to our plants so we don’t have to…unless we are constantly tilling and disrupting the balance of life in the soil!

No-Till Weed Strategy

You should still use your spade, garden fork or cultivator to loosen the soil at planting, but forget tilling for weed control. Instead, try adding organic matter as mulch or newspaper covered in grass-clipping or compost to control weeds. For gardens that have good soil structure, try no-till this year and see what happens.

If you have any questions about soil structure, compost, or tilling, please call Limbwalker at 502-634-0400.

From the Editor

Limbwalker Retreat

Limbwalker Retreat 2014

By Royce Hall

Limbwalker’s Culture of Professionalism

One of our core values at Limbwalker is an attitude of professionalism. We accomplish this by hiring and recruiting excellent people, but also by encouraging further education among our employees. Here are a few of the accomplishments our staff has achieved:

-14 ISA Certified Arborists
-1 ISA Board Certified Master Arborist
-2 ISA Tree Risk Assessment Qualified Arborists
– 1 Kentucky Certified Professional Turf Managers
– 1 PLANET Landscape Industry Certified Technician

In addition to these individual achievements, Limbwalker is the first and only tree care company in Kentucky to achieve Tree Care Industry Association (TCIA) Accreditation. The TCIA audits Limbwalker yearly to make sure we are fully insured, and adhere to industry standards for our work quality, safety, ethics, and employee training while maintaining a high level of consumer satisfaction.

In This Edition

Frequently at Limbwalker we have clients express concern about the safety of trees around their property. The next question, of course, is what needs to be done to make these trees safe to be around. In her article, “Is Your Tree a Risk to You?” Jeneen Wiche gives us some guiding principles Certified Arborists use to assess the safety of a tree, and a few examples of how arborists can mitigate risk.

Another issue we deal with regularly at Limbwalker is insect damage to our clients’ valuable landscapes. In order to proper treat these landscapes, we must properly time our applications with the activity of the pest. Patrick Anderson in “Using Your Landscape to Predict Pest Pressure,” shows how we can monitor the environment around us to predict pest emergence. It can be as simple as seeing if there are flowers on your Dogwood tree!

Have you ever heard of Organic Matter? If you haven’t, I am sure you know of, and probably have used, compost (which is a source of Organic Matter). In his article, “Does Organic Matter (OM) Matter?” Royce Hall explains the benefits of Organic Matter and tells you about a few sources of Organic Matter on the market.

Is Your Tree a Risk to You?

By Jeneen Wiche

Leaning Tree
Leaning Tree by Chris_parfitt

Trees are wonderful assets in landscapes that add a lot of value to a property. But sometimes trees are perceived as threatening. People often worry about trees potentially damaging their property or themselves, even though the trees may pose very little actual risk. So, how do we determine if a tree is a risk to us?

The Arborist’s Certification Study Guide (published by the International Society of Arboriculture) contains a chapter on Tree Assessment and Risk Management which outlines the three main components to risk assessment. These factors include potential to fail, the environment that may contribute to failure, and the potential target (of that failure).

Potential Failure

Potential to fail encompasses many factors: the species, growth habit, branch structure (co-dominate, multi-stemmed or included bark), the apparent health of the root system, and any obvious defects like cracks, splits, wounds, or decay. Decay can be present but unseen. Arborists look for things like fruiting bodies (mushrooms), cracked or loose bark; and bees, carpenter ants or birds and other animals using cavities.

Poor pruning in the past can contribute, too. One significant cause of failure is the practice of topping trees. Topping should always be avoided. In fact, topping can greatly increase failure potential. A topped tree has difficulty compartmentalizing improper pruning wounds, increasing the chances of decay at the individual pruning sites. Topping also encourages weakly attached rapid new growth and it reduces the tree’s ability to photosynthesize and take in nutrients. Rapid, weak growth increases the potential of future partial canopy or complete canopy failure.

Environmental Factors

Environmental factors that may contribute to failure include things like heavy irrigation (where uprooting may be more likely), drought, soil compaction after construction, pollution and the history of the tree (wind, ice and mechanical damage to mention a few).

Potential Targets

Tall Vehicles Beware Leaning Tree Trunk by brownpau
Tall Vehicles Beware Leaning Tree Trunk by brownpau

Potential targets include things like structures, heavy traffic areas, driveways, roads, and people. When assessing a tree, the likelihood of damaging such targets should be taken into consideration. For example, a tree out in the middle of a field poses little threat to people and none to structures, so pruning is a viable option, or it may be the case that no action is necessary. However, a tree near a house which has lost half of its main branches, is multi-stemmed and has included bark may need to be removed.

A Certified Arborist can do restorative pruning to coax a damaged tree back into shape. Restorative pruning techniques can prolong the life of a tree that experiences significant damage. This restorative technique may require several years of selective pruning by a qualified arborist.

Another option to mitigate potential failure is to have a Certified Arborist install a cable or brace system into the canopy or trunk of your tree. If you install such a system, or currently have one in a tree, it is recommended that you have a Certified Arborist inspect the system annually.

If you have concerns about the safety of your trees, these guidelines can help you understand the risk involved in your situation. If you are concerned, it is best to contact a Certified Arborist for expert advice.

If you have any questions or concerns about trees around your property, please contact Limbwalker at 502-634-0400.

Using Your Landscape to Predict Pest Pressure

By Patrick Anderson

Forsythia blooms as crabgrass starts to germinate - pic by Joye`

Forsythia blooms predict crabgrass germination – pic by Joye`

Though it may seem hard to believe, the first flowers of spring will soon be upon us. It doesn’t take a horticultural aficionado to appreciate these brightly colored petaled reproductive organs of angiosperms. The yellows, whites, blues, reds, and purples are a welcomed site after a gray, cold winter. But, the emergence of certain plant species’ flowers can be the warning signs for the appearance of diabolical plant damaging pests.


The study of such environmental indicators is known as phenology. For those of you who want a more textbook definition, here it is: “phenology is the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation).” (Wikipedia)

Monitoring the life cycle of plants (leaf expansion, flowering, color change, etc.) has been used for centuries in agriculture to determine the appropriate timing of when certain crops should be sown.  In fact, the first record of phenology dates back to 974 BC (University of Wisconsin).

Growing Degree Days

Complementing phenology are growing degree days (GDD).   GDD are a measure of heat accumulation used to predict plant and arthropod development rates, such as when flowers of a particular species may bloom, or when a particular insect will become active. GDD are calculated by taking the average of the daily maximum and minimum temperatures compared to a base temperature (usually 50°F).

                                         GDD      =        (daily high + daily low)/2     –   50

Growing degree day charts highlighting common tree/shrub pests have been developed by the Ohio State University and Cornell University to name a few. Here is a helpful article and chart to help you use GDD in your landscape. You can monitor Kentucky’s GDD here (Be sure to the “base” temperature to 50).

Black Locust flowers predict EAB activity - pic (edited) by Paige Filler
Black Locust flowers predict EAB activity – pic (edited) by Paige Filler

The use of phenology and GDD is an important monitoring tool for integrated pest management practices in the landscape. The activity of many plant damaging pests coordinates to either the flowering or leaf expansion of common shrubs and trees, some of which may be in your backyard.

A Few Examples

For example, when the hanging white racemes of black locust flowers appear (500 GDD +/-), the invasive emerald ash borer adults are beginning to emerge.  The first flight of the adult dogwood borer corresponds to about 2 weeks after peak dogwood bloom (850 GDD +/-). Eight weeks after the full leaf expansion of red maple (1000 GDD +/-) the most vulnerable stage of gloomy scale appears.  These are just a few examples of using phenological indicators to predict the emergence of tree damaging arthropod pests.

Limbwalker keeps track of GDD each week as knowing when insect pests are active allows Limbwalker’s Certified Arborists to make precise treatments, which limits the amount of products applied in landscapes.  This also reduces the chances of harming beneficial, or benign, critters that make our plants their home. Being in tune phenology and growing degree days can be invaluable when developing a plant health care plan for our landscapes.

If you have any questions about insects or other lawn and landscape pests, please contact Limbwalker at 502-634-0400.

Does Organic Matter (OM) Matter?

By Royce Hall

Clay soil with little organic matter - by
Clay soil with little organic matter – by

I recently traveled up north with my family, and as we were passing field after bare field in of Illinois farmland, we were surprised by the dark rich color of their soil. It’s striking in contrast with the orangey clay we are used to in Kentucky. This dark material is known as organic matter, and it is something you should encourage in your lawn and landscape soils.

Loosens Soil

One main reason you should be interested in adding organic matter to your soil is because it helps loosen the heavy clay soils we have in Kentucky. OM particles are much larger than clay particles, making it is easier for air, water, and nutrients to penetrate the soil and become accessible to your plants.

More Nutrition

OM also holds nutrients very well. On a soil test you can see a soil’s ability to hold on to nutrients expressed as the Cation Exchange Capacity (CEC); the higher the number, the better the soil’s ability to hold on to nutrients. For example, predominantly sandy soils may have a CEC as low as 3, whereas clayey soils may be between 10 and 25. Soils rich in organic matter, however, may have a CEC between 50 and 100. The result is that nutrients are less likely to leach out of the soil and become pollution, and the nutrients stay available to the plants for longer. Carbon filters are engineered based on this same concept. Carbon particles have a lot of surface area, letting them cling on to a great amount of pollutants.

Not only does OM hold nutrients, but as it decomposes the nutrients naturally occurring in the OM become available to your plants.

Holds Water

OM can hold up to 90% of its weight in water. This means that a soil rich in organic matter has less storm water runoff since the rain penetrates deeper into the soil and be absorbed more readily. This also results in less erosion. After watering events, the additional store of water becomes available to plants, keeping them hydrated longer than they would be more in more sandy or clayey soils.

Sources of OM

Limbwalker adding compost to a lawn

There are many organic products on the market these days, but one of the best sources of organic matter continues to be quality aged compost. There are several local sources of compost, or you can create your own compost bin and compost your yard waste (you should not compost any material that has been treated chemically if you intend to use the compost on food products).

For lawn applications we recommend spreading the compost equally across your lawn at a depth of 1/4-1/2 inch. Any more compost and you may smother your turf.  Limbwalker provides this service using cutting edge technology and equipment after core aeration to incorporate the OM into the soil. We recommend this application for soils with less than 6% OM content. For garden applications, you can easily incorporate a few inches of compost with a tiller.

There are also many fertilizes you can buy that contain OM. Many people in the organic community use feed meals, such as corn gluten meal, for this purpose. There are also fertilizers that combine more traditional nutrient sources with organic materials. The result is a higher nutrient value fertilizer that also builds the soil (often at a lower price than purely organic fertilizers).

If you have any questions about Organic Matter or Limbwalker’s compost topdressing services, please call us at 502-634-0400, or contact Royce at

From the Editor: Fall 2014

Climber in Fall Color
Climber in Fall Color – Limbwalker Tree Service

By Royce Hall

2014 Kentucky Tree Climbing Championship

On October 18 come out to George Rogers Clark Park to cheer on your favorite Limbwalkers in the annual Kentucky Tree Climbing Championship. This free event is open to the public. There will be a supervised climb for the youngsters, and a number of local food truck options for lunch. So, come out and enjoy the show as Cory Petry, co-owner of Limbwalker, tries to defend his title and be crowned the Kentucky Tree Climbing Champion for the fourth year in a row.  For more information, click here.

Love Louisville Trees

If climbing trees is not quite your speed, maybe you should consider planting trees instead. Love Louisville Trees will have their next planting day on November 8 in the Shelby Park Neighborhood. If you would like to join the effort to reduce Louisville’s heat island by planting trees, please consider lending a hand at the next planting day. You can get more information through Love Louisville Trees’ facebook page, or contact Valerie Magnuson at . You may also be interested in this short article from WFPL news with Valerie Magnuson, the executive director of Louisville Grows, on the need for Louisville to continue planting more trees to replace the ones we are losing.

In this EditionLLT-vert-logo-1c-2

What do we mean when someone says a soil is unhealthy? Also, if our soil is unhealthy, how do we help it become healthier? In her article, “Healthy Soil, Healthy Plants,” Jeneen Wiche helps us define “healthy soil,” and speaks about how to preserve healthy soils through proper management.

Next, Patrick Anderson finishes his two part series on tree insects in his article, “Trees and the Bugs Who Love to Eat Them part 2.” In this article, Patrick helps us identify aphids, scales, and spider mites. Remember, the first step of controlling pest insects is to properly identify the insect.

Finally, Royce Hall gives some fall tips on how to manage the leaves falling on your lawn in his article, “What To Do With Leaves On Your Lawn?” Is it best to mulch the leaves or to bag them? Will mulching the leaves smother the grass or add to the thatch layer? Check out Royce’s article to find out.


Commercial Tree Services

Louisville’s award-winning Limbwalker Tree Service is ready to manage the trees on your commercial property. After an initial consultation with one of our certified arborists, we develop a plan to address the needs of your trees and to eliminate as much risk as possible to your property.

Click here to learn more