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It’s spring and soon the azaleas and rhododendrons will be blooming. I see azaleas referred to as rhododendrons and vice versa often. So I found a website that explains the similarities and differences. I have both deciduous and evergreen azaleas, but have been so unsuccessful with Rhododendrons. Both are beautiful. Check out this site for some information:

https://www.gardenia.net/guide/Azaleas-and-Rhododendrons-What-Difference

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Milan Lavender Farm

Naida writes:
I think many of our members do not know about Lavender Lane, a lavender
farm, located on Plank Road in Milan. They are having a Harvest
Festival Saturday, July 13. I will send their website for more
information. Milan Garden Club visited them last year, by special
invitation, and it is a very nice place. They also had a Harvest
Festival last year and I understand there was a real traffic jam by
their place with over 1,000 visitors so if anyone plans on going I would
get there early. Lots of good vendors. (I do not think they accept
visitors unless during the festival but folks could call and find out.)

https://www.lavenderlanemi.com/

Naida sent us in this information on OSU newsletter
The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer. Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article link below titles. To contact the authors, click on their names.
Be Alert for Boxwood Leafminer
https://bygl.osu.edu/node/1230
Authors Joe Boggs
Published on April 12, 2019

Boxwoods with yellow to brown leaves are common this spring throughout Ohio. Boxwoods with yellow to brown leaves are common this spring throughout Ohio. Some of the leaf discoloration is due to winter injury with foliage at the tips of branches or on the windward side of plants most heavily affected.

Some discoloration was caused by salt damage either directly with “ice melt” or rock salt inadvertently thrown onto foliage, or indirectly with “salt spray” carried onto foliage from nearby roadways. Salt damage is sometimes, but not always, concentrated on one side of the plant.

However, a close examination may also reveal the telltale blister-like leaf symptoms caused by the boxwood leafminer (Monarthropalpus flavus). Leafmines may be found throughout the plants although the highest concentration often occurs on foliage at branch tips.

Gently separating the upper and lower leaf surfaces (the leafminer had already done most of the work!) will reveal the bright yellow leafmining larvae (maggots) of this midge fly wiggling around in their blister mines. The larvae will complete their development in a few weeks and pupate. The pupae are also bright yellow at first, but turn orangish-yellow as this stage nears completion.

This non-native midge fly was accidentally introduced into North America from Europe in the early 1900s and is now common throughout Ohio. Adults emerge at around the same time red horsechestnuts (Aesculus × carnea) and doublefile viburnums (Viburnum plicatum) are in full bloom (440 GDD). Except for their bright orange abdomens, the adults superficially resemble miniature mosquitoes.

Females use their needle-like ovipositors to insert eggs between the upper and lower leaf surfaces of boxwood leaves. Each leaf may contain multiple oviposition sites with several eggs per site. These sites will become individual leafmines producing the blister-like leaf symptoms.

Eggs hatch in early-summer and the resulting larvae spend the remainder of the season consume interior leaf tissue as they develop through the 1st and 2nd instar stages. Winter is spent as 3rd instar larvae inside the leafmines. The larvae resume feeding in the spring and develop through a 4th instar stage.

Much of the leaf damage occurs in early spring with the ravenous larvae rapidly expanding their leafmines. Multiple leafmines in individual leaves may coalesce causing the upper and lower leaf surfaces to delaminate over the entire leaf. Individual mines may turn reddish-green at this time of the year with heavily mined leaves turning from yellow to orangish-brown causing the leafmining damage to be mistaken for winter injury.

A close examination of the leafmines at this time of the year may reveal small translucent “windowpanes” created by the larvae in the lower leaf surface. The pupae will wiggle through these weak points to ease the emergence of fragile adults.

This pupal activity is responsible for one of the most unusual features of this midge fly: reports of hissing, crackling, or rustling sounds coming from heavily infested boxwoods. I’ve reported on this strange phenomenon in past BYGLs. So, reports from gardeners or landscapers that they’ve heard boxwoods going snap, crackle, and pop should be taken seriously as the odd sounds are an indicator of a heavy boxwood leafminer infestation.

Damaging boxwood leafminer infestations can be suppressed through applications of neonicotinoids such as imidacloprid (e.g. Merit, Marathon, and generics) or dinotefuran (e.g. Safari or Zylam). However, applications should be delayed until AFTER boxwoods bloom to protect pollinators.

Boxwood blooms attract a wide range of pollinators; blooming plants can literally buzz with their activity. Delaying applications until blooms drop will result in some minor miner damage, particularly with the imidacloprid that is taken-up more slowly compared to dinotefuran. However, this is a small price to pay for protecting pollinators.

You may find recommendations for topical applications of pyrethroid insecticides such as bifenthrin (e.g. Talstar) to target adult leafminer females before they lay eggs. However, adults typically emerge in Greater Cincinnati while boxwoods are in full bloom, so I no longer recommend this application.

Plant selection provides a more long term solution to the depredations of boxwood leafminer by removing insecticides from the management equation. A helpful research-based listing of the relative susceptibility of boxwoods to the leafminer was published in 2014 by the American Boxwood Society in their “The Boxwood Bulletin” [see More Information below].

More Information
American Boxwood Society, Boxwood Leafminer Evaluation
http://www.boxwoodsociety.org/uploads/54_1_2014_Summer.pdf#page=9

How To Hire An Arborist
https://bygl.osu.edu/index.php/node/1229

Authors Amy Stone
Published on April 12, 2019
Ohio State University Extension’s Home Yard and Garden FactSheet HYG-1032 has been update and is available online. The OSU FactSheet includes tips for selecting an arborist and resources available to help find local arborists.

An arborist, by definition, is an individual trained in the art and science of planting, caring for, and maintaining individual trees. Arborists are knowledgeable about the needs of trees and are trained and equipped to provide proper tree care. Hiring an arborist is a decision that should not be taken lightly. Proper tree care is an investment that can lead to substantial returns. Well-cared-for trees are attractive and can add considerable value to your property. Poorly maintained trees can be a significant liability. Pruning or removing trees, especially large trees, can be dangerous work. Tree work should be done only by those trained and equipped to work safely in trees (ISA, 2018).

A huge thank you to Cindy Meyer with Warren County Soil and Water Conservation District for her work as a co-author and the photo used in this alert.
More Information
OSU Extension Home Yard and Garden 1032
https://ohioline.osu.edu/factsheet/hyg-1032

Green Tigers Prowling Forest Trails
https://bygl.osu.edu/index.php/node/1228
Authors Joe Boggs
Published on April 10, 2019

I spotted one of my favorite forest dwellers during a walk in the woods yesterday: six-spotted tiger beetles (Cicindela sexguttata). The beetles have a curious affinity for hanging out on woodland trails and they can certainly liven up a hike.

The beetles are well-named because these tiny “tigers” hunt, kill, and eat other insects. The overall color of these shiny beetles varies from deep emerald green to slightly bluish-green depending on the angle of the light. Six white spots are arranged along the trailing edge of the wing covers, three spots per side. The spots are small and sometimes obscured by light bouncing off their highly reflective shiny bodies.

The beetles have bulging black eyes (the better to see you with, my dear!) that makes them look like they’re wearing goggles. The beetles are agile flyers and their excellent eyesight coupled with long legs which gives them swift speed can make getting a close look difficult.

However, a close examination of this ferocious predator will reveal powerful sickle-shaped mandibles that are used to grab and dispatch luckless arthropod prey; a trait that is shared with other tiger beetles (family Carabidae (Ground Beetles); subfamily Cicindelinae (Tiger Beetles)). A word of caution: these carnivores can also use their impressive mandibles to deliver a painful bite to the hand of the overly curious.

Even the larvae of this tiny tiger are predators. However, instead of actively hunting their prey, they conceal themselves in vertical burrows in the soil to await hapless victims. When a meat item such as insects or spiders walks past, the tiger larva springs forth like a jack-in-the-box to grab dinner with their powerful mandibles.

The bottom line is that six-spotted tiger beetles are highly effective and important predators throughout their life cycle. So, keep your eyes peeled for and hands away from these tiny tigers prowling our woodland trails … and don’t kill them since they are good guys!

Magnificent Magnolias
https://bygl.osu.edu/node/1227
Authors Thomas deHaas
Published on April 9, 2019

Magnolias come in a range of flower colors and sizes.

The two most common in the landscape are Star Magnolia Magnolia stellata, which has a white flower, and Saucer Magnolia Magnolia soulangiana, which has a pale purple flower.

Many more cultivated varieties exist which include a yellow, Butterflies Magnolia Magnolia x. ‘Butterflies”, Magnolia x. loebneri ‘Leonard Messel’,

Magnolias can grow as a single stem tree form, which can reach 30 feet, or a small specimen tree that can be kept at 10 feet through pruning. Magnolias also come in a multi-stemmed small tree or shrub form.

The magnolias as a group are free from cultural problems except for an occasional outbreak of magnolia scale.

The one drawback as a group is because they flower so early; they can occasionally be burned by a frost, which will damage the flowers. But the solution is look to the ‘girl’ hybrids which bloom later:

By using varieties that bloom later, they tend be less susceptible to frost damage.
Take a look……………Magnolias are ‘MAGNIFICENT’

OHIO STATE UNIVERSITY EXTENSION
http://extension.osu.edu/

Where trade names are used, no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

Ohio State University Extension embraces human diversity and is committed to ensuring that all research and related educational programs are available to clientele on a nondiscriminatory basis without regard to race, color, religion, sex, age, national origin, sexual orientation, gender identity or expression, disability, or veteran status. This statement is in accordance with United States Civil Rights Laws and the USDA.

CFAES provides research and related educational programs to clientele on a nondiscriminatory basis. For more information: [ http://go.osu.edu/cfaesdiversity ].

Any materials in this newsletter may be reproduced for educational purposes providing the source is credited.

HOSTA COLLEGE

By Gail K.
As Master Gardeners-Advanced or Beginners: we are obligated to seek out educational
opportunities. This year, many of our membership attended the Growing Great Gardens
Seminar in Taylor, MI. Having attended this event (for the first time) last year; I opted to try
another seminar; just a 2 hr drive away-The Great Lakes Region-HOSTA COLLEGE in Piqua, Ohio.
From the onset, I noted some differences between the two.
Checking in at 7:30AM I could see a distinct difference in the age of the attendees. Many
appeared to be much more experienced in years than myself.

(registration, meet & greet and dining area)

Additionally, as I moved about the large meeting room which would serve as the dining area, I
could hear people calling out to each other as they renewed old relationships. Throughout the day
I would learn that attendees, vendors and speakers had come from Michigan, Ohio, Indiana, Kentucky
Pennsylvania and other states. A really wide variety of people & they all seemed to know each other.

A 2 day event-I only did the day with the classes.
Each class was an hour and I had 5 plus an hour of lunch. Felt
like I was right back in high school (ha ha) Although much of the focus was
on hostas-I had 64 topics I could choose from.

(just one table of hostas that were for sale in the vending area)

Many of the hosta classes filled quickly, as they allow membership to sign up first.
But despite having to wait to choose, I felt I had a wide array of topics to choose from.
I begin the day with a Hosta class, moved on to the Tall Bearded Iris, than I learned
to diversify my landscape (more so with trees & shrubs), then a lecture on
Trillium (this guy was from Michigan) and lastly 365 days of bloom-which had a focus
on Witch hazels. I loved the variety of classes and the #’s varied. Some classes were
full-30 people others only 10 or so. Made for very personal discussions.

Of course there were vendors– such as the one pictured above. Not as many, and not the variety
as the Growing Great Gardens. I did miss that aspect but I also spent less money on extras :).
There were booths from nurseries which brought along large stock plants such as trees and bushes.
DSC01212.JPG
Then there were the artsy ones—

There was a booth which had loads of books, another with
photos
There was the booth with papercrete products (had a class
on this)–much lighter weight than hypertuffa….

It lacked the group speaker programs but all in all, I felt it was a quality program. I will admit
I did miss seeing and mingling with fellow gardeners I know (love catching those Kodak moments)
and despite not winning one of the many door prizes they offered –

I did leave with my free hosta (Wiggles & Squiggles) and a wealth of knowledge on new topics. I am
happy with my decision to step out of my comfort zone and try something new. Now if only spring would get here!!!
GK

BYGL Weekly News

This was one of the sites Amy talked about Saturday. I subscribe and get a news-type letter every Monday. I thought this was an excellent and timely article. When you click on the red title you get more information and pictures.(Note from Linda: I had to add a link behind the title and you will find it bold but not red). I think our Blog folks would benefit from reading both these articles!The first article on tree girdling very excellent! I have had to cut several roots from my trees with this situation and on several trees it is just too late to do any cutting. This is something you don’t see happening with a thick layer of mulch so I recommend pulling that mulch away from the tree at least once a year to check what may be happening underneath it. Make sure you click on the red title for more pictures and information.
Thanks,
Naida

BYGL Weekly News for March 18, 2019

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer. Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article titles (The link is behind the title.) To contact the authors, click on their names.(link behind the name)

The Girdle you HATE to see! link: https://bygl.osu.edu/index.php/node/1215
Authors Thomas deHaas https://bygl.osu.edu/index.php/node/742
Published on March 14, 2019

In early spring, gardeners are looking to get outdoors and get something done. Why not check your trees and shrubs for girdling roots before the grass starts to grow or the mulch is applied. So what is a girding root? They are roots that cross over the flare at the base of a tree or shrub.

They come in all shapes and sizes. Some are small.
Some are big and numerous.

However, all can do harm to the tree. The remedy is to find them when they are small and cut or saw them away from the trunk of the tree.

What can cause girdling roots? Sometimes, in the course of nursery production, growers will miss removing the girdling root. A healthy tree should have a good basal flare without any crossing roots.

Sometimes girdling roots can be caused when trees are volcano mulched.

Joe Boggs has a good BYGL alert about volcano mulching at: https://bygl.osu.edu/node/1006 The take away is “If you see an unsightly girdle, get rid of it!” It might save your tree.

Dawn of Squirrelly Bark-Stripping! Link:https://bygl.osu.edu/node/1213
Authors Joe Boggs https://bygl.osu.edu/node/51
Published on March 13, 2019

Brian Heinz (Horticulturist, Spring Grove Cemetery and Arboretum) recently sent me pictures showing a dawn redwood (Metasequoia glyptostroboides) with the bark on the main stem stripped in patches. The damage extended from a few feet above the ground to around 20 – 25′ up the tree.

The bark-stripping damage was most likely caused by eastern gray squirrels (Sciurus carolinensis). Had the debarking occurred elsewhere in the U.S., the culprit could have been the North American porcupine (Erethizon dorsatum). However, it would be highly unlikely to find this fascinating prickly animal in southwest Ohio.

Squirrels can injure trees in two ways: by stripping bark and lopping off twig tips. The twig pruning most often occurs in the fall and causes no real damage. It may actually increase canopy density. However, destructive debarking by squirrels can potentially girdle trees. In fact, gray squirrels are considered a major non-native pest in the United Kingdom (UK) where they’ve changed their name to grey squirrels.

Eastern grays aren’t the only squirrels that strip bark. The peculiar behavior has been observed in North America with fox squirrels (S. niger) as well as two so-called pine squirrels; the red squirrel (Tamiasciurus hudsonicus) and Douglas pine squirrel (T. douglasii).

Gray squirrels are reported to strip bark on a wide range of deciduous trees. However, I’ve only observed damage to American beech, honeylocust, and maples in Greater Cincinnati. Although bark stripping has been reported elsewhere to occur throughout the growing season, most of the damage occurs in our region from March through early July.

I visited the dawn redwood tree on Monday and it was the first time I’ve ever observed bark stripping on this species. The pattern was slightly different compared to what I’ve seen on other tree victims perhaps owing to the dense, fibrous redwood bark. In fact, almost all of the bark on the main stem appeared to be roughened by the squirrels possibly owing to failed attempts to use their claws to prize the bark from the tree.

Thankfully, tree debarking by squirrels remains somewhat rare in North America. This is not the case in the UK. Eastern gray squirrels were introduced to various areas in the UK from the late 1880s through the 1920s. They are now wreaking havoc throughout the UK producing widespread severe debarking of woodland and landscape trees and threatening biodiversity; gray squirrels have caused regional extinctions of their native red squirrel (S. vulgaris).

A measure of the extent of the concern can be seen by visiting the “UK Squirrel Accord” website (see More Information below). The site notes, “The UK Squirrel Accord consists of 32 leading woodland, timber industry and conservation organisations [sic] in the UK. It was created at the invitation of HRH Prince Charles – who had the aim of bringing a concerted and coordinated approach to securing the future of our red squirrels and woodlands, and to controlling the introduced grey squirrel.” Pretty serious stuff.

Reasons posited on both sides of the Atlantic for the odd bark-stripping behavior has ranged from reasonable hypotheses such as feeding on the sugar-rich phloem, searching for a water source, gnawing on trees to wear down ever-growing incisors, to the bizarre such as pregnant female squirrels gnawing bark in response to their pain.

A Calcium Deficiency?

Another possible explanation was provided in a paper titled, “A novel causal mechanism for grey squirrel bark stripping: The Calcium Hypothesis,” that was published by a group of UK scientists in February 2016 (see “More Information” below to access the entire paper).

The authors did a literature review and then synthesized their findings to develop the hypothesis. Citing past research, they noted it is well documented that gray squirrels will gnaw on calcium-rich sources such as bones, antlers, and even limestone.

They also found that debarking is most common after a good mast year supports an elevated population of juvenile squirrels in need of calcium to build bone as well as post-pregnant females in need of replacing lost calcium during pregnancy and nursing.

Finally, they linked the need for calcium by squirrels to the elevated levels of available calcium in tree phloem in the spring to early summer. The authors state, “Calcium can increase in the phloem by as much as 40% in trees in Spring and Summer after Winter dormancy, as it is required for growth.”

The Plot Thickens

Of course, science remains in constant motion. In June 2017, the same authors published, “Regulation of bone mineral density in the grey squirrel, Sciurus carolinensis: Bioavailability of calcium oxalate, and implications for bark stripping” (see “More Information” below to access the entire paper). Their second paper seems to refute their earlier Calcium Hypothesis which is science at its best!

Although the authors noted their second paper was based on a relatively small-scale study (18 grey squirrels), they investigated the ability of squirrels to use calcium oxalate (CaC2O4) to build bone. Calcium oxalate, which is also abbreviated as CaOx, is the dominant form of calcium in tree phloem. However, the authors note that many animals cannot utilize this form of Ca for building bone

The long and short of it is the researchers found no differences in femur length between squirrels fed three diets: a diet with CaOx; a diet with low-Ca; and a control group fed a diet with calcium carbonate (CaCO3) which is a form of Ca known to be readily utilized by animals to build bone. More telling, the total Bone Mineral Density (BMD), which is a measure of Ca incorporated into the bone, was higher in the squirrels fed the control diet compared to those fed the CaOx diet, but there was no difference in BMD between those fed the CaOx diet and those on the low-Ca diet.

Based on their results, it would seem that squirrels may not be stripping bark to acquire Ca since they are not able to use the form of Ca in the phloem to build bone. Of course, the authors also recognized the shortcomings of their research methodology. Along with the small sample size, they only assessed 10 males and 8 females. They also only had one sub-adult. An important part of the Calcium Hypothesis is that the bark-stripping behavior is associated with juvenile squirrels in need of Ca for bone growth or females trying to acquire Ca for enriching milk fed to their offspring.

The reason for their small sample size highlighted challenges they encountered with conducting thorough research studies on squirrels not the least of which is money and societal concerns. Here is their explanation: “This was an arbitrary sample size chosen for this small-scale study to garner an understanding of the effect of the three custom-made treatment diets, and because it is divisible by three. This number was also restricted by the cost of the treatment diets, and an ethical obligation to keep the total number of individuals involved to no more than scientifically necessary.”

A Call to Arms

I’ve provided a very short overview of these papers. However, the authors were clear that more research must be done to truly pin down the reason(s) for the odd bark-stripping behavior by grey squirrels in the UK (and gray squirrels in the U.S.). Sometimes we become frustrated with hearing, “more research is needed;” however, more times than not, that is the truth of the matter. It gets us closer to the bone.

More Information
UK Squirrel Accord
http://squirrelaccord.uk/
2016: “A novel causal mechanism for grey squirrel bark stripping: The Calcium …
http://www.sciencedirect.com/science/article/pii/S0378112716300421
2017: “Regulation of bone mineral density in the grey squirrel, Sciurus caroli…
http://onlinelibrary.wiley.com/doi/10.1111/jpn.12740/full

OHIO STATE UNIVERSITY EXTENSION http://extension.osu.edu/

Where trade names are used, no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

Ohio State University Extension embraces human diversity and is committed to ensuring that all research and related educational programs are available to clientele on a nondiscriminatory basis without regard to race, color, religion, sex, age, national origin, sexual orientation, gender identity or expression, disability, or veteran status. This statement is in accordance with United States Civil Rights Laws and the USDA.

CFAES provides research and related educational programs to clientele on a nondiscriminatory basis. For more information: [ http://go.osu.edu/cfaesdiversity ].

Any materials in this newsletter may be reproduced for educational purposes providing the source is credited.

Here’s a link that Michigan Master Gardeners Association posted on Facebook. It’s a new online course. Check it out
https://www.canr.msu.edu/news/become-a-champion-for-pollinators-with-new-online-course-from-msu?fbclid=IwAR2kWYqhJBz0AUpPCVTTXatPgn71qmiD8Gkxqh4UKHWLIuewsvZWp5vfYMA

Pollinators

Stella sent over a site to check out on pollinators:
https://www.pollinator.com/

You may also want to check out this site that Jennie sent me:
https://www.pollinator.org/