An Introduction to NCSU Plant Disease and Insect Clinic

by Andrea Laine, EMGV

You know you’re a serious gardener when you get excited about preparing a sample for the NCSU Plant Disease and Insect Clinic. I just wish I had engaged this problem-solving staff sooner and I hope you will learn from my experience.

Over the last three or four years, the mature evergreen azaleas in my landscape – of which there were many – began to succumb to a sudden dieback. Where there was once dark green glossy leaves and abundant flowering, seemingly overnight a swath of vertical branches would turn brown and die. I was alarmed, but knew not what to do. So, I did next to nothing: I trimmed out the crispy parts and hoped for the best.

I am ashamed to admit this experience was after my master gardener training. In training we certainly learned about the services provided by the Plant Disease and Insect Clinic, but either I didn’t think my plant problem was important enough to bother someone at NC State, or I was too lazy to prepare a sample. Probably a little of both.

Inspired to act

Fast forward to this summer when two things happened that inspired me to act. First, the mysterious dieback attacked a stand of azaleas that are a key structural element in the design of my landscape (see photos above). And secondly, I noticed the exact symptoms on a few azaleas in a Durham neighborhood far from my own. The problem no longer belonged just to me; I resolved to seek a diagnosis on behalf of all of us.

My first step was to collect a soil sample from the vicinity of the azalea with the most recent dieback. The results showed that the soil pH was too high – 6.2 – where azaleas prefer a number between 4.7 and 5.3. Phosphorus was high and potassium was a little low. While all that is not a great situation for these acid-loving plants, it did not explain the sudden dieback. I needed to delve deeper.

I decided to access the NCSU Plant Disease and Insect Clinic. (You’ll find a direct link to it on the right side of this blog’s homepage as well as in the list of resources below.) I dug up a smaller azalea that had browned out a year or so earlier, left a good bit of the roots and soil intact and plunked it into a double plastic bag. Back indoors, I downloaded a submission form from the Clinic’s website, filled it out to the best of my ability and brought it and the sample to the master gardener office where I enlisted the help of our County Ag Agent Dr. Ashley Troth. Ashley submitted the sample on my behalf and we included digital images of the affected plants in my landscape. The more information a client can provide, the better will be the diagnosis and recommendations.

I had decided to remove these small, scraggly azaleas from the landscape anyway. So, I used half of one as my sample to the Plant Disease and Insect Clinic. Photo by A. Laine.

A diagnosis

A week later the diagnosis was in:  Symptoms are typical of Phomopsis dieback, a fungus disease. “The disease can be very serious if the fungus moves into larger branches and the base of the plant. This dieback was found down into the base of the plant submitted,” wrote Shawn Butler, an ornamentals diagnostician. “Presence of this disease,” he continued,  “often is an indicator of stressed or injured plants. Photos show that there is probably a problem in the root zones of these plants.  No root rot pathogens were isolated from these roots.  If the plants have been water-stressed in the past, then that might be the primary problem.” 

He also sent a root sample out to check for presence of damaging nematode populations. Some parasitic nematodes were found but populations were not high enough to cause damage.

A new pledge

I will take away at least two lessons from this experience (and I hope you do, too). The first is to seek help sooner, and the second is to not ignore long-established shrubbery. (These azaleas were planted at least 20 years ago.) The plants I inherited with my landscape deserve tender-loving-care equal to that which I provide to the plants I personally select for the landscape. 

Yet another azalea is affected. Removing it would leave a hole in the bush to the right as they have grown together over the decades. Photo by A. Laine.

Resources & Further Reading

How to submit a sample to the clinic: https://projects.ncsu.edu/cals/plantpath/extension/clinic/submit-sample.html

Meet the staff
https://projects.ncsu.edu/cals/plantpath/extension/clinic/about.html

Fees for the Clinic’s diagnostic services: https://projects.ncsu.edu/cals/plantpath/extension/clinic/services.html

Azalea care – a factsheet from Clemson University
https://hgic.clemson.edu/factsheet/azalea-care/

A comment about old azaleas from Louisiana State University
https://www.lsuagcenter.com/portals/blogs/southerngarden/problems-with-old-azaleas

Our Straw Bale Gardening Experiment

by Marty Fisher, EMGV

After three painful years of crop-destroying diseases on our beloved heirloom tomatoes, my husband and I decided to give straw bale gardening a try.

I had tried grafting—attaching an heirloom scion onto a hardy root stock—for two years with some success, but it was a long, painstaking process, and we still weren’t getting the yields we enjoyed in the days before the dreaded fungal, viral, and bacterial diseases took over in our garden. We also tried disease-resistant tomatoes like Early Girl, Better Boy, Celebrity, Sweet 100, etc., but we missed the complexity of flavors and variety of colors of our favorite heirlooms like Carbon, Amana Orange, Green Zebra, Pineapple, Lucky Tiger, and more. We also tried removing the lower branches of our plants to keep them away from disease spores in the soil as well as spraying with copper sulfate—it all seemed a lot of work for a limited return on investment!

I started researching straw bale gardening in January, thinking it offered the advantage of a sterile environment for the tomato plants as well as the effect of a raised be d. I found a book written by the man who pioneered the concept, Joel Karsten. He came up with the idea after observing healthy, vigorous weeds sprouting in old straw bales on his family farm. He began experimenting with vegetables, and over decades, developed the techniques for gardening with straw bales. Since then, he has published two editions of his book, Straw Bale Gardens, and has spoken all over the world about what is touted on the book jacket as “the hottest new method of veggie growing.” The book contains a wealth of useful information, plans, diagrams, and more.

Our first task was to find straw bales—they must be wheat straw bales, not hay. They are not cheap, especially given the size of our garden. The best price we found was about $6 a bale. We inquired about delivery and were told by several farm supply stores that they sell the bales at a loss or break-even and were not interested in delivering them. So, several pick-up truck trips later, we had lots of bales on our garden site. 

The next step was placing and conditioning the bales, a process that takes 10-12 days. Conditioning should be started two weeks before the average last frost date. 

Although I had reservations about the fertilizer recipe given in the book, we decided to just follow the instructions and evaluate the results. Over the conditioning period, fertilizer and water are applied to the bales according to a day-by-day schedule. My reservation concerned the recommendation of nitrogen-rich “traditional refined lawn fertilizer.” Instructions are also given for organic nitrogen sources, but this seemed more complex, and we followed the conventional method. Fertilizer is sprinkled over the top of each bale, and water carries it deep into the bale, starting the bacterial process of breaking down the bales to release nitrogen.

On Day 10, the instructions call for one cup per bale of 10-10-10 general garden fertilizer, watered in. 

Planting can begin on Day 12. A little sterile potting soil can be used to anchor the plant in the straw bale, but all the nutrients and growing medium the plants will need are contained within the conditioned bales. Adding garden soil or compost could introduce fungal spores to the sterile bales.

Results  

Our concerns about using lawn fertilizer were confirmed over the spring and early summer: TOO MUCH NITROGEN! Our plants quickly became enormous, with fewer blooms than normal. They also began to shade out the eggplants and herbs that we had planted beside the tomato plants. We added a phosphorous- and potassium-rich fertilizer and gradually the plants started to have more blossoms and bear fruit. We also noticed that plants growing in straw bales require more diligent watering. Karsten recommends placing soaker hoses on top of the bales, controlled by a timer. 

In researching this article, I found an N.C. Cooperative Extension Service article (see “Hay” Bale Gardening link below) that recommends a different conditioning method. It calls for simply watering the bales for three days. On Day 4, you add 2 cups of dolomitic limestone and a half cup of ammonium sulfate, and water it in. On Days 5-9, you add more ammonium sulfate, followed by a cup of 10-10-10 or 8-8-8 on Day 10. Planting commences on Day 11.

This year we did lose a few plants to “the *%#* fungus,” our common term for fungal, viral, and bacterial diseases including early blight, late blight, fusarium wilt, tomato spotted wilt, various cankers—you name it. My husband also sprayed the plants with copper sulfate as a preventative. 

Overall, we deemed the straw bale gardening experiment a success. We canned, made salsa, roasted, sliced, and froze plenty of colorful tomatoes to get us through the winter. We plan to try it again next year using the Extension Service-recommended fertilizer recipe.

I also plan to graft tomatoes again next year after taking this year off. And, I’ll give some of the newer disease-resistant varieties a try. Some I’m particularly interested in include Iron Lady, described as “super resistant,” and Mountain Magic, which was developed by Dr. Randy Gardiner, professor emeritus at North Carolina State University. Apparently, some breeders are also developing disease-resistant heirlooms, including two old favorites of mine, Lemon Drop and Mr. Stripey.

This was our first harvest this year–it got better after we adjusted the fertilizer.
Good old fashioned canned tomatoes! Heirlooms make the jars so colorful.
Tomatoes growing in straw bales in our garden. In addition to diseases, we also battle squirrels, hence the large cage under construction.

All photos taken by Marty Fisher.

Sources

Straw Bale Gardens Complete, by Joel Karsten

Understanding Tomato Varieties:
https://lee.ces.ncsu.edu/2019/05/understanding-tomato-varieties/

How to Grow Better Tomatoes
https://forsyth.ces.ncsu.edu/2018/05/how-to-grow-better-tomatoes/

Grafting for Disease Resistance
https://content.ces.ncsu.edu/grafting-for-disease-resistance-in-heirloom-tomatoes

Blight Resistant Tomato Varieties Worth Growing
https://www.growveg.com/guides/blight-resistant-tomato-varieties-worth-growing/

“Hay” Bale Gardening
https://pamlico.ces.ncsu.edu/2013/05/hay-bale-gardening/

Getting Back to Basics

September is synonymous with school. So, this week we are getting back to basics with a post that defines foundational gardening terms. The better you understand these terms and phrases, the easier it will be to identify, select and care for plants in your landscape.

Growing season:  The period between the beginning of growth in the spring and the cessation of growth in the fall.

Hardiness zone:  Expressed as a number and letter combination from 1a to 13b, the US Department of Agriculture has assigned a zone to every geographic area of the United States based on the average annual minimum winter temperature. Tags on plants sold commercially often identify the zone(s) in which the plant will grow.   

Microclimate. Climate affected by landscape, structures, or other unique factors in a particular immediate area.

N-P-K:  Acronym for the three major plant nutrients contained in manure, compost, and fertilizers. N stands for nitrogen, P for phosphorus, and K for potassium.

Coreopsis major, blooming along roadsides now, is a native perennial hardy in zones 5a to 9b. It attracts butterflies and songbirds and is deer resistant. The flowers are large (for coreopsis) and the stems are tall. Photo by A. Laine

Annual: Plants started from seed that grow, mature, flower, produce seed, and die in the same growing season.

Biennial: Plants that take two years, or a part of two years, to complete their life cycle. By freely reseeding, a biennial plant may seem to come back year after year, but you are actually seeing new plants.

Perennial: A plant that lives more than two years and produces new foliage, flowers, and seeds each growing season. Tender perennial:  A perennial that is not tolerant of frost and cold temperatures. Applying a winter mulch can help it survive It may die off above ground and regrow from the roots.

Woody perennial: A plant that goes dormant in winter and begins growth in spring from above-ground stems. Herbaceous perennial: A plant that dies back in the winter and regrows from the crown in spring.

Exotic: A plant of foreign origin or character; not native; introduced from abroad, but not fully naturalized.  Naturalize: The process whereby plants spread and fill in naturally.

Native plant: A plant indigenous to a specific habitat or area. Nativar: A plant that is a cultivar of a native plant. Cultivar: A cultivated variety of a species. Propagation of cultivars results in little or no genetic change in the offspring, which preserves desirable characteristics.

Integrated pest management. A method of managing pests that combines cultural, biological, mechanical, and chemical controls, while taking into account the impact of control methods on the environment.

Invasive. Growing vigorously and outcompeting other plants in the same area; difficult to control.

Noxious weed. Weeds that have been declared by law to be a species having the potential to cause injury to public health, crops, livestock, land, or other property. Noxious weeds are very invasive. There are 124 plants in NC that meet the legal criteria.

When a gardening term has you stumped, refer to the glossary chapter of the Master Gardeners Handbook for a definition – there are hundreds of entries — and a small dose of continuing education.

— A. Laine

Resources & Further Reading

Glossary Chapter of Master Gardener Handbook: https://content.ces.ncsu.edu/extension-gardener-handbook/glossary

Find your plant hardiness zone:  https://planthardiness.ars.usda.gov/
USDA Plant Hardiness Zone Map, 2012. Agricultural Research Service, U.S. Department of Agriculture.

Noxious weeds in NC: https://plants.usda.gov/java/noxious?rptType=State&statefips=37

https://plants.ces.ncsu.edu/plants/coreopsis-major/

September: To Do in the Garden

by Gary Crispell, EMG

Well, here it is … September! Some of y’all have been waiting for this since last October. For many, it is the beginning of your favorite time of the year—warm days, cool nights, lower humidity, winding down the summer garden … hurricanes. Enough contemplation! There is still much gardening to do this month. Let’s get to it.

Fertilizing
With the exceptions noted under “Lawn Care,” you can take your fertilizer and stick it in an air tight container and put it away until Spring.

Pruning
NOPE!  Fuggeddaboutit. If you must exercise your pruning tools go remove underbrush or unwanted saplings or something. Stay away from your landscape plants.

Spraying
Stuff to look for and where to look for it:  Wooly adelgid on Hemlock, spider mites on other coniferous evergreens, lace bugs on Azalea and Pyracantha and tea scale on Euonymus and Camellia.

A note about Lace Bugs. They will be active all year anytime the leaf surfaces are warm enough (e.g. about 40 degrees). Being diligent now will help keep them at bay after you have cleaned and put away your sprayer. Also, Azaleas planted in sunny places will have more lace bug issues than those planted in shade.

Spray Peach trees and Nectarine trees for Peach Tree Borers.

Maintain your rose program.

Be watchful in your Fall garden. Many insects and diseases are more active in the Autumn; They like this weather, too.

Weeds to be controlled this month:  Trumpet Creeper, Bermuda Grass and Blackberry.

Only spray if necessary.  Spray as little as possible. ALWAYS READ THE LABLE!

Lawn Care
September is the best time to seed and/or reseed a Tall Fescue lawn. Loosen the soil in bare areas and cover any areas larger than one square foot with wheat straw.

Apply lime and fertilizer as recommended on your FREE SOIL TEST.

Do not fertilize warm season grasses (e.g. Bermuda, Centipede, Zoysia). Fertilizing them now is like giving sugar to your kids at bedtime. They get real active much to their (and your) detriment.

If you missed the August window to treat your lawn for grubs, it is still open until the middle of September.  After that the little buggers quit feeding and go to sleep for the winter.

Propagation
You may dig and divide spring flowering bulbs now. Daffodils will be especially appreciative of this activity and will show it in the Spring.

Other Stuff to Keep You Outdoors on Gorgeous Autumn Days
Mulch shrub and flower beds.

Clean up and put away sprayers and other gardening equipment that won’t be used again until Spring.

Get your houseplants ready to come back inside. Break it to them gently by bringing them in for a little while each day. Be sure to rid them of insect pests before they come in for good.

If you do not have a fall garden, (What do you mean you don’t have a fall garden?!?) then it is time to chop, burn or toss dead vegetable plants. Burn or toss, especially if they had disease or insect issues.

Checkout the local garden center for spring flowering bulbs you can’t live without (or just covet a whole lot).  October and November will be the time to plant them. You know, “Shop early for the best selection.”

Find a good trail and take a hike. Take your kids or grandkids to the park. Read a book on the deck or patio. Get out of the house with any excuse you can come up with.

See ya’ in October for leaf season.

An Upcycle Garden Idea: Build a Living Wall

By Wendy Diaz, EMGV

The first time I remember seeing a living wall (or vertical garden) was along ‘Museum Mile’ in Madrid, Spain on April 2010 (see photo 1). The green wall was designed by Patrick Blanc, a French botanist famous for creating vertical gardens in Europe1. I was intrigued and took several photographs because I just couldn’t believe the scale of this immense beautiful patterned wall covered in very healthy and vibrant plants. It did not seem possible that so many plants could be so healthy on a very narrow vertical surface and it did not even cross my mind at the time to attempt a vertical garden at home. 

Photo 1 Living Wall designed by Patrick Blanc along Museum Mile in Madrid, Spain. Photo by Wendy Diaz April, 2010

Then, I attended a Durham Garden Forum Talk at Duke Gardens on February 20, 2018 by Leslie Herndon of Greenscapes, Inc.2 and she inspired me to think about attempting a scaled down version of vertical gardening using, among other things, nothing simpler than a wooden pallet. All any home gardener needed was a little inspiration, and in my case, my husband to help me lift and assemble the required materials. I decided it was something I wanted to try doing and I had just the spot. The idea for the location presented itself last fall when I cut down the wisteria in my backyard (see photo 2), on the east side and backyard of our property, as part of my ongoing plan to remove all invasive species from my yard. It left a bare hole (see photo 3 and 4) between two remaining support posts of an old children’s fort my husband built many years ago.  We decided to hang the pallet from the cross board between the posts to provide a screen in the backyard until my newly planted cross vine spread. 

Photo 2 Chinese wisteria (Wisteria sinensis) before removal in my back yard. Photo taken November 5, 2018 by Wendy Diaz
Photo 3 Chinese wisteria (Wisteria sinensis) stems after cut-back. Photo taken November 11, 2018 by Wendy Diaz
Photo 4 Hole in landscape between two support posts after Chinese wisteria removed. Two birds enjoy the new space created. Photograph taken November 12, 2018 by Wendy Diaz

Materials 
Oak pallet
Staple gun and staples
Three coffee bean bags burlap, no holes
Potting soil (about 1 cubic feet)
Scissors or knife to cut burlap

Plants
Sedum (spreading variety)
Coleus (Plectranthus scutellarioides)
Basil
Spider plants (Chlorophytum comosum)
Caladium

I didn’t want to spend a lot of money so I split some of my houseplants, propagated some basil, used some extra caladium bulbs I saved from last year’s frost and uprooted some ground-cover sedum from my yard. I did purchase the coleus and salvia. I already had a small wood pallet left over from a recent bathroom renovation.

I went to the Scrap Exchange and purchased used coffee bags for $2 each and borrowed my husband’s staple gun. I cut the coffee bags along their seams for a single layer and cut out a space in the bag for the center post of the pallet and wrapped the bags around each wooden plat to make a pouch for the potting soil and stapled it to the boards (see photo 5 and 6).

Photo 5 Bottom right hand corner of Hanging Garden with burlap wrapping to make plant pouches. The rabbit is curious. Photo taken April 13, 2019 by Wendy Diaz
Photo 6 Side view of burlap coffee bag wrappings. Hanging Garden also provides a perch for birds. Photograph taken May 6, 2019 by Wendy Diaz

Initially, we used two stainless steel screw eyes to hang the pallet but it almost touched the ground (see photo 7) so my husband raised it to the first notch on the side panels and screwed it to the cross beam between the support posts (see photo 8). My husband had to secure the posts with concrete due to the weight of the oak wood pallet and wet soil. It took just over a month to for the plants to fill in (see photo 9).

Photo 7 Initially the Hanging Garden was suspended by two screw eyes but it was too close to the ground and my sedum would not be able to trail over the edge of the bottom pouch. Photograph taken on April 13, 2019 by Wendy Diaz

Photo 8 Hanging Garden secured to cross beam between two support posts about 1 foot above the ground surface. Plants were placed in three layers on April 13, 2019. Photo taken April 24, 2019 by Wendy Diaz
Photo 9 Plants are thriving in Hanging Garden and most of the pallet is covered with plants. Photo taken July 25, 2019 by Wendy Diaz

Leslie Herndon recommended an Internet search on the words “DIY Living Wall” to get some ideas and see other projects. She also recommended fabric stapled to the back of the pallet to protect the wall but because we were suspending it from old support posts, I decided to try to achieve the reversible affect and hope the plants would grow in front and back (see photo 10). After a few months, plants grew out of the back, though not as fully due to shade and the burlap covering. I now call my living wall the Hanging Garden and it achieved my purpose of providing a screen and filling in the hole left by the wisteria vine. In the end, my Hanging Garden became the most thriving part of my backyard during our heat wave in July and a focal point looking out our picture window. I am well pleased with our efforts.  

Photo 10 View of shaded back of Hanging Garden in the morning. Photo taken July 30, 2019 by Wendy Diaz

In Hindsight
One of things that I will do differently next time is to install an automatic watering system because we had to hand water the shallow soil pockets twice a day to prevent wilting in July. We would also put more concrete in the hole of the north support post because it is now leaning with all the weight of the established plants. Next time, I will not plant salvia (not enough sun at this location) and I would place basil in the top pouch of the pallet and try some coral bells. Maybe next spring I will arrange plants to make a geometric design with common plant textures and more colors and even add a nonliving accessory as recommended by Ms. Herndon2.

I am not a professional and my first attempt wasn’t a work of art nor to the scale of a Patrick Blanc creation, but it surpassed my expectations so I am going to replant it next year!

Photo 11 Photograph taken July 30, 2019 by Wendy Diaz

References:

  1. https://www.npr.org/sections/parallels/2017/07/09/495905421/hot-dry-madrid-aims-for-a-cooler-greener-future
  2. https://www.greenscapeinc.com/gallery/commercial-property-gallery/retail

More reading:

  1. http://www.greenroofs.com/projects/
  2. http://www.greenscapeinc.com/blog/how-much-do-living-walls-cost
  3. http://www.verticalgardenpatrickblanc.com