Pests and Diseases: Blossom End Rot

blossom end rot
Photo courtesy of www.mofga.org

Blossom End Rot. Just the mention of it elicits all kinds of negative responses from vegetable gardeners. Those negative responses can involve frustration, anger and even curse words. For those of us veggie gardeners that start our tomatoes from seed, here is a typical progression of the season: You plant the seed in a nice warm, well lit area in your home so that it can get a good head start. You nurture that plant until it’s warm enough to be planted outside. You harden it off before planting. You amend the soil and finally it’s time to plant. You take great care planting it and water it in well so that it isn’t stressed in its first few days in the garden. You water the plant until it’s time to stake it. You stake it so the fruits wouldn’t be damaged from touching the ground. You continue to water it and then that magic moment happens. The green fruits ripen to a beautiful red and you go to pick your first tomato of the season. THIS is what you’ve waited for all season. All of your hard work culminates with…a tomato that has a big rotten spot on the end. Ughhhh!

blossom end rotBlossom end rot, otherwise known as BER, occurs on the “blossom end” of your fruit…the end opposite the stem. And lest that you think it only occurs on tomatoes, it can also happen on peppers. There are two main things that pre-dispose your tomatoes and peppers to BER. The first is a calcium deficiency in the soil. Calcium is needed for cell growth and if there isn’t enough calcium in the soil to “feed” the expanding fruit, the cell walls collapse and you end up with a mushy mess. The other major concern is soil moisture. That is directly related to the calcium issue. Nice and even soil moisture makes for nice and even tomatoes (does that description even make sense?) But alas, life is not perfect and we end up forgetting to water or God doesn’t provide enough rainfall to meet our tomatoes’ needs. Or we end up with a deluge of water like the central Virginia area did this past weekend. We received 5″ of rain! Five i-n-c-h-e-s of rain. I am beyond thankful for the rain after our many days of 100 degree weather and 0″ of rain. But…it won’t be good for the tomatoes.

So what can you do to prevent blossom end rot? There are several ways that you can reduce your chances of squishy, yucky ended tomatoes and peppers:

  1. Amend your soil so that it contains more organic matter. Organic matter helps to regulate soil moisture and that will help to prevent BER.
  2. At planting time, add a handful or two of Epsom salts to the planting hole. Epsom salts contains a readily available form of calcium that the plant can uptake. We did this last year (we forgot this year) and we had a great tomato season. This year…the tomatoes have blossom end rot.
  3. Mulch. Mulch, mulch, mulch. Again, it helps to regulate soil moisture. With even moisture comes those nice and even tomatoes we talked about earlier.
  4. Water evenly. I know that this is easier said than done but it really does help. While you can’t prevent 5″ of rain from reaching your plants (but then again, why would you want to?), you can help even out the dry times. Water deeply 2-3 times per week instead of lightly everyday. By watering deeply, you encourage your plants’ roots to dig deeper in the soil in search of H2O.

 

There’s one other thing that I wanted to mention about blossom end rot: if your fruits are infected, it doesn’t mean that you can’t eat them. Certainly don’t eat the squishy part…but the rest of the fruit is fine. They can be used in anything from sandwiches to salads to canning. They still taste delicious. If you have animals like pigs or chickens, offer them a change of pace with the bad ends. The pigs will turn all of those nasty ends into delicious bacon and the chickens will reward you with “hen fruit”. Yummmm….

So what has been your experience with blossom end rot this year? Mine has been that it’s a definite problem. Do you have any other remedies or ideas that you’d like to introduce to other Mid-Atlantic Gardening readers? Leave me a comment below or e-mail me. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list (upper right hand corner of this page), become a fan on Facebook and follow me on Twitter. Happy gardening!

 

 

Pests and Diseases: Powdery Mildew

powdery mildew
Photo courtesy of www.ag.utah.gov

Tis the season for the funkiness of powdery mildew to rear its ugly head. It seems that it’s already afflicting peonies, dogwoods and bee balm. All of the usual suspects have a coating of white fungal growth clamoring for space on their leaves. When you hear powdery mildew do you think of cool, wet conditions or dry, warm growing conditions? Let’s take a look at what conditions powdery mildew prefers.

It’s a common misconception that powdery mildew prefers wet leaves when in fact it prefers warm, dry days and cool nights. It loves the days when the humidity is high as that allows the spores to germinate. Once germinated though, it grows like mad when the leaves are dry…wet leaves actually inhibit germination of the spores. After the fungus is actively growing, the spores are spread by splashing water. It’s virtually impossible to not meet all of those growing conditions at some point during the growing season so don’t fret. It’s reassuring to know that most powdery mildews are  plant specific; in other words, the powdery mildew that’s affecting your cucumbers won’t overtake your dogwoods. Do you feel better now?

So what can you do to prevent the likelihood of your ornamentals being infected with powdery mildew?

  1. Thinning – provide enough air movement around your plants so that the humidity doesn’t remain high and allow the spores to germinate. You can accomplish this with perennials by dividing them and planting them in areas with good air circulation. With woody species like dogwood, thin the canopy so that air can move freely. I know of a dogwood that was planted in a courtyard in a building whose leaves are white from powdery mildew all summer long. It’s not a particularly attractive sight.
  2. Resistant cultivars – plant breeders have been working their magic to develop cultivars of plants that are resistant to powdery mildew. Notice that I said resistant…they aren’t magicians so the plants that they’ve developed can still become infected but the infection won’t be as severe. Examples include Cornus florida ‘Cherokee Brave’, Syringa patula ‘Miss Kim’, Lagerstroemia ‘Tuscarora’ and Cucumber Marketmore 76.
  3. Spraying – as you all know by now, I don’t like conventional pesticides and I don’t make recommendations on them here. But what I can offer you is an organic alternative. If you have powdery mildew and would like to prevent it from spreading or are trying to prevent it in the first place, try this concoction: combine 1 TBSP baking soda, 1 TBSP vegetable oil and 1 TBSP dish detergent in a gallon of water. The oil will burn your plants’ leaves if it’s applied during the heat of the day so apply it on overcast days or in the evening. Weekly applications will help deter powdery mildew.

 

If powdery mildew is allowed to infect the new growth on your plants, it can cause distortions of the leaves and even death in some cases. I recommend that you monitor your plants to survey the severity of the disease. If you notice powdery mildew late in the growing season, I wouldn’t bother treating it since the leaves will be dropping soon anyway. I probably wouldn’t bother with treating it all unless it was killing the new growth; but then again, I’m a lazy gardener who believes that the plants will either live or die trying. What has been your experience with powdery mildew? What have you done about it in your garden? Leave me a comment below or e-mail me. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list (upper right hand corner of this page), become a fan on Facebook and follow me at Twitter. Happy gardening!

 

June 12, 2012Permalink 1 Comment

Pests and Diseases: Fire Blight

After a week talking about our Lunatic Tour at Polyface Farms, it’s time to get back to gardening. While I believe that we can learn a lot about gardening from Polyface Farms, I know that you have questions about the plants that you are growing in your backyard. If you have Bradford Pears in your yard, you may be experiencing symptoms that look like this:

fire blight

This picture shows the classic case of fire blight. Fire blight is a bacterial disease that affects Bradford pear trees as well as fruit-producing pears. Its victims can also include apples, crabapples, Pyracantha and hawthornes. Fire blight gets its name from the damage that it causes: it looks like someone has gone around and set the tips of your plants on fire. The leaves turn brown and then black and the affected areas can reach a foot or more from the terminal growth tips. This damage causes a classic shepherd’s hook appearance. Fire blight can also affect the blossoms and they end up turning brown prematurely and dying. Let’s take a closer look at the life cycle of fire blight in order to understand it better.

The bacteria that causes fire blight causes cankers that generally set up shop on the trunks of the trees. These cankers weep and ooze and allow for the bacteria to be transmitted from tree to tree by insects as well as wind driven rain. Sooty mold is often seen growing near the cankers due to their sweet exudate. With the mild winter and wet spring that the Mid-Atlantic Gardening region is experiencing, fire blight infections are a common experience in a landscape still dominated by Bradford Pears. It’s one more reason to remove Bradford Pears from your landscape…or at least vow not to plant anymore.

So what can you do if your trees are infected? If the outbreak is relatively minor, you can prune out the infected branches, ensuring that you remove an additional 8″-12″ of stem below the apparent infection. Dispose of these branches in a landfill or burn them if your local conditions permit it. You can also spray your trees with a bactericide every 7-10 days from bloom time through the spring rainy season but who wants to go through all of that trouble?

The old saying that “an ounce of prevention is worth a pound of cure” certainly applies here. There are many, many varieties of apples, pears and crabapples that are resistant to fire blight. While that doesn’t mean that these varieties will never get fire blight, it does mean that they stand a fighting chance without a lot of fussing over them by you. Resistant apple varieties include Honeycrisp, Jonagold and Winesap. Resistant pear varieties include Honeysweet, Magness and Moonglow. If crabapples are more your style, consider planting Candied Apple, Louisa or Prairie Fire. Consult your local extension agent for other varieties that work well in your gardening area.

If you have experience with combating fire blight in your landscape, please leave me a comment below or e-mail me at stacey@midatlanticgardening.com. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list, become a fan on Facebook and follow me at Twitter. Happy gardening!

 

Pests and Diseases: Cedar Apple Rust

Today’s post is about Cedar Apple Rust. It’s a quite interesting fungal disease that requires two plants to complete the cycle: the Eastern Red Cedar (Juniperus virginiana) and apple trees (crabapples too). Before we get started, let me show what the fruiting body on the cedar looks like…

cedar apple rust

Photo courtesy of fark.com

Isn’t that wild? It reminds of me of the drummer from the “Band” episode of Yo Gabba Gabba. Can you tell that I have a 3 year old?

cedar apple rust

The life cycle of Cedar Apple Rust goes like this:

  1. In the spring, the orange galls form on Eastern Red Cedars. As it rains, the spores are spread to nearby apples and crabapples (Malus spp.). When I say nearby, I mean within a 1/2 mile. As the rains subside in the spring, the galls dry up and no longer spread their spores.
  2. Once the spores land on an apple or crabapple, if the temperature and moisture level are correct, the spores grow and proliferate into orange pustules that are most often seen on the underside of the leaves.
  3. The spores grow there for the rest of the season and then are spread by wind back to the Eastern Red Cedar where they overwinter.
  4. When the temperatures warm the following spring, the cycle begins all over again.

 

Here is a picture of the infected leaves:

cedar apple rust

Photo courtesy of missouri.edu

If the fruit is infected, it can look like this:

cedar apple rust

Photo courtesy of umn.edu

So what can you do to prevent your apples and crabapples from being infected? Unfortunately, not a whole lot. Unless you live in the middle of a large acreage with a half mile around you that can be kept clear of Eastern Red Cedars, you stand a chance of infection. As the saying goes, the best defense is a good offense, so consider planting lots of different varieties of fruit trees. Don’t limit yourself to only apples and crabapples. Depending on what zone you are in, consider planting peaches, figs, paw paws and cherries. The chance that all of your fruit trees will be infected by some fungal disease in the same year are greatly reduced when you have a polyculture. If your apples succumb to Cedar Apple Rust one year, you’ll have other fruits to support you.

If you like what we’re doing here at Mid-Atlantic Gardening, please subscribe to the website to receive updates to the latest posts as well as to be eligible for our subscriber giveaways. You can subscribe by joining our e-mail list on the top right of this page. Thank you for your support! If you have experience with Cedar Apple Rust, leave me a comment below or e-mail me at stacey@midatlanticgardening.com. Happy gardening!

 

March 27, 2012Permalink 1 Comment

Pests and Diseases: Hosta Virus X

 

It won’t be long until your beautiful hostas begin to poke their heads up from their winter slumber. If you have a shady garden, it’s highly likely that some of these plants decorate your garden. They may be hand-me-downs from your grandma or some of the newly bred cultivars. Either way, they could be infected by a virus known as Hosta Virus X.

Many of the hostas that are grown by commercial growers come from Holland where they are grown in large operations. The Dutch are infamous for growing magnificent plants but in any large scale operation, the chances of spreading diseases from plant to plant is increased. Hosta Virus X is often spread when the plants are cultivated or being dug for bareroot shipments. As the machinery works the rows, plant leaves are damaged and the juice from one plant is spread to the open wounds of the next. This is how Hosta Virus X is spread.

WHAT ARE THE SYMPTOMS OF HOSTA VIRUS X?

Hosta Virus XThere is a typical virus pattern on the leaves with strange mottling and weird patterns that are not usually seen on the hosta in question. The leaves can be mottled and strangely wrinkled. Before this Hosta Virus X was discovered, many breeders thought that they were onto something new. The mottling was interesting in appearance so the plants were thought to be new and unique. Unfortunately, it was Hosta Virus X that was causing these “neat” new looks.

WHAT CAN YOU DO IF YOUR PLANTS ARE INFECTED?

Unfortunately, it can take years for the virus to rear its ugly head but when it does, the plant needs to be destroyed immediately. Testing for the disease isn’t practical and generally once you have seen Hosta Virus X it is easy to spot the next time. After you’ve dried your tears from pitching some of your favorite hostas, make sure that you don’t infect the rest of your plants. As we talked about earlier, Hosta Virus X is spread by transferring plant juice (doesn’t that sound scientific?) from an infected plant to another hosta plant. Make sure that you take every precaution to not infect your clean plants: wear gloves, bag and dispose of infected plants, and clean your tools well.

I found a great resource online that details Hosta Virus X and the varieties that it is commonly found on. Let me know if you have any experience with this virus…something tells me that many Mid-Atlantic Gardening readers do. Leave me a comment below or e-mail me at stacey@midatlanticgardening.com. Happy gardening!

 

 

February 21, 2012Permalink Leave a comment

Pests and Diseases: Gray Mold (Botrytis cinerea)

 

Today we will be discussing a fungal disease known as Gray Mold or Botrytis cinerea. I’ve always called it by its latin name, Botrytis (pronounced BO-TRY-TIS), so forgive me if I go latin through most of this post. Botrytis is a fungal disease that can infect just about any crop, although herbaceous plants like perennials and annuals seem to be the preferred choices. Many people think of botrytis as a greenhouse problem, and while it certainly can be, it can also affect your outdoor plants.

It is often found on plant material that has been killed by frost but hasn’t been removed from the landscape. The plant that sticks out in my mind is balloon flower, or Platycodon. At the nursery that I used to work at, we would lose Platycodon by the hundreds if we didn’t remove the foliage soon after the first killing frost. Once the foliage is dead, it tends to accumulate moisture and that moisture breeds botrytis which infects the crown and ultimately kills the plants.

SO HOW DO YOU KNOW IF YOUR PLANTS HAVE BOTRYTIS?

If you see a fuzzy gray mold on your plants when the weather conditions have been cool, cloudy and damp, chances are that you have botrytis. If the infestation isn’t particularly bad, you can remove the infected foliage (I don’t recommend composting it; I would trash it instead) and your plants should be OK come spring. I prefer to take a wait and see approach instead of going through the trouble of worrying myself whether the plants will survive. In the case of Platycodon, they are pretty prolific self seeders so you should have little babies that you can transplant to fill in any holes.

OTHER PLANTS THAT CAN BE AFFECTED BY BOTRYTIS

Peonies are probably the most well known as they are prized for their large flowers that appear in the spring. Unfortunately, botrytis can attack the buds before they open and lead to a display of black buds instead of beautful flowers. If your stems turn black from the bud down, botrytis is probably the culprit.

If you are a fan of Forget-Me-Nots, or Myosotis palustris, you may find that the centers of your plants open up and when you peek inside, there’s a colony of gray mold that has taken over…if that’s the case, you can bet that it’s botrytis.

Many, many other ornamental plants are susceptible to Botrytis including petunia, cyclamen, chrysanthemums and annual geraniums. Fortunately for the gardener, most of these disease problems occur in the greenhouse industry where plants are grown at intense densities.

WHAT CAN YOU DO TO PREVENT BOTRYTIS?

Botrytis is spread by splashing water so it is imperative that the foliage has a chance to dry before the coolest part of the day occurs. In an outdoor setting, it is unlikely that you will have to water your plants when the cool, cloudy, damp conditions exist, but on the off chance that you do, be sure to water in the morning.

Sanitation is by far the best way to prevent your plants from becoming infected with botrytis. In the fall, remove foliage that has been killed by the frost and give your plants enough room so that air can get in to dry the foliage in the spring. Once the weather decides to stay warm, botrytis will be a thing of the past. Let me know if you have had problems with botrytis in the past and what you have done to remedy the situation. Leave me a comment below or e-mail me at stacey@midatlanticgardening.com. Happy gardening!

 

January 3, 2012Permalink 1 Comment

Pests and Diseases: Damping Off

 

Picture courtesy of UConn

With all of the talk about starting seeds for your veggie garden, I thought that it would be appropriate to look at a disease known as “damping off” that can affect your seedlings. Damping off is a catch all term that is used to describe what happens to seedlings when they essentially rot right at the soil line and fall over. Damping off can also occur before the seedling emerges from the soil, but the most common form of damping off is when the seedlings’ stems turn black at the soil line and fall over. It can be caused by many soil-borne fungi including Pythium, Sclerotinia, Phytophthora, Rhizoctonia and Botrytis. Needless to say, damping off is fatal to the young seedlings.

WHAT CAN YOU DO TO PREVENT DAMPING OFF?

Perhaps the easiest way to prevent damping off is to use clean potting soil when starting your seeds indoors. I’m a huge fan of compost but I generally start with a pre-packaged sterile potting soil. Once the plants make it past the seedling stage, they aren’t susceptible to damping off so it’s OK to topdress them with compost then.

Another key preventive measure is to keep the seedlings dry. That doesn’t mean that you can’t water them…it just means that you should only water them when they need it. I have found through the years that gardeners tend to love their plants to death…the usual means of killing them is through overwatering. With seedlings, it is especially helpful if you water them from the bottom. Fill the tray with water and allow the plugs to absorb the water for a few minutes. After a few minutes, dump the excess water out so that your plants don’t drown. Many seed starting kits come with a little plastic dome that you can use to create a little miniature greenhouse effect. I have found that it is best to either leave the domes off or at least prop them up…otherwise the potting mix tends to stay too wet and that invites damping off.

Getting the plants growing vigorously can also prevent damping off. If you don’t have a greenhouse, place your grow lights as close to the seedlings as possible to get them up and growing. When I say close, I mean close…1″-2″ from the tallest seedlings is perfect. Otherwise, the seedlings become tall and lanky and literally grow themselves to death. They use up all of the energy that is stored in the seed trying to get tall enough to reach the light. That’s a pretty pitiful way to die if you ask me. Don’t fertilize them until they are larger…otherwise they’ll grow too fast for their roots to keep up with.

Air circulation is key to preventing damping off too. That’s another reason that I don’t like those little greenhouse domes. If you are starting your seeds in your house (as I do) then the normal amount of air circulating from your heating system should work just fine. Otherwise, set up a little oscillating fan several feet from your seedlings…just be sure to keep a close eye on your seedlings as they are more prone to dry out this way.

Use clean, sterilized containers when starting your seedlings. In the past I have used the Jiffy pellets but they are pretty expensive. This year, I’m hopeful that I can purchase a Soil Cube. It’s a great value for the price and once I have it, I won’t have to buy those little pellets ever again. Either way, I’ll still have to put the the pellets or soil cubes in something, so it is imperative that it be clean. I re-use my plastic flats year after year and they are stored outside during the summer months. All I do is knock the debris out and soak them in a bleach solution in my kitchen sink. I guess I should measure how much bleach I use, but I don’t. I just pour a good amount of bleach into the sink and add water to cover the flats. I usually let them soak for 5 or 10 minutes (or longer if I get distracted) and then rinse them with clean water. They are then ready to use.

WHAT CAN YOU DO IF YOU HAVE DAMPING OFF IN YOUR SEEDLINGS?

Unfortunately, all that you can do is pitch them. I know that seems devastating but hopefully you can eliminate the pathogen before it decimates the rest of your seedlings. If you are growing your seedlings in flats, it is best to pitch the infected ones and move the remaining seedlings to another sterilized flat. If any of the soil from the infected seedlings is touching its neighbors, it would be prudent to pitch the neighbors as well. Better safe than sorry!

I hope that you have gleaned some helpful information from today’s post. The most important thing to remember is that there are setbacks that can happen in any endeavor. Don’t be discouraged if you have problems with damping off. Professional growers experience this same disease but yet they keep on growing plants. Just eliminate the infected plants and sow some more seeds to replace the ones you lost. You will be rewarded time and time again when you are harvesting the fruits of all your labor this summer. Let me know if you have had any problems with damping off. Leave me a comment below or e-mail me at stacey@midatlanticgardening.com. Happy gardening!

 

December 27, 2011Permalink Leave a comment

Pests and Diseases: Rose Rosette Disease

 

It is with great sadness that I discuss our topic today: Rose Rosette Disease. You see I fear that the glorious Knockout series of roses may follow the same doomed fate as that of the ubiquitous red tips (Photinia). As I’m sure that you’re aware, red tips have been planted ad nauseum in millions of landscapes around the country; when one particular species is planted in such quantity it is referred to as monoculture. When monoculture occurs, it is very easy for a pest or disease to come in and decimate the overplanted plant. In the case of red tips, a fungal leaf spot known as Entomosporium is the culprit. In the case of my beloved Knockout roses, the causal agent is a virus known as Rose Rosette Disease.

WHAT ARE THE SYMPTOMS OF ROSE ROSETTE DISEASE (RRD)?

If you’re like me, when I check Web M.D. or another medical website, I like to skip right to the symptoms to see if they fit my particular ailment so that’s what we’ll do here. By far and away the most tell-tale sign is a witches broom appearance on the new growth. If you’re not familiar with what a witches broom is, the best way I can describe it is it’s like a really compact, version of the plant itself. Here is a picture that is on the Virginia Cooperative Extension website in case my words didn’t do the description justice. Often times the witches broom is bright red in color on the Knockouts and resembles a bouquet of flowers. Another give away symptom is that of excessive thorniness and extremely flexible new growth…so flexible that you can tie a knot in the stem. If you see either or both of these symptoms, you can rest assured that you have the dreaded Rose Rosette Disease.

 

SO WHAT CAUSES ROSE ROSETTE DISEASE?

There is a tiny, microscopic mite that is 1/100 inch long that is known as the eriophyid mite. It is this rinky dinky little arthropod that threatens to remove the Knockout roses from my gardening palette. Notice I said my garden palette, not the garden palette. These mites transmit the virus that cause RRD…now take a guess how they get from one area to another. They blow along in the wind or hop a ride on an unknowing bird or insect. The frustrated part of me thinks “how am I supposed to fight that? Should I put a bubble around the roses or stick them in a vacuum chamber?” Realistically, all you can do is hope that this miserable little mite doesn’t find his way into your garden.

WHAT CAN YOU DO TO LESSEN THE CHANCES OF RRD AFFECTING YOUR ROSES?

  1.  Buy clean stock. Even if you see a killer deal at the end of the season in your garden center, don’t buy it if you see any of the above mentioned symptoms.
  2. Work cleanly. When pruning your roses, sterilize your pruners often and certainly between shrubs. RRD can also be spread by pruning cuts so make sure that you take care not to inoculate your own shrubs with this lethal disease.
  3. Avoid planting cultivated roses near areas that contain the wild multiflora roses. Your approach could be to remove the wild roses as they serve as inoculum for the disease. Or if you know that wild multiflora are in the area, you could avoid planting the Knockouts at all (that thought makes me sad).
  4. If you observe RRD on your plants, you must remove and bag the infected roses. Don’t try to compost them or let them ride in the back of your truck on the way to the landfill…you’ll just be spreading your misery to other gardeners who live along the path to the landfill.
  5. There’s always chemical control but that’s not a philosophy that I really buy into. My theory with plants is that they will either live or die trying. To me, it’s easier to just remove the roses and count your losses.

 

I should note that RRD affects other types of roses but I’m most concerned about the Knockout roses. They are an absolutely delightful plant to cultivate and they reward you many times over what you invest in them. I am as guilty as the 1990’s landscaper who installed red tips at every job. I use them in almost every landscape I design and I realize that I need to curb my enthusiasm so that I don’t add to the monoculture of Knockouts. But it’s a really hard plant to replace…what other shrub blooms from April to December, doesn’t require spraying, and is as beautiful as a rose? If you have any ideas, please e-mail me at stacey@midatlanticgardening.com or leave me a comment below. Happy rose gardening!

December 6, 2011Permalink 16 Comments

Reader Question: Japanese Holly

 

I received the following question and thought that it would be useful for all of you to know as well:

Hi Stacey. I have Japanese hollies as my foundation planting on the front of my house. They have been developing brown, dying to dead areas and I’m concerned that there is something wrong with them. I noticed that my annual vinca plants that were planted in the same bed didn’t do well this summer either. Sorry I don’t have any pictures but I’ll try to get them to you soon. Do you have any ideas as to what this could be?

Steve

Photo courtesy of Virginia Cooperative Extension

Steve, first of all thanks for e-mailing me…this is exactly the reason that I started this blog; to help gardeners solve the problems that they are experiencing. With that being said, I’m afraid that I don’t have any encouraging news to offer. I’m pretty sure that black root rot (Thielaviopsis basicola) or BRR for short, is to blame. Japanese Holly is otherwise known as Ilex crenata and the entire crenata species falls prey to BRR. Annual vinca (Catharanthus roseus) is also on the list of plants that BRR enjoys. While chemical controls are always an option, I’m not a fan for many reasons. My advice is to remove the shrubs and take as much soil with them as you can; in other words, don’t shake the soil from the rootball as you remove them.

Black root rot is ubiquitous which means that it is virtually everywhere. When viewed under a microscope it looks like little Tootsie Rolls in the soil.

Photo courtesy of Virginia Cooperative Extension

Those “tootsie rolls” are known as chlamydospores and there sole purpose in life is to remain dormant until the next little root comes growing by. At that point, the infection starts all over again.

But there is good news from all of this…there are many plants that are resistant to BRR and can grow very well in areas that have been contaminated. Some of the shrubs include Nandina, Chinese holly (Ilex cornuta) and Boxwood (Buxus spp.). If you are looking for annuals that can tolerate a BRR infestation, consider Mexican heather (Cuphea spp.) or Lantana but steer clear of vinca, petunia, pansies and geraniums (Pelargonium).

I hope this helps you Steve and anyone else who may have Japanese hollies that are floundering in the landscape. This speaks volumes about monoculture but I’ll save my time on my soapbox for another day. If there are any pest or disease issues that you’d like me to help you with, please let me know at stacey@midatlanticgardening.com.

November 22, 2011Permalink Leave a comment