Category: Disease

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What to do about creases in gladiola leaves?

TheGardenLady received this question from Jim.

The leaves on a number of my gladiolas have developed a bend or a crease, often when they are nearing blooming, from which they never recover. This is so maddening! Yep, at about the halfway point in the long leaves, they just droop over, usually developing a crease, and the plant never blooms. ‘I’ve actually tried to “splint” these plants, to no avail. This usually occurs when the leaves are forming that “fan” shape from the bottom upward, when the plant is about to form buds.It’s like “so close, yet so far”. Would appreciate some input.

Though I hate planting bulbs each year, I love gladiolas and am willing to do the extra work finding spaces to put them in my garden.

But like all plants glads can have diseases. Since TheGardenLady has not seen your plants, from your description it sounds like the corms of your plants are infected with what is referred to as Fusarium rot and yellows.

Here is what the University of Minnesota Extension has to say about the disease:

Corms infected with the fungus  oxysporum f.sp gladioli may produce symptomatic plants or develop dry rot in storage. Plants growing from infected corms may develop arching young stalks or premature yellowing of leaves and faded flower colors. Often plants are stunted and fail to bloom. The corm rot, not always visible externally, is often restricted to the corm base. When the corm is split in half, there may be dark-colored streaks that extend from the corm base through the flesh. In storage, corms may develop dark spots on the surface or in severe cases the entire center may be black and decayed. Management includes removal of infected plants and corms with obvious decay. Follow good harvesting and storage procedures. Fungicides may be used to dust corms before planting. The use of high nitrogen fertilizers tends to increase corm rot development.

If this description fits what you are observing with your plants, dig them up and discard. Do not compost. If this description does not fit what is happening to your plants, take the entire sick plant, include the corm, to your local Master Gardener office for them to ID the disease.

Next year if you decide to plant more gladiolas, this GardenLady would buy new corms from a reliable source and plant these new corms in different locations than were planted this year.

One source for Gladiola bulbs* that looks interesting that this GardenLady wants to try is Heirloom Gladiolus Bulbs.

*corms are referred to as bulbs by most people

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Hosta Problems

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DSCN1353

TheGardenLady received this question from Pete (You can see images of his hostas above):

I have many green hosta plants that for the last couple years have wilted leaves or are otherwise distorted.The plants are quite old but were always healthy till now. Any ideas?

Though hostas are known to have few pest and disease problems, sadly they do develop some diseases and do get some pests. Some of these
problems may not kill the plant but makes them look unattractive. I have a feeling that your problem is not a killer.

You do not say where you live, but in many areas of the US, this spring has had a lot of rain. Some diseases need the excess moisture
to cause problems. This excess moisture on the plants is either through excessive rain or excessive overhead watering.

Continue reading “Hosta Problems”

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Avocado Tree Problem

TheGardenLady received this question from Tricia.

About a month ago I transplanted 2 young avocado trees (bought at the local nursery) into large containers (their spots in the orchard aren’t ready yet). I had watered them 2x/wk week in the beginning and then 1x the following week because the soil was staying wet and I was afraid there wasn’t enough drainage. One of the trees’ leaves started yellowing, even though it gave me flower buds already. So I stopped watering it, afraid that’s why it was yellowing (the other one is fine). It now has all the upper leaves completely yellow and some turning brown and curling. The lowest ones are still green. I’m not sure what to do? Water it or not? The soil still appears moist.

Fungus is the most serious disease of avocado trees, which may be the problem of your avocado tree. As you wrote, you over-watered the plant and also the plant might have had poor drainage in the pot you put it in. You should take your plant to your nearest Agriculture Extension
office for an accurate diagnosis. They can offer you, for a fee, lab tests and soil tests to see if your tree has a fungus. (see here)

It is difficult to diagnose the problem from just a brief paragraph. Here is what UCDavis has to say about avocado diseases.

 

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A Sick Peace Lily

TheGardenLady received this question from Mary.

I have a diseased plant. I believe it’s a peace lily. It was given to my family after my grandmother passed away and once it became diseased my mother wanted to throw it out but I wanted to try to save it; so I brought it to my house in San Diego. Do you have any suggestions on how I can save it? Almost every leaf is dark and wilted, starting from the tip and moving to toward the root. The part that meets with the soil is turning yellow. Can I send a picture?

TheGardenLady knows how meaningful it is to try to keep something that is inherited from a beloved relative. And plants are treasured for those dear memories. So of course, you can send a photo of your plant. A photo can often help more as a diagnostic tool than just a verbal description.

But even better than sending the photo to TheGardenLady, is to take your plant to your local Master Gardener office for them to see the plant and, hopefully, to recommend a way of saving it. This is a free service with people trained in horticulture who work as a group to diagnose this very type of problem. Here is the website of the San Diego Master Gardeners with a telephone number to call and ask a good time to bring your plant in.

Though Peace Lilies, Spathiphyllum, are quite hardy and easy to grow, they do get some diseases like root rot and bacterial soft rot.

Therefore, even without seeing your plant, this Garden Lady would suggest your taking the plant out of the soil it is in and seeing if there is root rot. If there is, cut the rotten root out till you see healthy root- hope it is not too late. Cut back dead leaves but leave any healthy looking leaves or even green segments of leaves. Wash off any remaining soil left on the root and wash the leaves using cool water.  Then re-pot the lily in either a soil-less potting mix or a regular soil-based potting mix that you can buy in any store or make your own soil. It is important that the soil drains well. Directions for soil (here).  Water the soil and give the plant some fertilizer. Never water too much because the Peace Lily plants hate being in soggy ground. Do not give too much fertilizer because these plants prefer getting their nutrition from good soil – directions for this type of fertilizer and watering instructions are also in the article.

If you grow the Peace lily indoors, put the newly re-potted plant in BRIGHT INDIRECT light – that means no sun shining on them.  If you grow the plant outdoors, it likes moist but well-drained hummus-rich soil in shade.

If your Peace lily does have a disease, the Master Gardeners will tell you and will recommend a fungicide.

Good luck. I hope it is not too late to save your grandmother’s plant.

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Black Spot on Roses

Black spot of rose Scot Nelson

TheGardenLady wrote about the roses in her garden that get black spot.  Many roses, unfortunately, are affected by this disease. As I had written, one is never to water roses overhead. Mechanical watering devices that come on automatically at a set time are especially problematic in overhead watering. TheGardenLady has seen blackspot in some major rose gardens or botanical gardens that do overhead watering. Also, one should water in the early morning hours so that hopefully water will dry or evaporate from the leaves later in the day. Do not water in the afternoon. Always let the water run near the base of the rose. A soaker hose might be best.

But what should one do if it rains? Mother Nature sends the rain from above at any time of the day or night. And if it is a particularly rainy season, that is when you can usually see a lot of black spot on the rose leaves. Sometimes the black spot can get so bad that it can defoliate the roses to make the plant look unsightly even though the flowers look attractive.Then without leaves, the plant gets sickly and is susceptible to other disease or problems. So what should one do?

Continue reading “Black Spot on Roses”

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Plant Diseases, such as Boxwood Blight

Boxwood Blight – Photo taken by Kelly Ivors

One of the frustrations with gardening is the number of diseases plants get. And with the changing weather patterns, we seem to be getting diseases on plants that we never had in certain locations or diseases that are new. TheGardenLady is not a plant doctor. She always recommends that if you see a disease on your plant, that you cut a good sized sample of the plant with the diseased part- cut it all the way back and include some of the healthy specimens with the diseased part when you take a sample- you want a a big sample. Take this sample to your local Master Gardener Office or to your local extension office for them to ID and tell you how to correct the problem or if you should get rid of the plant so that it does not infect other plants. They will also tell you if you should trash the plant or compost it. Some diseases you do not want to put in your compost pile.

They will ask you a series of questions such as the name of the plant. (If you don’t know it, don’t hesitate to tell them you don’t.) How old the plant is. What direction it is growing on your property N,S, E, or W. Any changes to the area where it is grown. Did it get any pesticides or chemicals on it- like ice melting substances? To make a good diagnoses it is best to have a lot of information.

Continue reading “Plant Diseases, such as Boxwood Blight”

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Pyracantha Shrub Diseases

Firethorn, Pyracantha, little yellow berries on bush, NC 280 and old NC 280 by Martin LaBar (on hiatus)

TheGardenLady received this question from LaNelle.

You have named several pests/diseases of pyracantha: Mine suddenly have limbs dying in the middle of limbs/trunks. These are established bushes for privacy fence. How can I save them?

There are a number of different diseases of the pyracantha shrub.  See here or here.

One disease is called Fireblight. Fireblight is a systemic bacterial disease which is spread by aphids, bugs, birds and even the wind and rain. It can kill the plant. Fireblight is easily spread and can quickly spread from plant to plant. The disease is easy to spot. Affected leaves start to turn black and cracked as if they have been burnt by fire, giving it its name Fireblight. It causes the dieback of stems and leaves. Bacterial ooze often is associated with blighted tissues.

Continue reading “Pyracantha Shrub Diseases”

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Gardeners in the Northeast: Beware of Late Blight

Late blight of potato by Ben·Millett
Late blight of potato by Ben·Millett

The following article was not written by TheGardenLady, but she thinks it’s a valuable one that the public should know about.

Irish Potato Famine Disease affecting Gardens and Farmers throughout the Greater Northeast

Revised by A. Wyenandt, NJAES, Rutgers University and M.T McGrath, Cornell University – Original article by Thomas A. Zitter, Cornell University, Ithaca, NY – Updated July 15, 2009

Late blight, caused by Phytophthora infestans, is a serious disease that affects tomato plants and potato plants around the world.

late blight by ospud late blight by ospud
late blight by ospud late blight by ospud

Late blight can become a serious problem because it can quickly kill affected plants and its spores are easily carried in wind currents to infect other susceptible plants in even the most remote areas in our region.

Late blight occurs sporadically in the Northeast in any given year because farmers diligently use methods to prevent the pathogen from surviving overwinter. Since our summer thus far has been cool with frequent rains, weather conditions have been very conducive for late blight development.

Late Blight on Plum Tomatoes by Franknsteen
Late Blight on Plum Tomatoes by Frank'nsteen

Currently, all tomato and potato plants grown in home gardens and in commercial fields are susceptible to late blight!

Commercial growers are able to respond to reports of the disease by spraying fungicides to prevent its spread, which otherwise would mean certain death of their entire crops. Unfortunately, many homeowners may not be as aware of this important disease, and if no corrective actions are taken in a timely manner, home gardens can provide a source of inoculum (i.e. spores) for their neighbor’s gardens and for commercial interests.

The occurrence of late blight in 2009 is different compared to most seasons. This is the earliest the disease has been reported over such a broad region of the country. More tragic for the Northeast, is that infected plants have been distributed to large local retail stores throughout the region (Ohio to Maine). Never before has such an extensive distribution of infected plants occurred.

Continue reading “Gardeners in the Northeast: Beware of Late Blight”

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Marigold Mystery

Dying Marigold by interchangeableparts
Dying Marigold by interchangeableparts

TheGardenLady received this question about marigolds.

My marigolds are planted around the edge of the garden and watered 2x a week with the rest of the garden.  After a month they just started dying with no visible infestation.  Do you have any idea why?  Last year I planted marigolds in the same vicinity under a citrus tree and they survived just fine.  The plants were bought at Lowe’s garden center both times.

Marigolds are one of the easiest plants to raise. But like any living thing, they can have problems.  See here.  You write that you bought plants at the same local store that you bought them last year. Last year they might have been healthy but this year you might have bought home unhealthy plants- for example, the pots may not have been watered property and you might not have noticed that they looked sickly.

We are lucky to have inexpensive garden centers to buy plants, but many times these stores cannot find knowledgeable people to work in the nursery, people who know how to properly maintain the plants they sell. In the tiny pots the plants come in without proper watering, the roots might have dried out. Or the plants might have had a fungal or bacterial problem in the soil.

Marigold by floridapfe
Marigold by floridapfe

You said that you planted the marigolds in the same vicinity as you planted this year. There can be differences in areas that are close by. For example, in my area in my soil we have lots of shale. A part of the ground close by can have larger rocks down below that doesn’t allow for good drainage in one spot but just a few feet away it is fine.

You said that you watered the plants 2 times a week. Not seeing your marigolds, this seems to TheGardenLady to be what caused the death of your marigolds this year. Marigolds may like a little water when the plants are young-if you raised them from seed. But you bought the plants. After the first watering when you planted them, they really don’t want or need to have you water them unless there is a 10 day or 2 week drought. Perhaps the plants in the border that you put the marigolds in need watering twice a week in the area you live, but this was probably too much water for marigolds. Marigolds like to be in dry soil. They don’t like to sit in wet soil and they don’t like overhead watering. When you water them, they prefer it if you use a soaker hose.   See here.

Dig up the dead plants and discard. Replace them with plants that need as much water as the other plants in your border. How will you know which plants are best? Go to a smaller, local nursery where the people who work there are plant lovers themselves. There are many of these small nurseries in every area. Ask questions when you buy the plants. Tell them what other plants are planted near by to see if the new plants you are buying are compatable.

calendula-şamdan çiçeği by NURAY YUZBASI
calendula-şamdan çiçeği by NURAY YUZBASI

TheGardenLady has written other posts about problems with marigolds and caring for marigolds.  Check them out here and here and here and here.   Hope you solve your marigold mystery.

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Gladiolus Leaves Turning Yellow

Plant turning yellow is an early symptom of Fusarium
Plant turning yellow is an early symptom of Fusarium

TheGardenLady received this question from Diane.

I planted some Gladiolus bulbs in the spring and they were coming up beautifully. Today I noticed the leaves on one of them were turning yellow. I haven’t had any bloom yet but the stalks were very green and hardy. What can I do for this plant? Why would it have turned yellow?

Gladiolus grow best in loamy soil with proper drainage. Glads do not grow well in soil that is too wet. Soggy, compacted soil hampers root growth, diverts moisture and locks up plant food. Glads need plenty of water. Lack of water inhibits spike growth, flower development and corm growth. Watering at planting will help develop a good root system. Provide at least one inch of water each week to ensure good growth, making sure the water soaks 6-8 inches into the soil.

Not having seen your gladiolus, I cannot give the most accurate reason for why your one gladiolus is turning yellow. Gladiolus are very hardy and have few problems. But all living things do HAVE problems.

You may have bought a corm, or what you call a gladiolus bulb, that was deceased. There are a few root rots or corm rots that fit the description of gladiolus getting yellowing leaves.

From the University of Minnesota extension they write,

Stromatinia Corm Dry Rot – This corm disease, caused by the fungus Stromatinia gladioli, is found during periods of cool, wet weather. Leaves produced from infected corms turn yellow prematurely and die. Small, red-brown, sunken lesions develop on the corms. When an infected corm is cut in half, dark streaks can be seen radiating out from the core to the surface of the corm. The fungus produces sclerotia (over-wintering structures) in infected tissue. Often plants are infected in groups as the fungus spreads from the original infected plant. To manage this disease, discard infected corms, plant only healthy corms in well-drained soils and in the fall harvest corms during dry weather. T. Do not replant gladiolus corms in infected soil.

Or another corm rot described in a professional gladioli website is Fusarium oxysporum f. sp.gladioli . During the growing season, leaves turn yellow prematurely and stems collapse. During storage, corms develop a reddish-brown dry rot. Diseased corms produce spindly, weak plants the following year.

Because corms are inexpensive, it would see best to pull up and discard the one plant that looks yellow and hope that if there is a disease, it has not spread to your other gladioli. Never plant another gladioli in the spot where the infected corm was.