UACES Facebook General Information

General Information

(September 2015)

 

Question

I have some Gerber daisies in clay pots on my back porch, they have been beautiful and bloomed often.  Just last week the leaves on the plant have all developed what looks like a fungus on the leaves.  I have sprayed Bayer Advance with no improvement.  Could you tell me what causes this condition and what to do about it?  I have enjoyed the plants for two years.  They were in the garage during the winter and even bloomed there.

 

Answer

Don’t expect immediate results from fungicide sprays.  Diseases don’t happen overnight, and control won’t either.   Spots won’t disappear with spraying, but new growth should come out that is healthy.  You don’t mention exactly what is happening, but if you have powdery mildew –a white growth on the foliage, that can occur with periods of high humidity.  If it is leaf spots, plants that get stressed can have some this late in the season.  Gerber daisies are considered relatively short-lived perennials if left outdoors year-round.  If only a few leaves are affected, remove them.  Lightly fertilize, since the plants have a good couple of months of growth left before you move them back into the garage.  Let them dry out a bit in between watering


 

(December 2012)

Question I have a question about some trees in my yard.  I have a number of post oaks in my yard, and I am finding a growth of some sort on the underside of many of the leaves.  I have attached a photo.  Can you tell me what this is and whether it is a problem that needs to be treated?  There are many of them, and I don’t find them often on oak leaves from other yards.  I live in Fayetteville.

 

AnswerYou have a gall on the leaves.  Galls can look frightening, but cause little damage, when on leaves. They can be hard shelled or fuzzy, and some even come with polka dots! Galls can be caused by insects or a fungus, but in this case it is caused by a small mite.  They are nothing to be concerned about. Occasionally different species of galls form on small branches or twigs, and these can do harm, but yours is common on trees everywhere.


(July 2012)

QuestionI have tomatoes in size ranging from dime size to silver dollar size.  A large number of these tomatoes have dark brown and/or black areas at the bottom of the tomato.  What is causing this and what can I do?

 

AnswerBlossom end rot has started in our gardens.  Although it looks like a disease, it is actually a calcium deficiency which affects some varieties more than others.  It often hits our gardens when it has been really dry and we get a downpour of rain.  Fluctuating water levels make it much worse.  Try to mulch your garden and keep it as evenly moist as possible in these dry days.  There are some calcium sprays like Stop Rot or calcium chloride which can help, but even watering and mulch should also do the trick.  It won’t correct the tomatoes that have the problem, but should prevent more from succumbing.

QuestionMy oak tree has some round ball things attached to the underside of some leaves.  Do you have any idea of what this is and how I should control it?  Will it kill the tree?

 

AnswerThe problem is a gall.  Galls can be caused by insects or diseases, but more commonly on oaks they are insects. They can be very showy—some even have red polka dots.  They come in all colors and sizes and if only on the leaves I would not worry about them.  There is an oak gall that can attack some trees that can cause damage, but it gets on small stems and twigs, not on the leaves.


(June 2012)

QuestionI had a beautiful Lilac Bush that was just gorgeous Easter day. It had more blooms than it ever has. We planted it 6 years ago. It came through the summer heat last year just fine, and then within two weeks after Easter, the bush was dead.  The leaves were all dried up and curled. No sign,  that I could see of bugs. Could you tell me what could cause this? I have another lilac bush 30 feet away, and it is fine so far.

 

AnswerThe fact that it died so quickly indicates something has either killed the roots or girdled it at the soil line.  It could be either a root rot or borers. Check the plant at the soil line for signs of borers, holes in the stem.  If you have a heavy soil and it got overwatered it  could be a root rot. When you remove the plant, check the root system. Is it full and white, or black and slimy?  Is there any odor?  These are all indications of root rot.  If you still can’t determine any cause, take it to your local county extension office to send to our disease diagnostic lab.


(April 2012)

QuestionOur family moved into a new house in January.  We have a tree in our landscaping near the house, and I'm not sure what it is.  The parts that are blooming and leafed out look healthy and pretty.  However, there are several branches with nothing on them.  I'm not sure if I should go ahead and cut those branches out now, or if I should wait until after it's done blooming.  If I cut them all out, there may not be much left.  Also, do you know what could have caused this?  There doesn't seem to be any fungus or pest on it anywhere that I can see.

 

AnswerThe tree in question is a flowering cherry.  They are one of the most beautiful spring flowering trees, but not the longest lived in our area.  The trees are susceptible to a host of insects and diseases, with borers being quite common.  The fact that your house was for sale probably during last summer, could also have played a factor. If it wasn’t watered as well as it could have been, that would have stressed it even more.  I would go ahead and cut out all the dead wood, enjoy what few blooms it has and then shape those branches to see if you can restructure the tree.  Once it is bad as yours is, probably an easier alternative would be to plant another tree nearby and remove this one eventually.


(Feb. 2012)

QuestionI know it's hard to tell from a photo but my magnolia is sick. The leaves are falling off and the remaining leaves are turning yellow and limbs with no leaves. There appears to be a scaly grayish fungus growing on most limbs. Is there a treatment for his condition?

 

AnswerI can tell by the photo that your tree is sick.  The foliage is yellow and there isn't near enough of it. Did you water this past summer?  You may have scale insects, but to determine what you have, take a branch in to your local county extension office.  As old as your plant is, and as scrawny as it has become, I don't know what kind of turn-around you are going to have, but let’s get it diagnosed and if it is insects, we can handle that, start fertilizing this spring, water and see what happens.


(November 2011)

QuestionI have a mysterious fungus on my bush known as the burning bush. It had little apples on it first, when they fell off the fungus appeared.  Do you know what could have caused the fungus to grow?

 

AnswerIt is not a fungus but an insect called wax scale.  The wax scales are one of the larger scale insects with a white waxy coating which protects the insect.  Prune out any branches that are covered in them, and then spray with a dormant oil after all the leaves have fallen off.  Dormant oil works by smothering out the insects, so thorough application is necessary.  Dormant oil is a good approach on deciduous plants because you can get good coverage.  With evergreen plants it is difficult because the leaves are dense which makes coverage more difficult.  You can also use a systemic insecticide containing Imadicloprid in late winter. Be aware that once dead, the scale will not fall off the plants, but the large white ones will turn a dull gray color.

QuestionI have a twelve year old Henryi clematis that was diagnosed this past summer with Clematis Wilt.  They recommended that I cut it all the way back to the ground and said that it would possibly come back in the fall.  It did and looked healthy for about a month and even sent out one new blossom.  However, now the leaves are starting to brown on the edges just like it did during the summer. I suspect that the browning is the "wilt".   Your thoughts would be appreciated.

 

AnswerI would be very surprised if clematis wilt were showing itself again this late in the season. I would suspect it is natural leaf drop for the winter.  Clematis wilt is tricky.  It tends to be worse on large flowered forms and in heavier soils.  Sometimes transplanting it to a new location and planting it high can help.  In some varieties, this disease occurs annually killing it to the soil line for several years, and then the plant seems to outgrow it and you never get it again.  I am surprised it just hit yours since it is 12 years old and I am assuming in the same location. Good luck.

QuestionI have several 'Otto Luyken’ laurels in my front yard that look like they have taken a beating. They face east and get early morning sun, which was pretty brutal this year, although I watered pretty regularly. It also looks like some kind of insect has been eating them. One of the bushes has dead branches on one side, so I've been trimming that one. I guess my question is, are they goners, or will they perk up in the spring? They are a significant part of my front landscaping, so I sure would hate to lose them.

 

AnswerA lot of plants took a beating this summer, but for now, leave them be and see what happens next spring.  As they begin to grow in the spring, assess how much damage was done, and if they are greening up, consider corrective pruning then.  There is a disease known as shot hole fungus that causes tissue to fall out and leaves perfect holes in the leaves.  Don’t spray now, let’s just see what happens in the spring.


(December 2011)

QuestionMy azaleas are turning yellow. Is this a disease or deficiency of some kind?  I have several varieties and all are turning yellow.

 

AnswerLook around at other yards and you will see you aren’t alone.  This is a common problem every year.  Even though the azaleas are evergreen, they shed old leaves annually.  Light pink and white azaleas turn yellow before their leaf shed, while darker flowering forms usually turn reddish shades.  It looks alarming since it is so all encompassing, but if you look closely, the leaves closest to the tips of the branches and the flower buds are still intact.


(November 2010)

QuestionWhen I plant my tomatoes in the ground they start out pretty good for the first two weeks. Then when they start coming up, during the next two weeks they just start drying out.  After blooming and producing the tomato the same problem is occurring. As the blooms come out they will dry and fall off.  Needless to say the tomatoes plants have a short life span. They will totally stop producing around the middle of the summer.  I was told by the agriculture dept. that I was probably splashing water up on the plants too much when watering. This last year I only had a soaker hose on them.  The agent said to put straw down around the bottom of the plants, but to no avail.  Maybe there is a better method that you can help me with.  Are there other solutions that you might know?

 

AnswerFirst, get your soil tested.  Take a pint of soil to your local county extension office and see what the pH is and the levels of N, P and K.  I always want to start with the foundation of the plants, which is the soil.  If your soil is pitiful and rocky, you can enrich it with compost.  How is the drainage?  If they are sitting in waterlogged soil, they will die quickly.   We recommend that you rotate where you plant your tomatoes every year because many tomato diseases are soil borne, and attack the plants earlier each season, but problems beginning within two weeks of planting is pretty amazing.  I think we might have something else going on.  Mulching the plants to keep soil from splashing on the stems can slow down the disease spread, but again, it doesn't usually occur within two weeks of planting, nor does it cause the flowers to dry.  Most tomato diseases either start with the leaves dying from the bottom and it progresses up the stem, or we have a dramatic wilting and dying from one of the vascular wilts.  It sounds like your problem is more about fruit set than plants dying.  How much sunlight do the plants get? They need at least 6 hours a day.  Some varieties quit setting fruit when the temperatures get above 90 degrees during the day or stay above 75 degrees at night, but if the plants look good, they can kick back in and produce well into fall.  I think we need to investigate further.


(October 2010)

QuestionI have taken up some aucuba that I had growing on the north side of my house after they wilted and turned black.  I also have some oakleaf hydrangeas that developed reddish brown spots on them in the same area.  We cut them back a couple of years ago, raked up the old leaves and mulch, and they came back ok.  We didn't have any flowers last year, but this year we sprayed with a fungicide and we had lots of flowers.  Now late in the season, but later on the red spots are back. What do we do to get rid of whatever it is that is causing our problem?  Our tomatoes and peppers in small bed on the east side of the house are also affected.  Would you advise replacing the aucuba with healthy plants or going to a more disease resistant plant?

 

AnswerHow much sunlight were the aucuba getting--also the oakleaf hydrangeas?  We have had several situations where trees were removed or damaged and the plants were simply getting too much sun.  Aucuba turn black in direct sun.  This year, many oakleaf and regular hydrangeas have leaf spots.  It isn't all that rare late in the season, nor would I recommend starting a spray program this late.  If the problem starts early in the year then a fungicide might we warranted.  Water is still the most vital factor for success in a garden, and this year that was a challenge.  Lack of fertilization, heat and drought stress are probably your biggest problems with the vegetables.  I do not think the same thing is plaguing all your plants, but it has been a tough gardening season.


(August 2010)

QuestionBehind my house is a white oak tree.  It is approximately 40 to 50 years old, stands well above our wood deck.  It shades our deck and the pool below.  Overall it appears very healthy.  Every year, however, it starts losing leaves about July 1st.  I have a major cleanup of fallen leaves almost daily.  There is an almost identical oak, same age and variety about ten feet away with similar surroundings that loses no leaves at all until fall.   I feel the tree is infested with something.  At any rate, what can be done about the problem?

 

AnswerIf the tree does this every year, obviously it is not causing any major damage, since the tree looks healthy and fully leafs out each spring.  This year, there are numerous trees which are shedding large quantities of leaves due to lack of water.  You can really tell which trees are getting supplemental water and which aren't.  I would have had a hard sell with this theory last year because of all the rain.  Are there any symptoms of disease or insect attack on the leaves that are falling?  Keep in mind that trees have extensive root systems.  It is possible that this tree has limited roots due to the pool, house, etc.  You can take a sample of the leaves into your county extension office.  Examine the trunk, make sure there are no wounds or growths there, but if it is full and healthy every spring, I am not too concerned.


(July 2010)

QuestionHELP, my azaleas are dying!  We have well established azaleas, planted in 1995 and now they are dying.  It started last year with one or two and now several are going.  We live in mid-town, Little Rock, and have a sprinkler system.  Our house faces South and the azaleas are across the front and back.  The ones in the front started first and now the ones in the back are affected.  We trimmed them back this year and fertilized, however we have not removed old mulch.  The leaves turn yellow and sections of the plant dies first, then the whole plant. I have not seen any sign of insects. The watering system is set for 3 times a week at 10 minutes each time.  Am I watering too much?  Could there be disease from the old mulch?

 

AnswerTo properly identify what is going on, take one of the dying plants or at least a portion of the stems plus roots to your local county extension office so they can send it into our disease diagnostic lab.  There are several diseases it could be but we need to know for sure what is causing the problem before you start trying to control it.  I think watering for only 10 minutes three times a week is wetting the soil surface more than deeply wetting the soil. The goal in watering is to water deeply and infrequently. Soil type, amount of sunlight, and what you are growing are all factors in frequency and duration of watering


(April 2010)

QuestionI am having difficulty with my fruit trees.  Last year my peach tree produced lots of peaches, but they all dried up around the seed before they ripened. I also noticed that quite a few of the leaves and small branches dried up and died.   My apple tree made really good apples but the leaves dried up and died and I noticed yellow spots on the leaves that had several round dots in them. I assumed these to be some kind of insect eggs. The apples also had dark spots on them. I have already cut them back and am hoping that you can suggest some kind of spray, preferably something natural that I can use to solve these problems

 

AnswerFruit trees can be challenging for the home gardener, especially peaches which have numerous insect and disease issues.  Brown rot is the most destructive and can wipe out a crop seemingly overnight, especially when we have periods of rain, which were almost constant last year.  Pruning is something you will need to do annually, but a spray schedule is also necessary to produce quality fruit.  Purchase a home fruit spray which has both an insecticide and a fungicide mixed together.  There are organic products as well as non-organic. Start spraying when two thirds of the flower petals have fallen and then continue throughout the growing season, about every 10 days to three weeks depending on the weather.  Your apple tree sounds like it was infested with cedar apple rust.  This disease has two hosts--Eastern red cedars and apple trees.  By the time you see yellow spots rimmed in orange it is too late to spray to control it. The key is to do preventative sprays the first few weeks following bloom.  Orange gelatinous masses form on cedar trees releasing spores which then infest the apples.  Typically apple diseases are a bit easier to deal with since you can usually peel off the damage and still eat the fruit.  Spray schedules, cultural information and pruning guides are available on our Extension website at: http://www.arhomeandgarden.org/


(June 2010)

QuestionIs there any way to treat soil that would help fight tomato wilt?  The only information I can find in garden books is to "buy disease resistant plants" and throw away the ones affected.  I bought disease resistant plants and for the second year in a row, my tomato plants are healthy and have tomatoes on them one day and are wilted and dead the next.  It is very discouraging.  Can I plant anything in the fall (like clover) that might aid in cleansing the soil?

 

AnswerMany tomato diseases are soil-borne.  That means they persist in the soil for years and can attack your tomatoes quicker each season.  Planting disease resistant varieties helps, but only to a point.  For one thing, disease resistance doesn’t cover every disease out there.  Secondly, a new strain of the disease can build up especially if you plant over and over again in the same area.  Rotating tomatoes in the garden is ideal, but again, that alone may not do the trick.  The best idea is to sterilize your soil using soil solarization.  Till the soil as deep as you can, then saturate the soil, getting it really wet.  Once you have wet the soil, cover it with clear plastic, making firm contact between soil and plastic.  Leave it covered for six to eight weeks between July and September and you should start off with clean soil next year.  Cover crops such as clover and vetch can help to build up your soil, but do little to control diseases.  You can also take a plant sample in to your local extension agent when you have the disease, they can pinpoint exactly which disease issue you have.


(July 2005)

QuestionMy tomatoes have died because of what I think is a blight.  If this is in the soil of my garden, is there any way I could sterilize the soil so I could plant some late tomatoes and have some this fall?  Is there some fungicide I could use that would prevent it?

 

AnswerThere are numerous diseases that plague tomatoes.  Early blight, septoria leaf spot and late blight cause the “firing” up of the lower leaves.  It usually takes the plant by the end of the season, but you usually have had a good harvest by then.  Sprays weekly of a fungicide such as Maneb or Bravo can help to prevent it.  If your plants out and out died already, you may have one of the more serious vascular wilts.  These soil borne diseases can kill a plant within a few days time once they hit.  Soil sterilization can be done via the sun—called soil solarization.  Chemical products are no longer available to the home gardener.  To solarize your soil, till it thoroughly, wet it completely, then cover it with clear plastic, making firm contact between soil and plastic.  Leave it covered for six weeks.  Then you can replant.  You could have a good crop of fall tomatoes.  You could also get them growing in large containers.  Tomatoes can be container grown all season, just keep up with the watering.


(April 2010)

QuestionI have a Leyland Cypress that died last year, turning brown from the bottom up.    Now I notice two branches on a nearby Leyland that is beginning to turn brown.  Do I have bugs, fungi, parasites or chemical poisoning?  Or is the Leyland going the way of the red-tipped photenias?  Help.

 

AnswerI think the Leyland is going the way of the red tip photenias, but be aware that some red tips have not been affected by disease and some Leyland’s haven’t either, but disease is spreading on both plants.   There is a canker disease that affects Leyland cypress and there isn't much you can do once it hits. It is typically associated with some type of environmental stress.  All of our rains last season did not bode well for many of the needle type evergreens.  Here is a link to our fact sheet about the disease: http://www.uaex.edu/publications/PDF/FSA-7536.pdf  If you are replacing the plants, I would consider other options--Emerald or Green giant arborvitae; cryptomeria, or one of the hollies.

QuestionHave you had any other comments about the clematis vines just drooping over night and looking wilted?  One day they were beautiful, then the next they were looking sad and wilted.  They eventually began to grow back at the base, but I did not get any flowers after that.

 

AnswerIt sounds like your clematis is suffering from a disease called clematis wilt.  This disease tends to be an issue on large flowering early blooming varieties.  It is often worse in heavier soils or soils that do not drain well.  Unfortunately, the disease often attacks  the plant right as it is about to start blooming.  The disease enters the stem and clogs the vascular system, cutting off the supply of food and water to the top of the plant, causing it to wilt and die, seemingly overnight.  It only affects the plant at the soil line, leaving the crown and root system unaffected.  The plant eventually grows back from the roots, but if yours is a spring only bloomer, you have lost the flowers for that season.  All season bloomers, can rebound and still bloom.  Some gardeners are plagued with this disease annually until they raise the level of planting or move it to a new location. Others find that as the plant matures it seems to outgrow the problem.


(May 2010)

QuestionI live in northwest Arkansas and we have some small cedar trees at the edge of our lawn that has some orange (fungus?) looking things growing out of grey nuts? They look like a bunch of tentacles and are mushy. Are these harmful to the cedars?

 

AnswerWhat you are seeing with the bright orange tentacles is the fruiting body of cedar/apple rust on your cedar tree.  This disease has two hosts--Eastern Red Cedar and apples/crabapples.  The disease first starts on the cedar.  During periods of rain in the spring the galls quickly grow  orange, gelatinous tentacles that produce spores which then blow to the developing fruit and leaves on nearby apple and crabapples trees. Symptoms will appear on apple foliage as small round orange spots which then yellow.  Heavy infestations can cause the apple trees to shed foliage and deform the fruit lightly, but the disease is not deadly to either plant.  If you desire clean fruit, fruit sprays are needed in early spring.  They are only effective during the time the spores are active in early spring, and once you see symptoms, sprays are no longer effective.  If you don’t grow apple trees, you can ignore them or simply enjoy their odd appearance.  Here is a link to a fact sheet for more information: http://www.uaex.edu/publications/PDF/FSA-7538.pdf


(October 2007)

QuestionMy rose bush has black spots on the leaves and they turn yellow and fall  off. I have sprayed it with disease spray from the gardening center but it hasn’t helped.  Now it has almost no leaves and looks like it could die.  It usually blooms a lot in the spring and summer, but this year it only bloomed  in the spring and has been pitiful ever since.  I have had it for about 10 years and don’t want to lose it. What can I do?  Also there was an ant bed underneath it (small black ants and we sprayed them, could they have damaged the plant?

 

AnswerYour rose bush has the classic rose fungus disease called black spot.  This was a great season for diseases of all types, but if you have a susceptible variety, you typically have the disease every year in Arkansas.  Spraying after you see the disease is usually a futile attempt at control.  The key is to start your spray schedule in advance of the disease—soon after the plant kicks into growth in the spring.  Sprays every week to three weeks—depending on what product you use, will be necessary throughout the season. Black spot can weaken a rose bush, and if it occurs year after year, it can weaken it enough for it to die, but it should come back strong next spring with proper pruning, spraying and fertilization. I  don’t think the ant spray had any effect.


(June 2008)

QuestionI have planted some tomatoes in pots and all seem to be okay except one which the leaves are curling on and it does not seem to have as deep green color to the leaves.  What could be the problem?  Also what causes the blossom end to rot and what can be done for that?

 

AnswerLeaf roll (curling of the leaflets) is a physiological condition that occurs most commonly when plants are trained and pruned. Any type of stress can cause leaf roll. It usually does not affect fruiting or quality, and it is not a disease. Leaf roll is a common genetic trait in some varieties but it is typically not associated with a difference in leaf color. Monitor these plants, make sure you are watering enough, but don’t drown them either.  Use a water soluble fertilizer and see if that helps with the color.  Blossom end rot is a calcium deficiency that is usually brought about with huge fluctuations in moisture levels—we often see if when we go through a dry spell and then have a downpour of rain.  Even though your plants are in containers, mulch the soil to aid in keeping the moisture levels more constant.


 (June 2009)

QuestionMy tomatoes have developed on the bottom leaves a blight which is yellow.  The leaf slowly dies completely.  The disease works to the top of the plant and finally kills the plant.  I have had the same problem for the last couple of years.  This year I am using Ortho's Garden Disease Control, spraying twice a week. I wonder if I am using the right fungicide or I use something else?  I am also wondering if the blight is in the soil.

 

AnswerTomato plants suffer from a variety of soil borne diseases and several start with yellowing of leaves from the bottom and work their way up.  Two of the most common are septoria leaf spot and early blight.  Early blight appears as spots on leaves, stems and fruit. Leaf spots start as small, dark brown areas, sometimes with a yellow border. Leaf spots grow rapidly under favorable conditions, forming lighter brown bands with a dark center. Stem spots have even more noticeable rings than leaf spots and may cause plant death if the stem is girdled.  Another common disease that can be controlled is septoria leaf spot.  Spots on lower leaves usually show up as the first tomatoes start setting and may also form on stems and branches. Spots are round, and smaller than the early blight--about 1/8" across, with dark brown borders and light gray centers. Young spots may be surrounded by a yellow halo as well. The disease progresses up the plant, from the older to younger leaves, spread by splashing rain or overhead irrigation. Fruit infection is rare.  Both diseases can be controlled with a product containing chlorothalonil- (of which there are numerous trade names including Bravo, Daconil and Ortho’s Garden Disease control) or Maneb.  The key is not to wait to see the disease and start playing catch-up with fungicides. It is much easier to prevent than cure the disease.  Rotate your plants in the garden—don’t plant tomatoes back in the same soil for at least three years.  If you get the disease annually, start spraying when you plant and continue throughout the season.  Since you can still harvest tomatoes with both of these diseases, you could grow the plants with proper cultural conditions—water, sunlight, mulch and fertility and harvest what you can until the plants play out.  Then replant in a new location midsummer to have tomatoes for a fall harvest.


(October 2008)

QuestionI have a sugar maple, ‘Autumn Blaze’ about five years old in my front yard facing the south. It is at least 10 to 15 feet tall.  I recently noticed an area close to the bottom of the tree about 7 or 8 inches from the ground that is bleeding a black substance.  Is this usual or should I be concerned?

 

AnswerOne of two things can be happening.  Maples are notorious for “bleeding” sap from any wound.  If something wounded the tree such as a weed eater or lawn mower, this could simply be the case and is nothing to worry about.  The other scenario could be wetwood or slime flux, which is caused by a bacteria.   Gasses and liquid by-products of the bacteria cause the internal pressure of the sap to increase, forcing the liquid to ooze out any opening along the tree. It tends to have a sour or fermented smell to it and is quite attractive to insects. It can be dark in color or white and foamy.  While it doesn’t signal imminent death, it does tell you the tree is stressed.  Keep the tree as healthy as possible with regular watering.  Try to use your garden hose to remove the sap from the trunk of the tree as the fermented sap can be damaging to the trunk of your tree if left there.  This problem is usually more common during spring and summer.


(November 2008)

QuestionWe have quite a few hydrangea bushes in our garden. This fall we began to notice a few leaves developing dark spots that would enlarge on leaves and the leaves would finally die and fall off.  The leaves start with spots, then the leaves turn yellow, eventually brown, and then they fall off.  I don’t notice any insects but the plants do not look good at all. Is there something that we should be spraying with now to prevent this disease next season? Do you think it has killed our plants?

 

AnswerIt is not unusual to see spotting occurring on the leaves of deciduous plants late in the season, especially when we had as much rainfall as late in the year as we did this year.  There have also been reports that the hurricanes actually flew in some new insect and disease problems.  For now, no sprays should be needed, but do rake up all of the fallen leaves and get them out of the yard. You may actually want to replace the mulch under this plant as well.  This way, you can start the season out clean.  I would be surprised if a leaf spotting disease late in the season would be enough to kill the hydrangea.  Monitor the plants next spring and if you see leaf spots then, a fungicide may be called for, but not now.


(July 2008)

QuestionI have a white dogwood tree with yellow leaves falling from it.  Some of the leaves seem to have black spots and the tree looks a bit wilted. Do I need to be concerned?

 

AnswerI would take a sample of the diseased materials to your local county extension office. This season we have been seeing signs of the dogwood anthracnose (Discula destructive) that is more dangerous than the small spotted form of dogwood anthracnose (Elsinoe corni) which we have had for years. Symptoms of D.destructive begin in the lower crown and progress up the tree. Leaf lesions start as tan spots with purple rims, but can rapidly enlarge to large leaf blotches. If you do have this anthracnose, fungicide sprays would be warranted for control, along with pruning.  Here is a link to a newsletter from our plant disease clinic with more information on the disease complete with pictures: http://www.aragriculture.org/News/plant_clinic/2008/ten2008.pdf


(July 2007)

QuestionI have hostas and hellebores in a corner shade garden that are not doing well.  Every summer for the last 2-3 yr the hostas start to turn brown, and wilt, but do not die completely.  I was going to replace them last fall, but the root ball looked ok.  They came up this spring, but now they are wilting again.  The hellebores in the same area are finicky.  A number have died, and 2 plants look good.  Could this be nematodes?  Your publications talk about this with regards to crops, but not with garden ornamentals.  I am thinking of simply digging up much of the soil in this area and replacing it.

 

AnswerNematodes can be in any soil and can affect ornamentals just like crops.  Before you begin removing soil, why not take a soil sample with some of the hosta roots with it into your local county extension office.    For a fee you can get the soil tested for nematodes, and then a recommendation for control.  Here is a link to our website on how to take a sample for nematode testing.  http://www.aragriculture.org/nematodes/nematode_clinic.htm  I do think that potentially there is something wrong with the site, since various unrelated plants are struggling.  However, if the root system looked good on the hostas, then nematodes may not be the culprit.  Nematodes feed on the root system of the plants and cause stunted and/or deformed roots.  I would also suggest taking a regular soil sample in to your county extension office and see about the pH and nutrition levels.  I would also consider taking one of the hostas that is struggling in to be sent to the disease diagnostic lab.  This is a free service of our extension service.  When we have problems in the garden, you have to be a detective and cover as many bases as possible to find out what is causing the plants to suffer.


 

All links to external sites open in a new window. You may return to the University of Arkansas Division of Agriculture web site by closing this window when you are finished. We do not guarantee the accuracy of the information, or the accessibility for people with disabilities listed at any external site.

Links to commercial sites are provided for information and convenience only. Inclusion of sites does not imply University of Arkansas Division of Agriculture's approval of their product or service to the exclusion of others that may be similar, nor does it guarantee or warrant the standard of the products or service offered.

The mention of any commercial product in this web site does not imply its endorsement by the University of Arkansas Division of Agriculture over other products not named, nor does the omission imply that they are not satisfactory.