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Bob and Nicole's 

The Plant Clinic Page

copyright 2002 Bob and Nicole Stewart

I retired in 2003 after 30 years of working as a horticultural extension educator with the University of Maryland.  While I no longer "officially" work with the Extension Service I continue to  volunteer at the local County Extension office and with several Master Gardener groups throughout the state.  While I don't deal with as many plant and bug problems as in the past, I still give enough inquires to keep things interesting.  With this page I would like to share some of the more interesting and educational problems that show up in my volunteer activities. My home extension County was Prince George's County, Maryland, a large suburban county just east of Washington, D.C.  The county is located in USDA Zone 7 and has a population of approximately 700,000. 
  

Can I dig up and move my asiatic lilies in August?

        Bulbs, including the lovely asiatic hybrid lilies, should not be disturbed as long as the foliage remains green.  The green leaves and stems are manufacturing sugars for the plant which will eventually be moved into the bulb to build up the energy for next year's flowers.  Disturbing the plant when this sugar making process is underway reduces the food supply that will be needed by the bulb.  Wait until the foliage turns brown in early fall to dig and transplant the bulbs. 

What is this strange bug invading my home?

         A caller to the Extension office this week wanted help in identifying and controlling a strange insect that had invaded her home.  She described the insect as having a humped back and jumped so quickly when approached it seemed to literally disappear. When you get this type of call in late summer or early fall you know you are dealing with the camel cricket.  Camel crickets are similar in size to the more common field cricket but are light tan in color and have an unusual humpbacked appearance with heads bent downward between their front legs.  They have very long back legs which makes them very strong jumpers.  Camel Cricket
        Camel crickets prefer dark and damp situations.  Outdoors they live tall grass and weeds or areas under rock piles or hollows in trees.  They often migrate indoors and prefer damp basements or crawl spaces beneath houses.  As they forage for food they frequently find their ways into living areas.  Although they can sometimes feed on fabrics in the house they are mostly just a nuisance.  Unlike their field cricket relative they do not chirp or make other noises as they have no sound producing organs. 
        Keeping camel crickets out of the house involves reducing their numbers around the outside of the house.  Keeping tall grass, weeds, and leaves from around the exterior of the house will reduce their numbers near the house and reduce the chance they will get into the house.  Reducing moisture in crawl spaces or basements will reduce their numbers in those areas and lessen the chance they will move into the living areas.  Using weather-stripping around doors and windows and sealing any cracks or crevices leading to basements or crawl spaces will block them from getting into living areas.  Chemical sprays are usually not very effective in controlling camel crickets.  If a stray camel cricket or two makes its way into the living area a good vacuum cleaner is the best weapon, but you better be fast because they certainly are.  I assured the caller that her mysterious insect pest wasn't going to damage her house and wasn't going to bite or sting her or her family.  This was just another case of an uncomfortable interaction between us and the insect world. 
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What is this weed and how can I get it out of my lawn?

           A young man, who had just bought his first house, visited the Extension office seeking advice on improving his new house lawn.  His main concern was a particular grassy weed which was scattered throughout the lawn and even was showing up here and there in the asphalt driveway.  He had been told it was wire grass which in reality is really wild bermudagrass (Cynodon dactylon.)   Bermudagrass is a creeping warm season grass.   In the deep south improved varieties of bermudagrass are used as lawngrasses, but here in Maryland the wild type of bermuda is one of the worst possible weeds to have in your tall fescue or Kentucky bluegrass lawn.  bermudagrass weed
           Wild bermudagrass is extremely vigorous and extremely adaptive.  Once it has made its way into a lawn it will usually outgrow the desired grass species and form discrete patches from which it continues to reach out with its long surface stolons and underground rhizomes.  Although it's a perennial grass here in Maryland it goes dormant in the fall and dies back to the ground.  This leaves ugly brown and tan patches scattered throughout the lawn.  It's impossible to pull or dig up because invariably you will leave a small piece of the stolon or rhizome and it just grows back.
            Basically you have two choices when your lawn has been invaded with wild bermudagrass; (1) live with it, or (2) kill out everything and start over.  Neither choice is a good one.  If you go with choice #2 you spray your lawn with a non selective herbicide (weed killer), usually glyphosate (Roundup or another product carrying the same active ingredient), wait for everything to die, and then  reseed the lawn with a good lawngrass.  At this time we just don't have a chemical that will kill bermudagrass that's growing within a tall fescue or Kentucky bluegrass lawn.
            My visitor had his answer as to the identity of his weedy grass but he was unsure about what action he would take.  Even telling him I had bermuda in my lawn here at Cactus Hill didn't really cheer him up.  Establishing and maintaining a healthy and attractive lawn is not easy and for those of you who have achieved this I salute you. 
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Recommendations for a small, ornamental tree.

          One call during this week's volunteer session at the extension office was a request for a recommendation for a small, landscape, ornamental tree.  I usually don't like to give plant recommendations at the spur of the moment because you always tend to forget to mention several really nice plants.  Nevertheless, I do have a few favorites I recommended. 
           Winter King Hawthorn (Crataegus viridis 'Winter King')  is one of my favorite ornamental trees and not used nearly enough. The main ornamental feature of this tree is its fruit. The fruits are bright red, 1/4" in diameter,  and produced in great abundance.  They begin coloring in early fall and persist well into the winter.  Well fruited trees are glorious in December, providing a bright red spot in the landscape when everything else is going dull.  One slightly negative aspect is the thorns.  Like other hawthorns this one also has thorns on the branches but they are not as numerous nor as long as other hawthorn species.  The Winter King also has a lot less trouble with several diseases (rust and mildew) and insects (lacebug) than other hawthorns.  A really outstanding ornamental tree.      
            Flame Amur Maple (Acer ginnala 'Flame') is another small tree that is outstanding in fall, this time due to its foliage color.  The leaves turn a fiery red in fall and combine this with few if any pest problems and this is another tree that should be used more in our landscapes. 
            Bloodgood Japanese Maple (Acer palmatum 'Bloodgood') is used much more often than the previous two trees but is a very ornamental tree both for the wonderfully colored foliage (deep reddish purple all season) and the interesting branch structure.   As with other Japanese maples this plant needs a well drained but moisture retentive soil (the best analogy is soil like a damp sponge) and supplemental watering during hot, dry summer weather.
            Forest Pansy Redbud (Cercis canadensis 'Forest Pansy') is another commonly used plant but another plant with really outstanding colored foliage.  New leaves in spring are vivid red purple and and the color stays attractive through a good part of the growing season.   In partial shade it grows well but the foliage color takes on more green during the hot part of the summer.  However, for an impact tree in spring, this is a winner. 
            Donald Wyman Flowering Crabapple (Malus 'Donald Wyman') is a great ornamental tree with abundant white flowers in spring and glossy red fruit that persist into the winter.  It grows to a spreading tree about 20 feet in height and 25 in diameter.  Unlike many of the crabapples this one is almost never troubled by insects or diseases.  It's also tough, handling most soil conditions and hot, dry weather when necessary.   It may not be available at every garden center but it's a crabapple worth searching for. 
            Of course there are many other small, ornamental trees worth recommending but you gotta stop somewhere.
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Help!  My marigolds are turning brown and dying!

         Actually the brown and dead marigold was laying on the desk waiting for me when I arrived at the extension office to perform my three hours of volunteer plant clinic service.  The note attached to the sample simply said, "Please help me find out what's happening to my marigolds."  Here in Maryland the weather over the past month has been hot and very dry.  Factor that into a brown, dried up looking marigold and plant clinic experience suggest spider mites.  A quick inspection of the sample under the office's dissecting microscope confirmed the suspicion.  Spider mites thrivespider mites under hot, dry conditions and one of their favorite plants are marigolds.  Sometimes leafhoppers can compete with spider mites for destruction rights to marigolds but the microscope proved mites to be the primary culprit in this case.
          Unfortunately, once the marigolds are brown and dried up, there's not much you can do.  However, if you learn to recognize mite damage early, before the plants are totally brown and dried up, you can manage spider mites quite nicely with a thorough spray of  horticultural oil or insecticidal soap.  The key is recognizing the damage early.  Usually early damage appears as a lose of color in a small portion of the plant's foliage.  The leaves don't turn yellow but a speckling of white, almost as though someone spilled a little bleach on the plants.  The individual mites are very small and very difficult to see without magnification.  Sometimes you can knock the suspected foliage sample on a piece of clean white paper and if mites are present some will be dislodged onto the paper and you see what appears to be bits of dust walking around on the paper.  It's been my experience that spider mites are one of the most prevalent pest of the home landscape and garden, but they are often not identified due to their size.
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What's wrong with my apples?

        When I arrived at the Extension Office today for my three hour volunteer session there were a couple of apples waiting for me.  They were immature granny smith apples and they had a lot of small brown marks and scars on their surface.  apple maggot damage Attached to the apples was a sticky note with the question,"What's wrong with my apples?"  During the late 1970's through the mid 1980's our office would receive a lot of inquiries about problems with backyard grown fruits and vegetables.  Today, such questions are rather rare and I hadn't work with apples for several years.  Nevertheless the problems on the apples on the desk were relatively common ones, apple maggot and fly speck.  Apply maggot is one of the most common insect pest affecting apples.  A fly, somewhat similar in size to a house fly, inserts its eggs into the skin of the apple, causing a small, but noticeable scan.  The egg hatches under the apple skin and a small maggot begins eating its way through the apple flesh.  Once infested the apples usually fall off the tree before they are ripe.  The other problem, the tiny clusters of black spots, is a disease known as fly speck.  It's caused by a fungus and is often a problem when weather conditions are hot and humid.  These are just two of the many problems of growing good apples and the reason tree fruit such as apples are often sprayed periodically throughout the growing season. 
        One method of dealing with the apple maggot is the sticky, fake apple.  You can buy red sphere sticky traps that fool the apple maggot fly into thinking it's an apple.  When they land on it to lay their eggs they get stuck and die.  You are not going to get rid of all the apple maggot damage but you can reduce it to perhaps an acceptable level.  Another thing to do is pick up and trash all of the apples that drop early from the tree.  If these are infested with the apple maggot the maggots will leave the apples and enter the ground where they will complete their life cycle and mature into more flies that will attack more apples.   
         Fly speck disease doesn't make the fruit inedible and the unsightly spots can be simply peeled off.   All in all, growing good apples in the backyard is difficult where summer weather is hot and humid.  Of course many gardeners like a challenge and trying to grow good tree fruit will certainly supply that. 
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Help, something killed my pine tree?

        In my latest volunteer stint at the local Extension Service Office a caller reported that one of her five large white pines trees had turned completely brown and she was afraid whatever killed it was going to affect her remaining four trees.  She said the pines had been planted more than 30 years ago and we're more than 40 feet tall.  The one that died had looked ok up until about a month ago when she noticed some of the needles turning brown.  The browning rapidly progressed throughout the tree and now all the tree's needles were brown.  She said she went out to look at the tree more closely and found hundreds of tiny holes throughout the bark of the trunk.  When she asked about this at her local garden shop they told her the tree had been killed by borers.  She was now afraid the borers were going to attack and kill her remaining pines. 
       A rapidly dying pine and hundreds of tiny holes in the trunk point to an insect known as the pine bark beetle.  While it's true these beetles performed the coup de grace on the pine they were not really the ultimate cause of the pine's death.  Pine bark beetles are tiny insects.  The adults are small, cylindrical, hard-bodied beetles about the size of a grain of rice. Most dark red, brown, or black. The pine bark beetle attacks pines that are already in danger, usually due to stress caused by the environment.  In Maryland the two most common environmental culprits are heavy clay soil, which limits pine root development, and periods of hot, dry summer weather.  Actually, the caller's soil conditions were probably not that bad for her trees to have lived more than 30 years.  Now however, these large trees were finding it increasingly difficult to pull in enough water from their roots to satisfy the vast amounts of water being transpired from their mass of foliage.  As the trees become stress some chemical signal brings in the bark beetles and they finish the tree off in short order. 
       The key to preventing the other pines from being attacked is to keep them out of stress.  A program of watering when droughts occur and annual fertilization usually helps.  The caller's dead pine should be taken down and removed from the area.  The wood of the dead pine will produce a lot of young hungry bark beetles and this is not a good thing for the other trees nearby.  This is one of those instances where human nature works against us.  During droughts, when we think about our plants needing water, we tend to give priority to the tomatoes, flowers, lawn, and small shrubs, such as azaleas and roses.  We often completely overlook the backbones of our landscapes, the trees. Giving your trees a drink during periods of drought help stave off stress and those hungry insects that take advantage of that stress. 
       For more information about pine bark beetles check out this Clemson University web page. Return to Top of Page
http://hgic.clemson.edu/PDF/HGIC2010.pdf  

Was it wrong to have my lawn seeded in July? 

Actually the question the caller to the Extension office had was, "I just had my lawn seeded by a landscape company and I don't think they used a starter fertilizer;  is that going to cause a problem?"  I suggested that the lack of starter fertilizer was the least of his problems.  The real problem would be to keep new grass alive through the height of summer here in Maryland.  Heat and a sun high in the sky pull incredible amounts of moisture out of grass plants.  Add to that the fact that seedling grass has a very small root system and the results are usually dead grass.  If you keep the new lawn area watered daily and the weather is a bit cooler and more cloudy than usual a summer sown lawn might sneak by but the odds are against you.  Here in Maryland we recommended sowing grass seed in mid September.  Yes, it's still can be hot in September, but within a few weeks the weather will be cooling down and the new grass will have the time during the fall to develop the root system necessary to get it through the next summer.  So, yes it was wrong to have a lawn (at least here in the mid Atlantic area) seeded in summer.  Of course if you have a new home and  need grass to hold the soil in place, and you can't afford sod, you seed and take your chances.  But, when you have time options, wait until September.   Return to Top of Page

What's wrong with my willow oak tree?

      My latest volunteer session at the Extension office had a phone call from a young lady who was worried about an old oak tree in her yard.  She and her husband had recently bought a house that featured several large trees that provided wonderful summer shade.  One of these trees was a 70 foot willow oak (Quercus phellos) which over the winter had developed several large dead limbs.  All the limbs were on the same side of the trees and a strip of bark had also fallen off of that side of the tree.  In the area where the bark had fallen off there were several clumps of some type of fungus growing on the tree.  Her worry was that her tree had been infected by some type of disease and this disease was going to kill their tree. lightning damage to pine tree
       Fortunately, there are very few infectious diseases that affect oak trees and are serious enough to kill off large branches and sections of the main trunk.  The young lady indicated that the damaged area of the trunk was in a vertical pattern starting about five feet from the ground and extending up past where the branches had died.  She said other than the dead branches and dead trunk bark the rest of the tree looked fine.  To me this all sounded like an injury not a disease, and the injury that often causes trunk damage in a vertical pattern is a lightning strike.  When lightning strikes a tree it heats and kills the tissue directly under the bark, usually in a vertical pattern running from the top of the tree to the bottom.  All of the branches that originate from this vertical strip often die or suffer severe dieback.  The young lady's tree was probably struck the previous summer and the branches died over the winter.  
[the pine tree pictured at the right shows a characteristic vertical dead strip due to a lightning strike]

       Although the unfortunate willow oak had lost a few branches and sustained some trunk damage the prognosis was generally good.  The dead branches would have to be taken out and the tree given a little TLC (this primarily means keeping it watered during dry summer weather) for the next four or five years.  Once the damaged area of the bark had healed along its edges the tree would continue along fine.  Lightning strikes often kill trees outright but in this case the house shading willow oak was going to be a survivor.   
        My final suggested to the caller was to work with a local tree company in having her tree pruned and inspected annually over the next few years.  For those of you in Maryland Nicole has put together some information on selecting a local tree company  and you can review that info by clicking HERE.  If you live in another state check with your local Cooperative Extension Office for help in selecting a tree company in your area.   Return to Top of Page

Can you identify this strange caterpillar I found on my tomatoes.

        tomato hornworm with parasitesThis is another one of those questions you get several times each summer. Usually by accident a gardener finds a tomato hornworm caterpillars on their tomato plants.  Anyone who has grown tomatoes soon knows what this rather large green caterpillar is, but then one year the caterpillar looks different; it's covered with white egg like things.  The first thought is that the caterpillar has laid hundreds of eggs and soon hornworms will take over the tomato patch.  Actually the white egg like things are the cocoons of a small, parasitic, braconid wasp.  The female wasp inserts her eggs into the caterpillar's body and the baby wasp larvae develop inside.  When the wasp larvae reach their final immature stage they push through the caterpillar skin and build a small cocoon.  Soon the new adult wasps will tear their way out of the cocoons and fly off to mate and infest more tomato hornworm caterpillars.  Once you find the cocoons on a hornworm it's best to leave the caterpillar alone and allow a new population of parasitic wasps to enter the fight to save your tomatoes.  Return to Top of Page

Help, a groundhog is eating my garden.

      Which gardening question do I dislike the most?  Could it be those dealing with problem animals?  You bet it could.  And why?  Because there are no easy answers.  While rampaging deer are the worst animal pests, the groundhog or whistle pig is a very close second.  A couple of adult groundhogs can go through a nice vegetable garden like a choppermatic and leave very little for the poor gardener.  The caller's question hit close to home because Nicole and I have had our own battles with this fat, furry, eating machine.  When dealing with animal problems there are four basic approaches:  (1)  exclusion, (2) eradication, (3) repellency, and (4) tolerance.  Yes, I know (4) is a cop-out but sometimes it's all you have left.   Usually I suggest starting with repellency because this is the easiest and most inexpensive method  for most people.  Sometimes various chemical repellents work easily and quickly.  Sometimes they don't.  It may depend on the hunger of the animal or just the personality of the animal.  Some repellents involve smell, some involve taste, and some involve scary things (worthless CD's on string) dancing in the wind.  Did you know you can buy coyote urine as a repellent?  Who collects that? 
       Eradication means trapping or killing.  In some parts of the country problem animals become part of a target practice exercise.  Where fire arms are illegal or not practical, poison baits are another eradication option.  Humane trapping is preferred by many but comes with a big problem; where do you release your captive?  Legally you can't release a trapped animal on someone's property, including government property, without the owner's permission. 
       Exclusion usually means a fence of some kind.  The best type of fence to deal with a problem animal is electric.  This usually involves a fence with an electrically charged single or double wire.   Such fences are relatively inexpensive and easy to set up.  Still, exclusion is generally more of a hassle than repellency which is why I suggest trying a repellent first.   Return to Top of Page

What are the trees with the large purple flowers?

      Last week (May 4th) a caller asked about the unusual flowering tree she was seeing along the roadsides here in Maryland.  The trees were about 20 to 30 feet tall with masses of large light purple flowers.  She had never seen such trees before.  What were they and where did they come from?  I'm glad she asked because this is certainly an interesting tree. The Chinese empress tree (Paulownia tomentosa) arrived first in Europe about 1830.  It was named for Princess Anna Pavlovna, wife of Prince Willem of the Netherlands, and daughter of Russian Tsar Paul I, and granddaughter of Catherine the Great.  Sometime around 1845 it was introduced to the United States.  Initially it was widely planted in the South but soon became naturalized from southern New York to Florida west to Texas.  The Paulownia is extremely fast growing, up to four feet per year, and very floriferous, producing a tremendous quantities of seed.  One mature tree is capable of producing twenty million seeds.
     In Japan the Paulownia is associated with the custom of a father's planting the tree upon the birth of a daughter and harvesting it to make a bridal chest when she reached marriageable age.  The wood is fire resistant and chest made of it protected the kimonos stored within.  In the 1970's a disease had killed many of the Paulownias in Japan and they began importing trees from the United States.  For the first few years Paulownia trees brought high prices and there were cases of trees being cut down and stolen from public and private properties during the night.  While the prices for wild trees has dropped dramatically, cultivated trees with straight trunks can still be profitable. 
     A mature Paulownia in flower is quite a spectacle.  The pale violet flowers are large, two inches in length, and vanilla-scented.  The flowers are borne on foot long, upright panicles and cover the tree in early to mid May.  When in full flowers the trees standout as they grow wild along roadsides and in abandon fields. 
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I have orange things with tentacles on my juniper?

      As we moved into the latter part of April I was expecting one or more of the "orange octopus" phone calls. Today a lady called to report the first one of the season.  The "orange octopus" is a spore stage of the fungal disease Cedar Apple Rust.   Most rust diseases are unique in that they require two different host plants to complete their life cycle.  Two the two host plants for cedar apple rust are junipers (red cedar is a type of juniper) and apple, or crabapple.  The disease is damaging to apple but not to the juniper.  On apple trees the disease causes yellow orange spots on the leaves and loss of the leaves during the summer.  This premature defoliation cuts back the food production of the tree and  reduces fruit production the following year.  On juniper the only indication of an infection is the production of spore forming galls.  At first these galls are green, marble sized growths on the branches but in mid spring the begin to swell and then produce clusters of long orange, jelly like tentacles.  The galls do no harm to the juniper but they scare the homeowner plenty.   The end result for this caller was that she was relieved to hear their junipers were not going to be damage. She had already made her husband go out and remove on the orange octopi.  Return to Top of Page

How can I get rid of the webworms in my trees?

     Here in the mid Atlantic region we are having a banner year for the insect pest known as the Eastern tent caterpillar.  Eggs of this caterpillar hatch on the trees (they prefer flowering cherries and crabapples in the landscape) in early April and the caterpillars immediately begin building webby tents in the branch crotches.  The caterpillars stay in the tents at night and on rainy days, but on other days they crawl out and feed on the trees leaves.  Sometime in late April or early May the caterpillars leave the trees in large numbers and seek sheltered locations to build a cocoon and enter their pupal stage.  In June and July the adult moths leave the cocoons and take to the wing to mate.  After mating the females go back to their host trees, lay eggs on the smaller branches, thus completing the life cycle. 
     The Eastern tent caterpillars seldom kill their host trees, but the tents are ugly and once the caterpillars leave the trees and swarm throughout the landscape and around the house, they become an unwelcomed nuisance.  The best control method is to spray infested trees with the material B.t., which stands for Bacillus thuringiensis.  This is a naturally occurring bacteria that is commercially produced and sold like a regular insecticide.  Nearly all garden centers carry a B.t. containing product.  It must be sprayed on the leaves of the tree, not on the tents.  B.t. is basically non toxic to humans and other animals.   You should try to spray as soon as the tents are noticed.  Once the caterpillars get bigger than 3/4 of an inch in length.
      For those who are not the squeamish type you can get rid of the caterpillars and their tents by simply pulling them out of the trees.  Wait until dusk when all the caterpillars have returned to the tents,  put on a pair of heavy gloves, have a trash bag  ready and  grab the tents pull them out of the branches and into the trash bag.  Of course if the tents are high up in the tree it's best to stick to the spraying with B.t. option.  Climbing up into large trees at dusk is not recommended. 
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Why are lady bugs invading my house?

       This is a question that has come up numerous times during the past four of five years here at the Extension Service office.  Lady bugs, or beetles, are suppose to be out in the yard devouring plant pest insects, not flying to and fro from one window to another in the house.  The lady beetle in questions is the Asian Lady Beetle.  This lady beetle is relatively new to our country. It's native to Asia (e.g., China, Russia, Korea, Japan), where it dwells in trees and fields, doing what it is suppose to do -- eating aphids and scale insects.  The problem begins in the autumn when the air begins to chill and these lady beetles look for a protected place to spend the winter.  Unfortunately, one of their favorite wintering spots is cracks and crevices of someone's house.  They congregate around window and door frames, behind  siding, and within attics, and wall voids. Older homes and homes in poor repair with many cracks and openings are most vulnerable to infestation.  When temperatures begin to warm in the late winter and early spring the beetles become active and many, instead of heading outside, get mixed up and find their way into the house. 

Asian Lady Beetles don't bite or sting or eat the house, but when they are there in the hundreds or more, their nuisance value is high.  Once the beetles are indoors, the easiest way to remove them is with a vacuum cleaner. A regular visit to the windows, especially those on the sunny side of the house, with the vacuum can greatly reduce their numbers.  Sealing as many cracks and crevices outside the house will help keep them out, but this is difficult on older homes.  Perhaps the best course of action is a quiet resignation to the forces of nature.  It could be worse, they could be wasps! 
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What are these strange growths on my forsythia?

     One of today's callers had gone outside to closely admire their flowering forsythia only to discover some of thephomopsis galls branches were covered with strange, tumor like growths.  She wanted to know what these were, and whether they posed a threat to her forsythia.  Her forsythia's problem is known as phomopsis galls and they occur quite frequently on forsythia.  Actually, there some argument in the horticulture world as to the actual cause of these strange growths on the stems of forsythia.  While the majority of opinion supports the cause as the fungus phomopsis there is little research data to prove exactly what causes the galls.  As to my caller's second question, the galls are not a great threat to the forsythia but whenever a branch develops numerous galls it seems to lose vigor and flowers poorly.  The best  course of action is to prune out the infected branch whenever a gall is found.  Since forsythia grows fast such pruning works well. 
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How do I get rid of unwanted bamboo?

  A caller to the Extension office this week had a question that frequently comes up;  "how do I get rid of bamboo?"  In this case the caller had recently moved into a new house and the backyard featured a small area of  tall, evergreen bamboo.  She had heard of horror stories where a planting of bamboo had taken over the yard and she wanted to tackle this problem while the bamboo was still in a small area.  This was a wise decision on her part because large expanses of  bamboo can be extremely difficult to eradicate.  Of course even getting rid of  a small bamboo planting will take time.  There are two options for practical bamboo control. 
      First, you can repeatedly cut the bamboo off at the ground to prevent the formation of leaves.  This eliminates or greatly reduces the ability of the bamboo to manufacture food and once all the food stored in the roots and rhizomes are exhausted the bamboo dies.  Unfortunately, the starvation method can take two to five years to kill out the bamboo, and the larger the original stand the longer this method takes. 
      The second method involves the use of a herbicide (weed killer).  The most commonly  used chemical is glyphosate,  sold in a number of products, the most common of which is Roundup.  In this method the bamboo is allowed to produce a set of leaves and then the glyphosate is applied to the leaves.  The glyphosate is absorbed through the leaves and moves through the plant into the roots.  The application is best made in late summer or early fall. While this method usually works faster than the starvation method it can still take two growing seasons. 
      The moral of the story is, don't plant bamboo unless you really, really, want it. 

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What's the problem with sowing grass seed in the Spring?

      A visitor to the Extension office has a lawn that is not up to par.  He indicated he had about 85% grass cover and the remaining debris or bare ground.  He thought the best thing to do was over seed the area, but he was concerned because he had heard that here in the mid Atlantic area September was the best time to seed.  He wanted to know what was wrong with sowing grass seed in the spring. 
      September is the best time of the year to sow grass seed.  There are three reasons for this.  First, soil temperatures are very warm in September and the grass seed will germinate readily if provided with adequate moisture.  Second, as the young seedling grass develops the weather will be getting progressively cooler and this is perfect for cool season grasses such as Kentucky bluegrass and tall fescue.  Third, grasses planted in September will have nine months in which to develop their root systems before they must face their most difficult season of the year -- summer.  Grass seed planted in the Spring have things a bit backwards.  The soil is still cool or cold in spring and this slows germination.  As the young grass is starting to grow the weather is getting progressively warmer, and within three months of  sprouting the grass will have to face its first summer.  There is a fourth problem with Spring planting, it puts a road block in a crabgrass control program.  Crabgrass preventing chemicals should be applied in early spring but these chemicals will interfere with newly planted grass seed sprouting. 
      Despite all of the above I recommended he overused his lawn this spring.  Why not improve his lawn this spring as much as possible.  If some, or much, of the young grass doesn't survive the summer, he can overused again in September.  The only loss is the cost of the seed and his labor.  As for the crabgrass control, which he did want to use, there is only product on the market called Tupersan.  It contains a crabgrass preventing chemical that is compatible with newly seeded lawns.  It costs a bit more than the traditional crabgrass preventing chemicals but it allows spring overseeding. 
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Is it too late (in mid February) to plant my tulip bulbs?Tulips

 
       This is a perennial question to the Extension office in February.  The caller had purchased a bag of tulip bulbs in the fall and for a variety of reasons never got around to planting them.  Not wanting to waste money, the desire is to plant them now.  A tulip bulb is a flower packed by nature into a small oval vegetative package.  However, nature has devised a system to prevent the flower from emerging too early.  A flower appearing in late fall or during the winter has a slim chance of being pollinated because there aren't any insects active.  Nature has designed the tulip bulb to wait until spring to flower when pollinators are available.  Nature has accomplished this by flower inhibiting chemicals in the bulb that are deactivated by  a certain period of cold weather.  For most tulips there needs to be approximately 8 to 10 weeks of cold temperatures, usually below 50 degrees, followed by a gradual soil warm up to allow the bulb to produce its flower.  Planting the bulbs in fall satisfies this cold requirement.  The question is.......if we plant tulip bulbs in mid February, will there be a sufficient number of cold days to allow the necessary chilling requirement?  Maybe.  It all depends on whether or not late March and early April will be cold enough, and who can predict the weather two months in advance....not me.        
     My recommendations are to go ahead and plant the bulbs if the yard soils allows it.  Often a mid February planting provides enough cold to get a batch of  late April or May tulip flowers.  Once we pass through the month of February it is unlikely there will be enough cold time to satisfy the chilling requirement.  Moral of the story -- if you buy spring flowering bulbs in the fall, plant them in the fall.
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When do I start my seeds indoors? 

     A caller to Extension office wants to grow their own petunias and tomatoes from seed this year -- a a goal close to my heart as I'm a life long "from seed" grower.  The basic rule is to decide when you anticipate planting the seedlings you grow out into their permanent garden positions, then count back the number of weeks it will take to grow seedlings to transplantable size.  Let's start with petunias.  These are annuals that can take a bit of cool weather and here in Maryland could be planted out in mid April.  Petunias are small seeded and the seedlings grow rather slowly so it will take approximately 8 weeks from seed sowing to transplantable size.  Using these two bits of info we can arrive at an approximate date of mid February to start petunia seeds.  For tomatoes we don't really want to plant them out until the weather is warm and settled (unless your goal is trying to get that first tomato by July 4th.)  Here in Southern Maryland I don't plan to plant my main tomato crop transplants into the garden until May 15th.  Tomatoes grow a bit faster than petunias and six weeks is enought time to grow a transplantable transplant, so seeds should be started at the end of March.  It's hard to resist starting some tomato seeds earlier than this but it's also hard to have that six inch tall transplant longing for the garden while early April experiences that unheard of artic blast with temperatures in the 30's.  Good advice here:  don't start seeds too early. 
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What's wrong with my indoor pine tree?

     December and January are very slow months in the Extension Office.  In fact during the last two days I have volunteered at the office I have only had one office visitor.  She brought me a small sample of a dried up looking evergreen in a plastic sandwich bag.  She told me it was her potted pine tree which she received as a gift two years ago.  She had been away from home for ten days and when she returned the pine looked fine, but over the following week it had progressively turned light brown in color and now many of the needles had begun to fall off.   The sample indicated this wasn't a Pinus species.  At first it looked more like a red cedar (Juniperus virginiana) but landscape plants  from cold winter areas don't survive long when grown in pots and kept in the house all year.  Then it all came together, this was a pine, but not from the genus Pinus -- this was a Norfolk Island Pine.  The Norfolk Island Pine (Araucaria hetrophylla) is a tropical evergreen from the South Pacific.  Unless you live in a frost free area this pine is a pot plant.  Alright we have established what it is, now, what's wrong with my visitors plant? 
     Unfortunately, my visitor didn't bring the plant to the office, so I had to make a few assumptions.  Most potted, tropical plants are in a potting mix with a lot of sphagnum peat.  Sphagnum peat is a great potting mix ingredient because it holds water and air at the same time.  However, sphagnum peat is not so great if it's allowed to dry out.  When dry it is hydrophobic.  That's a fancy word meaning that when dry it's very difficult to get wet again.  As the sphagnum peat dried in the pot (remember she was away for 10 days and the plant hadn't been watered) it shrank and pulled away from the sides of the pot.  When she tried to water it, after her return, the water simply ran down the openings around the side of the pot and out the bottom.  The central core of potting soil (with all the hydrophobic peat) remained dry.  The plant simply was drying out from lack of water in the potting soil.  The solution is to place the plant in a tub of warm to hot water for several hours to allow water to slowly soak back into the sphagnum peat.  Hopefully the plant hadn't dried out to the point of no return. 
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What can I do about moles?mole

     Based on the number of phone calls I receive at the Extension office, moles drive people nuts.  My first call today was about moles wreaking havoc on a home lawn.  It was compounded by the pet dog, which was digging the yard to shreds in a fruitless effort to catch a mole.  Some years ago I wrote an article for our Extension newsletter on the eternal battle between moles and men  --  and women.  If moles are, or have been, on your mind, give the article a read.   When mole hills become mountains.
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What is this thing and what's it doing to my Leyland cypress?

bagworm

This is a bagworm and it's a serious insect pest of many evergreens.  It looks like it's part of the plant.  That's results from the way the insect, actually a type of caterpillar, builds the bag.  First it spins a small bag made of silk webbing.  It sticks pieces of the plant on the outside of the bag which adds a remarkable bit of camouflage.  The small caterpillar lives inside the bag, only sticking its head out to munch on the plant tissue. While a single bagworm insect can't do too much harm, there are often hundreds, and hundreds can eat enough to cause considerable browning of the plant.   

The active bagworm feeding cycle runs from egg hatch in June until the females lay their eggs in late summer.  From late summer until the following June only the eggs remain in the bags, which are still hanging from the plant.  It is essential to pick off as many (all) of the bags before the eggs have a chance to hatch the following June.  While only half of the bags will contain eggs (those bags that housed the females) there will be approximately four or five hundred eggs in each bag. 

For more information on bagworms and control suggestions take a look at this University of Nebraska site.  http://ianrpubs.unl.edu/insects/g4.htm

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