Carpenter bees- Destructive Home Invader

May 17th, 2012

The carpenter bee looks like a bumble bee but has a glossy black abdomen

Carpenter Bees  Xylocopa and Ceratina species (Hymenoptera: Xylocopidae)  may look like the humble bumble bee but their burrowing habit to protect young offspring can create havoc with a wood structure like your home.  According to MSU Extension Entomologist Howard Russell “The most common carpenter bee in Michigan resembles many of the closely related, large yellow and black bumblebees we have here.”  He says that the top of the abdomen of a carpenter bee is bare and shiny whereas the abdomen of bumblebees is covered with black and yellow hairs. 

Also, effective pollinators, other species of carpenter bees may be black, green or somewhat purplish with various markings of whitish, yellowish, or reddish hairs, and may be considerably smaller.  Even though their native nest of choice would be an old tree, carpenter bees can be serious wood destroying insects if they choose your home to build their nest galleries.  Russell says that the tunnel created by the boring bee is so perfectly round it appears to have been drilled by a tool.   Carpenter bees seem to prefer softwoods like cedar, redwood and clear pines used in window trim, screens, soffits and fascia boards, and decks. 

Carpenter bee tunnels in end grain of cedar trim

 

These bees do not eat wood like a termite does but they use their galleries to raise a brood of youngsters.  Each larva is provisioned with a ball of pollen and then sealed into a single cell until it completes its development the following spring.  Most species of carpenter bees in Michigan have a single generation per year.  

Carpenter bees can be controlled by applying a registered insecticide to the gallery opening.  If only one or two gallery openings are involved then an aerosol Bee and Wasp spray should be enough to kill off the bees.   If large areas are affected then a persistent insecticide like cyfluthrin (sold as Bayer Advanced Garden Insect Control for homeowners or Tempo for commercial applicators) or bifentrhin (sold as Ortho Home Defense Max) can be used to treat the entire area.  Painting or otherwise sealing the wood is reported to discourage the bees from chewing their holes.  

Be sure to read and follow all the instructions and safety precautions found on the pesticide label before using any pesticide. 

Carpenter bee larvae

Photo: Damage: Sandy Heng
Photo: Bee: Rebecca Finneran

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Making the Most of your Soil Test-pH

May 9th, 2012

A garden soil’s pH is a measure of its acidity or alkalinity. This is important to know when growing plants because pH influences the chemical and biological reactions that occur in the soil, including the availability and uptake of essential plant nutrients.  Plants have different nutrient needs. Some species such as rhododendron or blueberry,  perform best with a more acidic pH level;  others, such as lawn grasses, prefer a more neutral or alkaline pH.   

Soil pH is measured on a 14-pointscale that runs from most acidic (1) to most alkaline or basic (14). A pH of 7 describes a “neutral” pH meaning that alkalinity and acidity are equally balanced.  Michigan soils can range from 4.5 to 8.5, depending on the soil’s parent material and the environmental or cultural influences of previous crops grown.  For instance, if a home owner applies lime to a lawn every year, the soil pH is likely to be above 7,  even if the parent soil is naturally more acidic (less than 7 on the pH scale).  

Changing pH
It is important to remember that not all soils are created equal.  Depending on a soil’s parent material, organic matter, temperature and moisture, changing soil pH may take time. Soils have the ability to buffer or resist changes.  Also, changing pH by one point is not as difficult as changing it two points.

 Products containing limestone or sulfur can help raise or lower soil pH, respectively.  Be aware that too much of any product can work against an effort to improve a plant’s growing environment.  To quickly alter the soil pH, work the amendment into the soil to the depth of around six inches.   Where this is not possible (as in established lawns, orchards, or landscapes) soil surface applications are the necessary.  In this case, the resulting change will take one or more seasons.   

While soil pH increase can occur rather quickly using certain lime products, it may take several months for sulfur to provide the same acidifying result. Soil microorganisms play an important role in converting sulfur to acid and this reaction also depends on temperature and moisture.  

Raising Soil pH
When soil pH is too low (acidic), lime can be used to neutralize or raise the pH level.   Products like dolomitic or calcitic limestone, hydrated lime and even wood ash have different chemical properties and can be used to accomplish different things in the garden soil. Limestone products are also useful as a source of calcium when this nutrient is too low (which can occur in sandy soils).  Apply products as recommended by your soil test report and incorporate them to a depth of six inches when possible. 

Lowering Soil pH
If the soil pH is too high (alkaline), it can be adjusted by applying sulfur to the soil. Products commonly available include elemental or ground sulfur, iron sulfate and aluminum sulfate. When needed, most plants will benefit from using any of these products.  However, a few plants are a little more specific in their requirements. To lower the pH for rhododendron, use ground/elemental sulfur or iron sulfatesince aluminum can be toxic to rhododendron. When blue hydrangea flower color is desired, lowering the pH with aluminum sulfate is best since the aluminum helps to enhance blue color.  Apply products as recommended by your soil test report. If a sulfur product comes into contact with plant leaves, it should be promptly rinsed off. 

Other things that Affect Nutrient Availability
Some essential plant nutrients (such as nitrogen) are less available in cold or water-logged soils.  Plants exhibiting nutrient deficient symptoms may actually be unable to get the nutrients that are already in the soil. Lawns that are slow to green up during a prolonged cold spring do not need additional of fertilizer applied to correct a sometimes “off-green” appearance.  Only time and temperature can correct this situation. 

To obtain your own soil test kit log on to www.bookstore.msue.msu.edu and use product code E3154 or contact your local MSU Extension office at 1-888-678-3464. 

For more information on a wide variety of garden topics, you can log onto www.migarden.msu.edu or
contact MSU’s toll-free garden hotline at 1-888-678-3464 with any of your questions.

 

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Fertilizing Established Perennials—Feed ‘em and Weep.

May 9th, 2012

Perennials generally do not have a high fertilizer requirement and in fact, some will react negatively to routine fertilization.  An over-fertilized perennial will reward the gardener with excess growth that flops over and becomes leggy.  Over fertilization can also affect bloom performance, producing ample foliage at the expense of blooms.  Many perennial experts recommend no fertilization when plants are in a healthy garden soil.  However, if your soil is composed primarily of sand with little organic component, your plants will probably benefit from routine, light fertilization.  

Understanding the natural growing range of your perennials will enable you to create a growing environment similar to the plant’s native habitat.  It is helpful to keep a watchful eye and journal of plant “behavior” in hopes to correct situations such as leggy growth and poor performance in subsequent years.  

Perennials may benefit from a single fertilizer application just before or at the time that new spring growth is pushing up.  The most common recommendation is no more than one pound of nitrogen per 1000 sq. ft. if no compost is used. For comparison, this is about ¼ of what you would apply to your lawn during the course of a growing season.  

Broadcasting a slow release fertilizer is the best choice to meet season-long plant nutrient requirements, but you can also use a balanced fertilizer such as 20-5-10.  If your soil test indicates that you do not need phosphorous, choose a product such as 20-0-10.  

Slow release products are usually effective for either a 3-4 month window or a 5-6 month window of action.  If you are topdressing or using supplemental feed at any time during the season, the 3-4 month product should work well.  If you only intend on fertilizing once during the season, then the 5-6 month product should be used.  

You can also use the side dress method, applying several tablespoons of fertilizer (according to the manufacturer’s guidelines) in the general root zone of each plant.  Make sure not to allow fertilizer granules to cluster in the crown of the plants as it may cause burning.  In the early spring, cool soils can have an affect on uptake of certain nutrients, at times making the foliage appear light green or yellow (nutrient deficient.)  If this appearance does not diminish as the season progresses, spot treating with liquid feed will bring about a quick green up.  

Compost Insurance
If you routinely apply a one-inch layer of compost or leaf mold to your garden each year, you can often eliminate fertilizing all together.  This is where having an understanding of each plant’s needs and observing leaf color and growth habit will help you avoid excess fertility.  

Certain perennials tend to be heavy feeders, by nature.  Daylilies (Hemerocallis), peony, Chrysanthemum and tall phlox will benefit not only from a spring feeding but also with a secondary application during the summer.  In this case, side dressing with a product that has immediate availability (not slow-release) or using a liquid product is the best choice. Perennials that you cut back to the ground during the season, allowing new foliage to flush out and bloom a second time such as Delphinium, daisy and Pulmonaira will also benefit from spot treating with a liquid product.   

Do not fertilizer perennials in late summer or early fall.  This may cause the plants to flush out additional growth that will not harden off in time for an early winter freeze.  

For more information on a wide variety of garden topics, fact sheets and videos you can log onto www.migarden.msu.edu or contact
MSU Extension’s TOLL FREE Garden Hotline at   1-888-678-3464  with any of your questions. Rebecca Finneran is a Michigan State University Extension Horticulture Educator, garden writer and lecturer.  

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Fertilizing Newly Planted Perennials

May 9th, 2012

Proper preparation of planting beds using well rotted compost, commercial organic matter or leaf mold will ensure good success when establishing a new planting.  Preparing soil by loosening compaction and working three to four inches of organic matter into the top twelve inches of soil will provide your plants lasting nutrients for several seasons.  If your soil test indicates you need added nutrient, you can incorporate it at the time you prepare the bed.  

Most perennial growing recommendations note that between one to four pounds of nitrogen can come from a one inch layer of organic matter like compost so don’t over-do the supplemental fertilizer application.  In all cases, slow release products are better for your plants and the environment.  Apply a slow-release fertilizer according to the manufacturer’s recommendations as a “side dressing” at planting time.  

Whether renovating whole beds or only a few plants at a time, you can refresh the planting area by amending with compost to the depth the new plant will be planted.  If plants are to be removed and divided, simply lift the entire plant out and set aside while spading in 3-4 inches of compost over the area that is to be renovated.  Replant divided sections or a new plant into the area keeping in mind that the soil will “settle” as the organic matter decomposes.

 A Tight Squeeze
New plants that have been purchased are sometimes container-bound with tightly growing roots.   Media around the plants can become extremely dry in the center of the root mass and watering over the top sometimes will not remedy the situation.  A healthy soak in a bucket or wheelbarrow will allow the dried out area to re-moisten and allow you to untangle the roots so they will establish more quickly in your garden bed.  Do not be concerned about breaking a few roots.  

Perennial growers commonly agree that when it comes to fertilizing perennials “Less is more” is the best rule of thumb.  As you continue to grow perennials, and observe their response from year to year from your treatments you can adapt to each plant’s specific needs.  

For more information on a wide variety of garden topics, you can log onto www.migarden.msu.edu or contact
MSU Extension’s TOLL FREE Garden Hotline at     1-888-678-3464    with any of your questions. Rebecca Finneran is a Michigan State University Extension Horticulture Educator, garden writer and lecturer.  Her BLOG can be found at www.stuckongardening.com

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