Information you can really dig into

This newsletter offers timely information for your outdoor living spaces.  Addressing the most common questions ranging from container gardening, tree pruning, wildlife management, to fire ant control, insect identification and lawn establishment.

Click here for a printable version of this newsletter.

Shawn Banks
Extension Agent
Agriculture—Consumer Horticulture

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THE FEATURE ARTICLE

The Cover Crops

By Shawn Banks

Now that the summer vegetable garden is on its way out, I thought it would be a good idea to do an article on cover crops.  I had no idea there was so much information on the use of cover crops.

I expected to find information about the nitrogen fixing benefits of legumes as a cover crop.  To receive the nitrogen benefits, the cover crop needs to either be tilled into the soil or killed and left to decompose on the soil surface.  If the cover crop is removed, most of the nitrogen benefit is removed with it.  With a low carbon to nitrogen ration (C:N) legumes break down quickly, releasing the nitrogen into the soil.

However, if the purpose of the cover crop is to increase organic matter in the soil, legumes aren’t the best choice.  Grasses grow quicker, contain a higher C:N ratio, and produce more biomass.  As they break down, they increase soil organic matter content making them a better choice for increasing organic matter.

There are legumes and grasses that can be used for either cool or warm season cover crops.  It seems the choice would be as simple as just choosing which cover crop to grow.  But wait, there’s more to the equation than simply answering the question, “Do I want to grow a grass or a legume?”

Did you know, for instance, some cover crops suppress weed growth?  It’s true!  Many cover crops can shade weed seed and prevent them from germinating due to lack of light and competition for water and nutrients.  Some cover crops also have an allelopathic affect on certain weeds.  For example hairy vetch and velvetbean suppress yellow nutsedge.  Cereal rye has been reported to suppress redroot pigweed and common ragweed.  Crimson clover and hairy vetch suppress the growth of pitted morningglory.  These cover crops somehow release allelopathic chemicals (chemicals that stop the growth of other plants).  This means if there is a particular weed that’s been troubling your garden, lets say lambsquarters, then you may want to consider planting hairy vetch or cereal rye to suppress the growth of this weed.

Some gardeners call with the question of how to control root knot nematode.  Some cover crops suppress nematodes.  Research has shown that pigeonpea, crotalaria, hairy indigo, velvetbean, joint vetch, and sourghum-sudangrass reduce root knot nematode numbers in the soil.  This same research also showed that these crops had no effect on sting or lesion nematode numbers in the soil.  This indicates the need to do a nematode assay to determine which nematode is causing the problem.

Another consideration when choosing a cover crop is insect management.  A cover crop can be a haven for both pests and beneficial insects.  One study mentioned in my reference showed that rye used as a cover crop reduced fruitworm populations, but increased the number of stinkbugs found in the tomato crop that followed.  On the other hand several studies have show an increase in beneficial insects such as lady beetles, big-eyed bugs, assassin bugs, and other beneficial insects following crops such as clovers and vetches.  The beneficial insects may be drawn to the pollen, nectar, honeydew, and other insects to prey on, along with the shelter provided by these cover crops.

Whether you have a large garden of acres or a small garden such as a 4’ x 4’ raised bed, cover crops may offer a benefit to both soil nutrition and insect management for the home gardener.

Reference:

Cover Crops for Organic Farms: AG-659W-03

http://www.cefs.ncsu.edu/resources/guides/organicproductionguide.html

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FEATURE PLANT

Elephant Ears

Alocasia vs. Colocasia

By Tina Stricklen

Do you have elephants in your garden?  I’m not talking about the four-legged behemoth mammals, but the plants.  Elephant ears are excellent plant material if you want to add a lush, tropical feel to your garden.

There are two types of elephant ear: Alocasia and Colocasia.  The simple difference between the two types is in which direction the leaf grows.  For Colocasia, the long heart-shaped or arrowhead-shaped leaves point toward the earth.  If the leaves grow upright then you’ve got an Alocasia.  Technically, the genus Alocasia differs from Colocasia in leaf and ovary characteristics.  In most cases, Alocasia species have shiny leaves while generally speaking, Colocasia have matte leaves.

Back in the day, elephant ears were pretty hard to find, and when you did find them, they were typically the straight green variety.  Today, plant breeders have developed specimens with a variety of interesting characteristics.  They include colorful stalks, prominent veining, various leaf colors and markings, as well as varying heights and sizes.

One such breeder is Dr. John Cho, a plant pathologist at the University of Hawaii.  He has used his knowledge of breeding disease-resistant edible Colocasias to develop a line of ornamentals to help answer the demand for more variety.  These include ‘Hilo Bay’, ‘Hawaiian Eye’, ‘Maui Gold’, and ‘Pineapple Princess’, to name a few.  If you are just starting your collection, there are some common cultivars to whet your appetite.  They include ‘Illustris’, ‘Black Magic’, and ‘Chicago Harlequin’.  If you are really adventurous, you should try ‘Thailand Giant’ because it can reach nine feet in the wild but probably about five to six feet in our climate.  Alocasias have not been as widely used in our area as their counterpart, but they are starting to gain some footing in the trade.  Why not give Alocasia macrorrhizos or Alocasia wentii a try?

Aside from lack of availability, hardiness has been an issue for some gardeners.  Most of the aforesaid varieties are hardy to zone 8, but there are a few that push the zone to 7b or lower.  Be sure to read the labels when you shop, and as an insurance policy you can lift the tubers and store them in a dry basement or cool garage over the winter.  Colocasias make good marginal aquatic plants, but you will want to take them out of the water and store them before frost.  If you leave those zone 8 plants in the ground, be sure to mulch heavily and remember where you planted them because they don’t re-emerge until late spring or early summer.  Since elephant ears are tropical and sub-tropical plants, they like hot, muggy weather making them an excellent choice for our Johnston County gardens.  They grow well in humus-rich soils, in full sun to light shade and are very heavy feeders.  With this smorgasbord of elephant ears, it won’t be easy to choose just one!

Sources:

http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/bulbs-summer/colocasia.html

http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/water-garden/marginalaq/colocasia_esculenta.html

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UPCOMING EVENTS

The Food Dialogues(R): North Carolina -
Raleigh Convention Center, 500 S. Salisbury St., Meeting Room 302, Raleigh, NC 27601 on Thursday, September 19, 2013 from 11am – 2:30pm.  Registration:  10am – 10:45am.  This event is hosted by the U.S. Farmers & Ranchers Alliances(R) and the North Carolina Animal Agriculture Coalition.  Lynda Loveland, Co-Host  of the MIX Morning Show will be the moderator.  Questions will be answered regarding the foods we eat, and the farmers that feed us.

Southern Ideal Fall Home Show -
September 27 – 29, 2013 at the North Carolina State Fairgrounds, 1025 Blue Ridge Rd, Raleigh, NC 27607 : Admission: $9 at the door, or for special tickets such as Friday’s senior tickect and hero day, or Saturday’s Game Day Discount visit their website.

Extension Master Gardener Volunteers will at Clayton Farm and Community Market in Clayton on Saturday, Sept. 21st from 9am to 1pm to answer questions and help diagnose pest problems.

For accommodations for persons with disabilities, contact Bryant Spivey at 919-989-5380 no later than five business days before the event.

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YARD VILLAIN

White Grubs

By  Shawn Banks

White grubs are the larval stage of several different beetles in our area including masked chafer, Asiatic garden beetle, southern masked chafer, green June beetle, and the all important Japanese beetle.  There are a few other beetle species which produce white grubs, but generally their numbers are low enough not to cause much damage to the turf.

Damage caused by white grubs can be direct or indirect.  The direct damage white grubs cause is from either feeding on the root system of the grass, or by the burrowing inside the roots and uprooting the grass.  Indirectly they damage the grass by attracting wildlife such as moles, raccoons, skunks, and birds that dig up the grass looking for a grub meal.

Between the months of May and August, adult beetles are usually out flying around looking for soft soil where they can dig in and lay their eggs.  The timeline varies depending upon the species of beetle.  When we have a lot of rain, like we have had this year, the soil is soft nearly everywhere.  Most years the beetles will find it easier to dig into soil that is irrigated.

Before purchasing a chemical to control grubs it’s a good idea to verify you actually have them.  To do this, dig a 1-foot square, about four inches deep, and look for the grubs among the roots of the grass.  Do this in five to ten locations in the lawn to get an average of how many grubs are in the turf.  If there are five or more per square foot, it might be a good idea to treat the lawn.

A biological treatment that is only good for Japanese beetle grubs is the use of milky spore disease.  For all other species of white grub look for a grub control product at your favorite lawn and garden center.  There are granular products and liquid products.  They are both very effective when used according to the label directions.  Be sure to read the directions as some of them will need to be watered in so the chemical will get down in the soil to the grubs.

It takes less chemical to kill grubs while they are small and near the soil surface.  When we look at the life cycle of most grubs, this will be when they are first hatched from the egg.  Early August to mid-September should be an excellent time to successfully treat for white grubs.  If treated in the fall of the year, there is no reason to treat again in the spring, as there shouldn’t be any grubs left to treat.

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WHAT’S IN SEASON

PECAN

By Laura Taylor

I can already feel it! Can you?  Even during the sweltering heat of August I can always sense the coming of fall.  Sometimes the air becomes cooler in the evenings and sometimes the humidity falls off just a bit, but mostly it’s a sense from somewhere deep in my childhood…a sound, a smell…

Are you familiar with the saying, “You don’t know what you’ve got ‘til it’s gone”?  I experienced it when I was in the Navy.  I grew up in Texas where pecans were plentiful.  In fact, not only was the pecan tree our official state tree, Texas is the largest producer of native pecans (second only to Georgia in hybrid production).  Pecans were everywhere in Texas; we would pick them in the wild to make pies and to eat as snacks.  As a sailor travelling the world, I soon realized how lucky I was to have had pecans literally at my fingertips.  Finding fresh, sweet pecans in my travels was often difficult and expensive.

Pecans were not what drew me to North Carolina when I retired from the service, but I was glad to find that one of my favorite nuts was in abundant supply in my adopted state!

In any case, the potential for late frosts and the limited number of late-maturing varieties limits the growing season in North Carolina, but I’ve never had a problem finding these delicious treats when time came to make pecan pies for the holidays or anything with sweet potatoes in the fall. Getting back to the start

of my story, though, I’m not the only creature that can sense the coming of fall and with it the ripening of pecans.  While squirrels can be formidable competition for the pecans, August also brings a variety of insects wanting various parts of your prized trees.

The insect of biggest concern is perhaps the pecan weevil. The weevil grub pupates underground from winter to August – or can stay up to two years! They emerge as adults in August and with only days to live; they grab a mate and climb a pecan tree, where the female drills a hole into the pecan to lay eggs. As the pecan develops, the hole closes.  As the larvae develop, they eat the pecan flesh and when the fruit falls from the tree, they eat their way out of the shell and burrow underground to live until it’s their time to make their way up the tree.  It should be noted that some pecan weevils do fly, but the vast majority – about 90% – climb the trees in pursuit of the egg laying opportunities.

Other pests of minor concern to pecan trees in North Carolina include twig girdlers, aphids, and stink bugs.  Stink bugs bore into the nut causing it to fall prematurely from the tree or for the flesh to be bitter.  Like the weevils, stink bugs emerge in the spring to lay eggs and then attack pecans as adults before wintering over in the orchard.  Twig girdlers do just that, girdle twigs, causing them to break off when the wind blows.  On the ground, larvae feed inside the branch and then move to the soil to pupate.  Aphids suck juices from the leaves and deposit honeydew on those below.  Sooty mold grows on the honeydew causing the leaves to turn black and often fall early from the tree.

Besides sooty mold, pecan scab is the other main disease suffered by pecan trees in North Carolina.  This fungus hits early in the season and attacks immature leaves causing circular spots to grow, the leaf to deform, and potentially reduces photosynthesis.

Control and prevention is the best way to manage pests and disease.  First, keep the area clean of debris, twigs, and grasses or other crops that provide housing for these pests.  Next, monitor for the presence of insects and disease, and then if discovered, use an appropriate fungicide or insecticide.

Harvest pecans when they fall to the ground.  Then, because the relatively high oil content in pecans can cause them to spoil, store them at 32 degrees for up to one year or in the freezer for longer periods.

Recipe: Mississippi Spiced Pecans (from eatingwell.com: http://www.eatingwell.com/recipes/mississippi_spiced_pecans.html)

Ingredients:

• 1 pound pecan halves
• 1 tablespoon packed dark brown sugar
• 1  teaspoon kosher salt (adjust to taste)
• 1 teaspoon chopped fresh thyme
• 1 teaspoon chopped fresh rosemary
• ½ teaspoon freshly ground pepper
• 1 pinch cayenne pepper
• 2 tablespoons extra-virgin olive oil

Directions

1. Preheat oven to 350°F.
2. Spread pecans on a large baking sheet. Roast until fragrant, about 12 minutes. Watch carefully so they don’t burn.
3. Combine brown sugar, salt, thyme, rosemary, pepper and cayenne in a small bowl. Transfer the roasted pecans to a large bowl, drizzle with oil and toss well to coat completely. Sprinkle with the spice mixture and toss again. Serve warm or let cool completely and store in an airtight container for up to two weeks.

Resources and recognition

1. Recipe found on http://www.eatingwell.com/recipes/mississippi_spiced_pecans.html)
2. Information came from multiple sources, including:

• http://www.ces.ncsu.edu/depts/hort/hil/ag81.html
• http://en.wikipedia.org/wiki/Pecan

http://www.lsjunction.com/tree.htm

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GARDEN TECHNOLOGY

Apple App of the Month

By Karen Damari

Hello!  It’s time for another interesting garden app for the iPad.  As any serious gardener knows, there are a plethora of unique terms used to describe the various aspects of gardening:  conifer, adventitious, rill… it’s almost impossible to remember them all.  A nice app I found is Garden Terminology Glossary by sun-scroll.com.  It has an index allowing you to scroll alphabetically through the entire glossary; select a random term to learn about that day, or search a specific word.  You can add words to your ‘favorites’ (there are always a few words I come across frequently and yet can’t set straight in my mind), as well as keep a history of terms you’ve looked up before.  It’s easy to navigate the app, and you can scroll down the entire list quickly… even with an iPad 1(like mine).

The terms are those used in British gardens and gardening, which makes for a few differences and includes some terms not usually found in American gardening (privy garden means ‘private’ and thus a private garden, usually made for the sole use of a king or queen), but even those differences can be interesting to learn.  It has an extensive vocabulary (more than 575 terms) of not only plant terminology (lateral meristem is a region where cells divide, located along the length of a stem or root), but words used in landscaping (rill is a small water course), architecture (The Corinthian order has bell-shaped capitals decorated with acanthus leaves), and insects (Hymenoptera is an insect family make up of species having 4 membranous wings, of which the front pair are larger. Includes bees, wasps, sawflies, and ants).  It has many lovely terms I had never heard of (Pomarium is a medieval term for an apple orchard) and delighted in learning.  I’m now calling my 3 apple trees a Pomarium.

Some negative aspects are that it doesn’t have every term I need or the ability to add those terms, and it hasn’t been updated since it came out in 2011 so I’m guessing the creator has no designs on adding vocabulary.  Also, it doesn’t have pictures, which is probably one of the reasons the app is fast, but there are times I’d like to see an example of what I’m investigating.  All in all, however, I find it a very useful app and would recommend it to any gardener.

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SEPTEMBER GARDEN TASKS

GENERAL IDEAS


Collect soil samples for testing, so that you’ll know how much fertilizer and lime to add this fall. Test your lawn, flower beds and vegetable garden.  Testing should be done once every 3 years.  We have FREE kits.

Clean up and throw away any diseased plant material.  Do not throw it in a compost pile.  Leaving infected plant material on the plants or where it fell on the ground provides a source of re-infection for next year.

LAWN CARE


Tip for fertilizing cool-season (i.e. fescue) lawns: Fertilize on Labor Day, Thanksgiving & Valentine’s Day. Fescue lawns are green & growing during the cool months of fall, winter, and spring. Use a slow-release fertilizer.

Plant fescue seed to fill in bare spots or rejuvenate your lawn. The best time to plant fescue seed is Sept. 15 – Oct. 15.  Contact us for a publication on lawn care and renovation and get your soil samples in!!

Overseed common Bermuda grass lawns with ryegrass in late September – to keep lawn green all year.

Control winter weeds with a pre-emergent herbicide applied around mid-September on lawn and shrub plantings.

TREES, SHRUBS & ORNAMENTALS


Prepare plants for dormancy. Plants need time in the fall to slow down & prepare for the winter, so do not apply nitrogen (N) fertilizer or prune after July.  Consider applying potassium (K) fertilizers, which increase winter hardiness.

Divide spring & summer-blooming perennials – such as daisies, daylilies, creeping phlox – that are overgrown. This is an easy way to enlarge your garden without purchasing more plants. Dig the plants, gently separate into smaller clumps & replant immediately. They’ll have plenty of time to get re-established before next spring.

Set out cool-weather annuals for winter color. In addition to pansies and ornamental cabbages, other cool-weather ornamentals such as Dianthus, snapdragons, dustymiller, and ornamental sage look great throughout the winter. Wait to plant spring bulbs till chillier fall weather arrives.

VEGETABLES & FRUITS


Start fall vegetables such as lettuce, spinach, collards, and cole crops to fill in spaces in the vegetable garden.

Mulch Peppers.  Be sure to mulch the plants to keep the roots cool and moist. Stake plants if you like, or you can allow them to tumble over onto ground that is covered with a thick blanket of hay, straw, or even newspapers.

LANDSCAPE IDEA


Think ahead to next fall and consider plants that will provide autumn color. Trees such as ginkgo, red maple, southern sugar maple, Japanese maple, sourwood, crape myrtle and tulip poplar have outstanding autumn foliage color. The flowers of Sasanqua camellias and autumn-flowering chrysanthemums contribute much to the colorful autumn scene. Don’t forget the brilliant red foliage of rabbiteye blueberries. The berries of pyracantha, nandina, viburnum, beautyberry and many hollies provide bright accents into winter. Look for interesting plants in the nurseries, and add them this fall.

HOUSEPLANTS


Plan to bring houseplants and tropicals indoors when temperatures dip below 50 F. Move plants into partial shade for a week to condition them to lower light levels indoors.
 Prune them, if necessary, to a manageable size. Give them a good bath in soapy water or spray with insecticidal soap to keep insect pests from moving indoors with them.
Give tropical plants as much light as possible once they are indoors.

Prune them, if necessary, to a manageable size. Give them a good bath in soapy water or spray with insecticidal soap to keep insect pests from moving indoors with them.  Give tropical plants as much light as possible once they are indoors.

*** If you would like to receive this newsletter monthly via email, send an email to shawn_banks@ncsu.edu asking to be added to The Gardener’s Dirt email list.

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If you have gardening questions you would like to have answered contact the Extension Master Gardener Volunteers by phone at (919) 989-5380 or by e-mail at jcemastergardener@gmail.com.

If you would like to subscribe to this monthly newsletter send an e-mail to shawn_banks@ncsu.edu and ask to be added to the electronic newsletter list.

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