Changsha Mandarins: Their Fruit and Their Pests

About four years ago I planted three Changsha Mandarins in my backyard.  Changsha Mandarins (one of the many varieties within Citrus reticulata) are one of the cold hardiest of the citrus family that do not have any Poncirus or Ichangensis in their bloodline.  While this reduces the Changsha's survival in truly cold winter climates, it also means there will be none of the characteristic skunkiness or insipid, puckering flavors that sometimes go hand-in-hand with the entire notion of cold-hardy citrus.

Compared to Satsumas (which otherwise share many of the Changsha's characteristics) my Changsha Mandarins are tall, upright trees, very different from the drooping shape of the Satsumas.  Their vertical growth has been nothing short of spectacular as seen in the photos below:

Changsha Mandarin in 2009.  Total height
about 1.5 feet tall.  It was moved from a
pot to the ground in early April.

Changsha Mandarin in 2010.  Total height
about 3 feet.  It's still mainly a single
shoot at this point, with a few side-
branches just forming.

Changsha Mandarin in 2011.  Total height
about 7 feet.  The single vertical branch
is starting to divide out into multiple
branches.

Changsha Mandarin in 2012.  Total height
about 11 feet.  This particular tree has
17 fruits on it, its first crop ever!

This Spring (2012) I observed flowers covering all three of my Changsha Mandarins, and many of the flowers successfully set fruit.  I was initially disappointed at what appeared to be the small number of fruit on the trees, but as summer wore on I discovered dozens more fruit than I initially saw during the spring.  Now here at the end of September as the fruit are beginning to acquire their first hints of orange color, I can easily count them:  there are 52 covering the three trees.

My first crop of Changsha Mandarins!  Late September 2012.

Since I'm still about a month away from sampling my first Changsha Mandarins I can't give any first-hand experiences with the fruit yet.  The largest are just a bit smaller than tennis balls.  Here's the description from the website of the nursery I bought them from, Woodlanders in Aiken, South Carolina:  "It is a hardy and early fruiting citrus here in Aiken, SC with fruit which is much relished by neighborhood kids!"  

At the Southeastern Palm Society's Citrus Expo held here in Wilmington in November 2010 I had the pleasure of actually meeting up with some folks from Woodlanders Nursery, and I asked them about their Changshas in particular.  I was assured their trees produced excellent, although sometimes seedy fruit.  I look forward to confirming this next month!  Note: All of the citrus from Woodlanders Nursery is grown on its own roots.  This means without a dwarfing rootstock you're likely to get a very large tree as the years ago by.  Plan accordingly!

Changsha Mandarins, as with all citrus, have a few pests you've really got to watch out for.  Here in North Carolina, several hundred miles north of the Florida or Gulf Coast citrus industry, our insect and disease pressures are much lower than backyard or hobbyist growers to my south might endure.  The three insect pests I've observed here are the Citrus Leafminer, Red Citrus Spider Mites, and several varieties of Aphids.

Citrus Leafminer damage.  The
tiny caterpillar inside the leaf
causes the shiny U-shaped trails.

The Citrus Leafminer is active only during the warm, growing season.  The adults are small, unimpressive moths that blend in really well with any of the dozens of moth species you might see flying around streetlights and porch lights at night.  The adults lay their eggs on tender new growth.  The eggs hatch into tiny caterpillars that tunnel inside the new leaves, leaving a very characteristic shiny trail behind that doubles back on itself many times in U-shaped channels as they consume the tasty, inner portion of the leaf.  In most cases the damage they cause isn't severe and probably only becomes a major issue on small or otherwise unhealthy trees.  For control of Citrus Leafminers I visually inspect new shoots every couple of days during the growing season and just pull off and safely dispose of any affected leaves.  If you catch them early enough this should prevent a major outbreak.  I went three years without seeing a single Citrus Leafminer using this method!  Obviously this would not work as in areas near commercial citrus plantings or where nearby neighbors are growing citrus.  Chemical-based or pheromone-based control techniques might work better then.

When a Citrus Leafminer caterpillar is ready to pupate it rolls over a section of leaf and seals it with silk.
These are very important to remove and destroy if you're wanting to exercise chemical-free control of these pests.

The only picture I could find I've taken of Red Citrus
Spider Mites.  There are a few individuals on the leaf
behind the flower buds, and a few more above.

Red Citrus Spider Mites are, at least in my backyard, almost exclusively a Winter and early Spring pest.  They can multiply to astounding numbers during the winter and can heavily damage leaves by their sucking of sap and subsequent dehydration of the leaves.  Interestingly they don't appear to be affected by freezing temperatures even down to 20 degrees F. (-6.5 degrees C)  They congregate most-heavily on the upper surfaces of the leaves but also appear on the lower surfaces in smaller numbers -- look for tiny red dots a little smaller than grains of sand.  If you wipe your finger across them on a leaf surface you'll crush sometimes dozens at a time leaving a pale pinkish streak behind.  I imagine the reason these spider mites are such a problem during the winter is whatever predators may control their numbers during the warmer two-thirds of the year are dormant or absent in winter.  During the summer I rarely, if ever, seen them.  Some control can be achieved by using a horticultural oil spray, but the amount of spray needed and the time spent coating both the upper and lower leaf surfaces could both become enormous if you have more than a few trees.  Be careful using oil spray in the days leading up to a major cold outbreak as it appears the oil can negatively impact the leaves' ability to handle temperatures below 27 degrees F (-3 degrees C) for any length of time.  There are probably chemical control methods that also would work, but I strongly prefer to remain organic in all my gardening endeavors.  

Aphids infesting the undersides of Changsha
Mandarin citrus leaves.

The final citrus pest I've observed in my backyard are Aphids.  If you've raised apples, roses, peaches, or almost anything you've probably experienced outbreaks of Aphids when a plant is producing lots of tender, new growth.  I'm not sure precisely what Aphid species I have on my citrus trees but they follow the pattern observed in other plants exactly:  when a flush of new growth is occurring Aphids numbers will explode for a few weeks, diminishing and then virtually disappearing as the new growth hardens off into mature leaves.  I list Aphids last because they've seldom been a significant enough pest to worry about, and I have taken no actions to prevent or disturb Aphids on my citrus so far.

Long-tailed Skippers

Long-tailed Skipper feeding on Lantana.  Note the blue back, the twin
tails, and the multiple clear "windows" on the wings.

One of the prettiest butterflies to visit my backyard arrives in increasing numbers each July and August:  Long-tailed Skippers.  (Urbanus Proteus)

They spend the winter in frost-free regions of southern Florida.  As the weather warms in the spring the butterflies spread north across the Southern United States to take advantage of additional food sources and less competition with other butterflies.




Over the past several years I've noticed the first Long-tailed Skippers arriving in my backyard in July and early August, but it's the month of September where numbers of these butterflies really increase.  On a recent day in late September I counted six Long-tailed Skippers simultaneously scattered across a single eight-foot wide planting of Lantana.

Long-tailed Skipper

Long-tailed Skippers will utilize almost any available flower for nectar.  For reproduction they seek out plants in the bean family, including many cultivated garden beans, on which to lay their eggs.  This can make them an agricultural pest in some areas.  In my backyard the naturalized Chinese Wisteria serves as a very effective larval food source and may be the birthplace of some of my late-season butterflies.

One thing that makes this butterfly so striking is the deep blue coloration on its back.  In certain light angles there appears to be a shimmering iridescence associated with the blue.  Many insects and even some birds utilize iridescence, a physical refracting of light, rather than true coloration based on pigments.  Just think of the silvery iridescence of a dragonfly's wings or the metallic green on a hummingbird's back.

Long-tailed Skipper viewed from the side

The number of Long-tailed Skippers in my backyard begins to diminish by mid October as the butterflies sense the shortening days and cooler nighttime temperatures and they migrate south to Florida.  By early November we typically haven't had our first frost yet but the Long-tailed Skippers are gone, safely moving toward the south side of the winter freeze line in Florida.

The Constellation Orion

If I spend time outdoors looking up, it's usually looking for birds or admiring the clouds.  I happened to wake up before the sun this morning and noticed an "old friend" low in the southeastern sky:  it's the constellation Orion.

Orion is one of the most recognizable constellations in the sky even to casual observers.  The three bright stars in a short, straight line make it easy to find.  Orion is above the horizon for the entire Northern Hemisphere winter season, and since it's located near the ecliptic (roughly five degrees off the celestial equator) virtually all of the Earth can see Orion at some point during the year.

If you've got binoculars or even a low-powered telescope look for the Orion Nebula, a region of gas and dust glowing in space; it's located just "below" the line of three bright stars in Orion's belt.  Thousands of new stars are forming within the nebula, and given how much unconsolidated material is present in the nebula new stars should continue to form for a very long time.

My view looking southeast this morning around 5:30 am.  The three bright stars near the middle of
the photo make up Orion's belt:  Alintak, Alnilam, and Mintaka.  The Orion Nebula is a few degrees below
the "belt" and looks like a reddish smudge in this image.

Google Earth's view of Orion, showing the imaginary lines connecting the brighter stars in the constellation.  

Cicada Killer Wasp

I had the rare treat of watching a literal life-and-death struggle take place in my backyard back in August.  The battle was between two large insects:  a Cicada and a Cicada Killer wasp.

The shed skin from a Cicada, left clinging on
a Dogwood tree limb.

We're all probably pretty familiar with Cicadas.  They're large, usually dark-colored insects that emerge during the summer months.  Even when they're not seen they're always heard; a loud, grating buzzing sound that can drown out conversation -- and sometimes even the neighbor's lawn mower!  The Wilmington, NC area primarily has Annual Cicadas that emerge in modest but predictable numbers each summer.  Annual Cicadas spend most of their life underground feeding on sap from tree roots until environmental cues (mainly soil temperature) tell them it's time to tunnel up to the surface.  The soft-bodied larva then climb a tree trunk where they literally split their skin, crawling out as an adult.  After a time drying their new wings and soft, new skin they're ready for their short life as an adult, mainly spent feeding on tree sap, mating, and for the females, laying eggs.  This year I first noticed a number of adult Cicadas in July, although a relatively large number of newly-shed skins were recently noted clinging to tree trunks even now in mid-September.

Southeastern North Carolina doesn't appear to share in the large outbreaks of the Periodic Cicadas that occur at 13 or 17 year intervals in other parts of the Eastern United States.  These amazing creatures have developed a synchronized schedule to their emergence from their underground larval form that results in huge numbers of adult Cicadas appearing at regular intervals.  This is believed to be advantageous for the Cicadas since their tremendous numbers overwhelm all possible predators, leaving plenty of adults to mate, lay eggs, and ensure the survival of the Cicadas for another generation.  The BBC has a wonderful nature documentary (featuring the venerable David Attenborough) profiling the 17-year Cicadas and their successful reproductive strategy.  A good resource for tracking these long-lived broods of Periodic Cicadas is here at CicadaMania.com.  Perhaps you live in an area that is frequented by these insects.

Now, back to my backyard in the middle of August.  I was actually attempting to photograph some butterflies when a Cicada's frantic buzzing alerts me to look up into my Magnolia tree.  I watched as a Cicada spiraled down ungracefully into my garden, thrashing on the ground.  I ran over to get a better look and saw another very large insect struggling with the Cicada:  this was my first look at a Cicada Killer wasp.  Native to the Eastern United States, Cicada Killer wasps emerge around the same time as the adult Cicadas.  They crawl along tree trunks and branches searching for Cicadas, at which point they tackle the unsuspecting insect and sting it with a paralyzing poison that leaves the Cicada alive, but immobilized.

Cicada Killer wasp, dragging the Cicada
up to a higher perch from which
she can become airborne.

Cicada Killer wasp administering a sting

The clearest picture I got of the Cicada Killer wasp and her prey, a paralyzed Cicada.

Now here's the amazing part:  we know as far as insects go Cicadas are pretty massive.  The Cicada Killer wasp picks up the paralyzed Cicada using its legs, and struggling with every ounce of its strength flies off with it.  Its destination?  A small pit dug in the ground earlier where the wasp will bury the Cicada.  A single egg will be laid on the Cicada which will consume the insect as food.

Cicadas and Cicada Killer wasps -- "Nature" certainly doesn't pull any punches!

Bird Migration Cranking Up!

My work schedule has kept me from spending as much time watching the Fall migration season unfold, but I've still managed to see a few interesting birds in my backyard.  A couple of cold fronts in the past 10 days have allowed northerly winds to develop across the Eastern U.S. which is very advantageous for southward-migrating birds.  Commercial airline pilots know how easy it is to save fuel by finding a tail-wind and sticking with it, and migrating birds are certainly no different.

male American Redstart

Although the picture is horrible, this first bird pictured here is a newcomer for my backyard:  A male American Redstart.  I saw the female of this species briefly several years ago during the Fall migration, but this is the first time for the male.  He spent several minutes fluttering around from tree to tree, once flying just 10 feet over my head, then landed in an Azalea bush only 15 feet from me where this picture was taken. American Redstarts are a type of wood Warbler that breeds in the deciduous forests of Eastern North America and Southern Canada, then winters mainly in Central America.

Red-eyed Vireo

The Red-eyed Vireos are still present in small but predictable numbers.  These birds normally peak in numbers here the last week of September and the first week of October.  Red-eyed Vireos do breed in Southeastern North Carolina, but I've never seen them locally except during the Fall migration.

Red-tailed Hawk

And probably not a migrant, but this Red-tailed Hawk caught and ate a House Finch from near my backyard feeders one week ago.  After catching the bird and taking his catch up to the roof of my house, he flew into a nearby tree where he dismembered and ate the finch, all the while a literal snow of tiny feathers fluttered down into my front yard.









Fall-migrating birds should peak in numbers and in species-diversity in the next two weeks -- I'll be watching!

Carnivorous Garden

Venus Flytrap

Like most of us, I once assumed a plant that actually eats things must live thousands of miles away in some exotic, tropical rain forest surrounded by howling monkeys and other things I can't name.  The truth is actually stranger than this assumption:  many carnivorous plants are right at home here in Southeastern North Carolina.  In fact the most famous carnivorous plant of all, the Venus Flytrap, is native to just a few boggy areas within a 90-minute drive of Wilmington.


A carnivorous plant is a plant that traps and digests insects for food.  Most plants don't have to resort to such extreme measures since they can derive everything they need for life from sunlight and soil they grow in. Eastern North Carolina has very mineral-pool soils; a good portion of the Coastal Plain of the state is either bright white beach sand or black organic peat, both of which contain very few beneficial minerals that plants need.  Heavy rainfall leaches minerals from the upper layers of the soil leaving only the non-soluble sand or peat behind.

Carnivorous plants are at home in waterlogged black organic peat soils.  These boggy areas are technically called pocosins, an Algonquin Indian word that means swamp on a hill.  The Nature Conservancy has been instrumental in protecting these rare areas, and the plants and animals that depend on them, from destruction. Their Green Swamp Preserve in Brunswick County and Shaken Creek Preserve in Pender County contain wonderful examples of the plant diversity that exists in Southeastern North Carolina.  The Wilmington office of the Nature Conservancy maintains a very informative blog detailing the natural wonders of this part of the state here.

Pitcher Plants in the
Green Swamp Preserve

It would be criminal if I didn't at least try to raise a few carnivorous plants in my yard.  The Nature Conservancy folks actually helped me out in this regard:  my family and I participated in a guided tour of their Green Swamp Preserve this spring and as parting gifts received a couple of Venus Flytraps.  It's a federal crime to remove these endangered, protected plants from their natural environment, so the plants we received were cloned in a laboratory at Southeastern Community College in Whiteville, NC.



We took the two Venus Flytraps, added a couple of Pitcher Plants bought at a local farmer's market, plus a few Sundews I saved from destruction at a construction zone at the Wilmington airport, and created a backyard Carnivorous Garden of my very own.  With just a few plants to start with the entire "garden" only measures about 1 x 2 feet across.

My tiny Carnivorous Garden

Pitcher Plants and Sundews both grow wild in the same boggy, mineral-poor soils where Venus Flytraps grow, but they are less exacting in their climate requirements and can grow in many areas across North America from Canada to Mexico.  I bought a small bag of peat from the local garden center but knew that my sandy backyard soil would drain too quickly to support the carnivorous plants.  My solution was to create a "perched" water table by digging down about six inches and adding a layer of cat litter about one-inch thick with a raised lip around the edge.  Most cat litter is made of an impermeable clay called Bentonite.  Rain water percolating down through the peat collects in this clay "tray" and creates a miniature bog, perfect for growing carnivorous plants.

Carnivorous plants are adapted for areas with very mineral-poor soil.  That means you should never add fertilizer and never water these plants with tap water or well water.  The dissolved mineral content will damage and eventually kill the plants.  Pure rainwater is definitely the way to go.

There do exist tropical carnivorous plants that I could never grow outdoors here due to the freezing temperatures we receive during the winter.  The varieties of carnivorous plants I'm growing actually require a period of cold weather just like many temperate trees do, or else they eventually die.

Here are a few photos of my Carnivorous Garden plants:

Yellow Pitcher Plant

A Purple Pitcher Plant.  The downward-pointing hairs don't allow crawling insects to perch and they fall into a pool of water deep within the curled-up leaf.  The minerals from the insect's decaying body then feed the plant.

A Venus Flytrap growing in my Carnivorous Garden.  There are tiny guard hairs inside each trap.  If two or more
 hairs are triggered by an insect within a short period of time, the trap closes, killing and digesting the insect.

A small collection of native Southeastern North Carolina Sundews.  The sticky spines on the leaves attract, then entrap small insects.  The minerals from the insect's bodies are absorbed to feed the plant.

Sunday Afternoon Birdwatching

Summertime heat and humidity continues even now that we're in September.  Today's high of 92 occurred just before a series of thunderstorms dropped around two-thirds of an inch of rain.  I managed to watch the feeders and trees behind the house closely for a little over an hour this afternoon before and after the storms.

One of my favorites backyard birds is the Brown-headed Nuthatch.  (Sitta pusilla)  They're native to the Longleaf pine forests that covered most of the Southeastern Coastal Plain before European arrival in North America.  Fortunately there are enough remaining Longleaf Pine trees in my neighborhood to allow a population of these birds to persist.  Brown-headed Nuthatches are tiny birds (usually under 4 inches in length) and along with the Pygmy Nuthatch (a western U.S. bird) are among the smallest nuthatches on earth.  They're active, inquisitive, and very talkative birds with a call that sounds like a stereotypical bathtub rubber duck toy.  They enjoy either suet or sunflower seeds and are resident here year-round.  If you're familiar with the perky nature that Titmice and Chickadees display you're halfway there to anticipating the behavior of this bird.

Brown-headed Nuthatch on the suet feeder

Brown-headed Nuthatch (same individual as in the other picture)

Brown-headed Nuthatch perched in our Magnolia tree

As always I post these sightings over on eBird so researchers and other birders will have access to my lists  now and into the future.  Here's today's list:

15 species total

2	Mourning Dove
2	Ruby-throated Hummingbird
1	Red-bellied Woodpecker heard only
1	Downy Woodpecker Heard only
3	Red-eyed Vireo
1	Blue Jay
2	Carolina Chickadee
3	Tufted Titmouse
3	Brown-headed Nuthatch
2	Carolina Wren
3	Northern Mockingbird
1	Brown Thrasher
3	Northern Cardinal Age & Sex Juvenile Immature Adult Age Unknown Male 1 Female 1 Sex Unknown 1
4	House Finch Age & Sex Juvenile Immature Adult Age Unknown Male 1 1 Female 1 Sex Unknown 1
5	House Sparrow Age & Sex Juvenile Immature Adult Age Unknown Male 2 Female Sex Unknown 3

Some other very common birds I got pretty good photos of today are the Ruby-Throated Hummingbird and the Tufted Titmouse:

Ruby-throated Hummingbird on the clothesline

Tufted Titmouse with a sunflower seed.  This
appears to be an immature bird born earlier this year.

Yuzu - A Cold-hardy and Very Unique Citrus

I've found I enjoy raising fruit trees more than I enjoy vegetable gardening.  The maintenance requirements of fruit trees are typically much lower, there's very little weeding involved, and virtually all fruit trees look great in your yard.

North Carolina-grown Yuzu citrus

If folks in the Carolinas plant a fruit tree they typically choose a peach or apple tree.  I've got those too, but my love of all things tropical got me wondering just how exotic I could go right here in North Carolina.  A few Google searches back in 2007 led me to Stan McKenzie of McKenzie Farms in Scranton, South Carolina.  Stan is the "Johnny Appleseed" of citrus for the Southeastern U.S. outside of Florida.  Over the past couple of decades he has experimented with different varieties of citrus and has identified which ones can survive our winters.  He's also developed tried-and-true techniques of protecting citrus during hard freezes using microsprayers and water barrels -- both techniques utilizing the latent heat released from water as it freezes to protect the trees.

Confirmation that his citrus varieties and growing techniques work well came in the horrible winter of 2009-2010 when the temperature at his South Carolina farm dipped to 14 degrees F on three consecutive nights.  Cold of this magnitude would have utterly destroyed a citrus grove in Florida, but Stan's trees survived and even set fruit the following summer!

One of the trees Stan sold me is a unique variety called the Yuzu. (Citrus ichangensis x Citrus reticulata)  In English, it's a hybrid between the Ichang Papeda (a very cold-hardy citrus from China) and the Mandarin Orange.  Yuzus were first hybridized either purposely or accidently in China, but have achieved much more popularity in Japan and South Korea where culinary uses have been developed for its aromatic zest, juice and rind.  This is detailed in the Wikipedia article on Yuzu.

I moved my Yuzu from a pot to the ground in April of 2009 as an 18-inch tall tree.  The rootstock the Yuzu graft was attached to is Trifoliate Citrus. (Poncirus trifoliata, sometimes called Citrus trifoliata)  Why use a rootstock like Trifoliate Citrus?  Trifoliate Citrus does several good things for the tree:  it dwarfs the tree to a maximum height of 12 to 15 feet, it provides an additional few degrees of cold hardiness during the winter by forcing the tree to go into deep dormancy, and it protects against many kinds of root rot and soil-borne diseases that the Yuzu might be susceptible to if it were grown on its own roots.

My Yuzu really enjoys the North Carolina climate.  In less than four years it's grown to a height of nearly 10 feet and has produced an increasing number of fruits for my family each year.

     2008:  1 (while still in a pot!)
     2009:  0 (transplanted to the ground)
     2010:  2
     2011:  13
     2012:  42

My Yuzu tree just after transplanting in the ground, April 2009.

Yuzu, early spring of 2010

Yuzu, Summer 2011

My Yuzu tree now, September 2012

So what can you do with Yuzus?  They're too sour to eat like an orange, but the Japanese and Koreans are definitely onto something about the usefulness of the zest and juice.  Here's what my wife and I made with them last year:  Yuzu-Blueberry bread.

2 cups flour

1 cup sugar

1 tablespoon Yuzu zest

1 1/2 teaspoons baking powder

1 teaspoon salt

1/2 teaspoon baking soda

2 tablespoons canola oil

1/2 cup Yuzu juice

1/4 cup water

2 cups Blueberries (frozen are okay too)

1 egg

Icing:

1 cup confectioner's sugar

1-2 tablespoons Yuzu juice

Mix flour, sugar, salt, Yuzu zest, baking powder and baking soda together.  Add egg, Yuzu juice, water and oil, then combine.  Fold in the blueberries.

Pour into a greased bread pan and bake for 55-60 minutes at 350 degrees F, then cool on a rack.

Combine confectioner's sugar and Yuzu juice until smooth, drizzle over cooled bread.  

Harvesting the Yuzus.  In North Carolina the middle of October's a good time

Zesting the Yuzus.  If you've ever used Lemon or other Citrus zest you know now good this is.

Yuzu fruit cut open.  The seeds can either be discarded, or if you're ambitious, allowed to dry and then planted.  Don't store the seeds even slightly moist as they'll almost certainly be destroyed by mold.

Yuzu juice!  It's practically juice concentrate already with a powerful taste vaguely similar to a lemon/lime mix but not as "bright."  I don't have the culinary vocabulary to really describe it more than that.

Mixing  flour, sugar, baking powder, baking soda and salt with yuzu juice and zest.  Enlist the help of any nearby children.

  

Mixing in Blueberries last.  These were frozen since our Blueberries ripen in July and early August, well before the Yuzus.

  

Ready to go in the oven.

The finished and very yummy product: Yuzu-Blueberry bread!  These two flavors work really well together.

Since we're going to have so many more Yuzu fruit to experiment with this year I want to create Yuzu sorbet and perhaps Yuzu ice cream too.  There are some Korean hot tea ideas utilizing Yuzu and sugar that sound interesting as well.