Why doesn’t my _____________________ bloom?

This is mid-season for Springtime flowers because my wife’s allergies tell her so. She wonders aloud why plants have to bloom with such gusto. Alternatively, there are those who ask the age-old question: “Why don’t my plants bloom?”

Has it ever flowered? How long has it been in the landscape? Is this the first year that it hasn’t bloomed? Has the floral display declined over the years?

Answers to my questions are clues that often enable the gardener to determine “what-dunit.” If a plant has never bloomed, the cause could be related to the age or maturity of the plant, climate, soils, light, or something else. You need to determine which one is missing or limiting and correct it. Let’s take a look at a few of these factors that may need to be corrected. By the way, more detailed information can be found in the Clemson Extension Home & Garden Information fact sheet titled “Why Plants Fail to Flower or Fruit” (HGIC 2361).

1. Plant maturity. Some trees do not flower until they reach a certain age. Seedling dogwoods generally do not flower until they are seven years old. Seed-grown southern magnolias may take 10 or 12 years before blooming.

2. Climate. Cold temperatures often kill flower buds while posing no harm to vegetative buds, leaves, and stems. Our temperature fluctuations in winter and spring plays havoc with our plants, especially our past winter’s bouts with the “polar vortex.” When a plant breaks dormancy and starts growing in response to warm temperatures, it is more susceptible to injury when an uninvited cold air mass suddenly rolls in.

3. Soils. inadequate soil preparation or overly wet or dry soils affect flowering. Could the soil pH was be too acidic or is a nutrient lacking or unavailable? Overfertilizing with nitrogen will keep newly planted shrubs and trees in the business of making lots of leaves at the expense of flowers.

4. Light. Inadequate light may prevent flower bud-set. If a plant had never flowered, it was probably planted in shade that was too dense at the start. If it used to flower, surrounding plants or new structures may have reduced sunlight to prevent it from flowering.

I hope this helps those readers who want to experience that rush of euphoria when their shrubs and trees burst into bloom. For those who wish that it would all go away—the flowers as well as the itchy eyes, runny noses, and scratchy throats–I share your pain. Or at least my wife does.

 

What to do with those holiday plants?

Now that the holiday season is behind us and we’ve begun a New Year, I once again contemplate the fate of my holiday plants. The decision to save or compost rests solely on my shoulders. The Christmas tree gets ground up and recycled into mulch. I remove the withered flowers of the amaryllises and keep them well-watered and well-fed in bright light prior to moving them outdoors.  After the last spring frost in April, I plant them in “amaryllis alley:–a well-drained, full sun (morning sun and afternoon shade is fine) bed occupied by many other amaryllises from Christmas’ past.  I plant each bulb so the “neck” is 2 to 4 inches below the ground.  Then I blanket the transplanted bulbs with a 2 to 3 inch layer of mulch.

The Christmas cactuses stay in my home.  These tropical rain forest cactuses are commonly passed down from one generation to another as living keepsakes-a true testament to their durability and longevity as houseplants.  If you recently purchased a Christmas cactus, repot it in a well-drained potting mix comprised of equal parts of soil, peat moss, and perlite.  Keep your cactus in a window receiving bright, indirect sunlight.  This light exposure resembles their native habitat in the jungles of Brazil, where they reside in the shaded nooks and crannies of tree branches.  You can take them outdoors during the summer, but avoid direct sunlight, which can damage their leaves.

After they finish flowering, allow the top half-inch of water to dry out before watering your Christmas cactuses.  When new stem growth begins in the spring, water them when the soil surface feels dry.

Christmas cactuses need no coaxing to flower during the holidays.  After 6 to 8 weeks of short days (12 hours or less of daylight) and cool nighttime temperatures below 65 degrees, flowers buds will naturally appear.

When it comes to poinsettias, I ask myself every year:  should I attempt to reflower them for next Christmas or should I compost them?  I not only have to contend with my own poinsettias, but those of friends and acquaintances who can’t bear to toss them out.  As a horticulturist, they assume that I’ll find a good home for them.

I’ve attempted to reflower poinsettias in the past to bloom at Christmas, but the experience caused much marital strife as I attempted to meet their exacting requirements for bright daylight, 14 uninterrupted hours of darkness at night, and temperatures between 60 and 70 degrees.  My painstaking efforts resulted in Charlie Brown-looking poinsettias-at least, that’s what my wife called the survivors.

I can’t bear to compost poinsettias, so I go through my annual ritual of planting these Mexican natives in my “Poinsettia Patch” in April after the last spring frost.  The people who entrusted the care of their poinsettias to me have already forgotten about them-which is good because by June, I also forget about them.  It’s got to be Christmas magic, because every spring, there’s always room for more castoff poinsettias in my “Patch.”

9 Degrees F

This morning I woke up to a house with no heat and no running water. My mind was on the lack of these essentials that Americans like me take for granted; however, I also thought about the marginally cold hardy plants in my landscape. After hopping onto the tropicalissimo band wagon and experiencing the elation of now living in zone 8a instead of 7b, I planted a bunch of plants that are well-suited for the Lowcountry and Coast rather than the Piedmont.  I’m now experiencing Mother Nature’s wrath. Various cultivars of citrus, olive, figs, and Viente Cohol banana could have been injured or killed by these freezing temperatures despite my attempts at enveloping these them in burlapped cocoons of leaves and wheat straw.

I’m also reminded that the USDA map is based on “average annual minimum temperatures.” Plants don’t recognize averages. I can only hope that these cold temperatures also proved to be disastrous for the fire ants—squatters in my landscape who refuse to move.

Living Christmas trees make good landscape investments

MistletoeIf you’re planning on buying a live tree and expect to plant it outdoors after Christmas, choose the right tree.  Arizona cypress, deodar cedar, red cedar, and Leyland cypress are just a few of several double-duty “Christmas” trees that can be enjoyed in our homes over the holidays before being planted outside in the landscape.

When you shop for your tree, choose one with a firm root ball.  Store the tree in a protected location before bringing it inside.

Once you bring the tree indoors, keep it inside for as short a time as possible: no more than 10 days but 5 to 7 days would be better.  Keep the tree away from heating vents, fireplaces, and other heat sources.

Place the rootball in a large tub and water from the top.  Check the rootball daily and water often enough to keep the soil moist.

After the holiday, plant your tree immediately. The root ball will be very heavy so enlist the help of any holiday guests to help you carry it outside.

Plant it in a sunny well-drained location with plenty of room to spread out.

Dig the hole at least twice the diameter of the root ball and as deep.  Place the tree in the hole, stand it straight and fill in with soil.  Water thoroughly and mulch with 2 to 4 inches of compost, shredded bark, or pine straw.   Keep it well-watered during the winter months to help your tree become established.  This spring, stand back and watch your investment grow.

For further information, see “Living Christmas Trees“, HGIC 1751.

‘Tis the season for mistletoe

MistletoeIn last Sunday’s paper the following ad caught my eye:  “Real, Fragrant Mistletoe Shipped Direct To You From the Mountains of Oregon.”  I looked at the festive sprig of green leaves and pearly white berries secured with a bright red bow and smiled.  I’ve got plenty of mistletoe right outside my front door, thank you.  Now that the oaks have shed their leaves, I can see green azalea-sized clusters of mistletoes (Phoradendron serotinum) nestled comfortably in the bare branches.

It’s interesting how this native parasitic plant comes into its own during the holiday season.  For whatever the reasons, it has remained in our culture for centuries.

The modern tradition of using mistletoe around the Christmas holiday season dates back to the Celts of northern Europe.  Druids, the holy men of Celtic society, used mistletoe in winter solstice ceremonies.  Fearing the cold, short days of winter, the Druids used this green symbol of growth to ensure the return of the sun’s warmth in the spring.

Some cultures associated mistletoe with fertility because of its ability to bear fruit in winter.  The Ainu of Japan chopped-up mistletoe leaves and sprinkled them on their fields to ensure a good crop.  In Austria, a sprig of mistletoe was placed in a couple’s bed to encourage conception.

Of more modern origin is the act of kissing under the mistletoe on Christmas Eve.  It probably drew upon age-old rituals and traditions involving druidism and fertility rites.  In any event, it began as a fad in England and Wales in the 18th century and has become a Christmas tradition in many households today.

As a horticulturist, I’m intrigued by this half-parasitic plant.  Mistletoe has leaves to produce its own food, but steals water and nutrients from its host.  Mistletoe begins its life as a small white berry that is eaten and spread by birds, such as robins, thrushes, and cedar waxwings.  The seed germinates within 6 weeks after being deposited by a bird on twigs and small branches.  It produces “roots” that tunnel through the bark and tap the inner tissues for water and nutrients.  Shortly thereafter, the seedling produces shoots and leaves.  It takes about 5 years for mistletoe to flower, which occurs in the fall.  Yellowish-green male and female flowers are borne on separate plants.  After being pollinated by wind or insects, the female flowers give rise to berries that ripen in the winter to begin the cycle again.

For the past few weeks I’ve answered a flurry of calls from residents wanting to know if those green clumps will harm their trees and how they can be removed.

Mistletoe is a pest that can affect the growth and vigor of its host, and can expose the tree to attacks by diseases and insects.  In some instances, mistletoe can cause branches to die back, and heavy, shrubby mistletoes can break entire limbs.  In other situations, mistletoe is simply a cosmetic problem, which only affects the appearance of the tree.

The only effective way of ridding your tree of a mistletoe infestation is by pruning.  Cut the infected limb one to two feet below the plant because mistletoe “roots” may extend up to a foot on either side of the point of attachment.  Breaking off the tops, similar to plucking off the leaves of dandelions or wild garlic in the lawn, only encourages regrowth.  Obviously, pruning out mistletoe clumps from the uppermost reaches of trees should be left in the hands of certified arborists.  If you’re a do-it-yourselfer, please avoid butchering the tree with haphazard cuts.

Since the 1950s, scientists have been searching for cheaper and more effective methods of controlling mistletoe.  Herbicides have been evaluated, but they may pose a threat to the host.  Growth hormone sprays, such as ethephon (Florel® Brand Fruit Eliminator), interrupt flowering or cause the shoots to fall off, but the mistletoe eventually resprouts and needs to be treated again.

If you decorate your home with store-bought or home-grown mistletoe, hang it up high out of the reach of children and pets.  The berries are toxic and the sap may irritate the skin of some people.  Watch out…it also can turn Scrooges into smoochers.

Living cut Christmas trees

I received this question sometime ago, and I thought it was very insightful: “When a Christmas (Fraser fir) tree is cut down, is it still alive and why or why not? Also if it is still alive, how long can it live separated from the root ball?”

A cut Christmas tree is still alive after it has been severed from its roots.  The tree has a finite amount of water in its tissues that is lost over time via transpiration from the needles.  Christmas trees have a variable post-harvest shelf-life, which depends on the species.  Eastern red cedar and Atlantic white cedar dry out very quickly, but Fraser fir and noble fir have a much slower drying time.

When a cut tree is rehydrated, it will absorb about 1 qt of water per day per inch of stem diameter.  Water enters the tree from the cut end and is lost from the needles.  To facilitate rehydration remove a 1/2 to 1 inch section from the base before putting the tree in a water-filled stand.  The cut should be perpendicular to the trunk.  Researchers have found that plain, unadulterated water is best.  L. E. Hinesley and S. M. Blankenship, reported in HortTechnology (Oct/Dec 1991, 90-91; Effect of water additives on Fraser fir needle retention,) that water alone was better than the commercial floral and tree preservatives they evaluated as well as bleach (sodium hypochlorite), aspirin, sugar, and 7-Up®.

Arbor Day: A Celebration of Giving Trees

Grich_Liveoak_3

Live oak planted on Arbor Day in memory of Stephen Gregory Grich, a junior electrical engineering student at Clemson University (1989-2012).

Once there was a tree and she loved a little boy” is the first sentence in the children’s book:  The Giving Tree.  This story chronicles the lifelong relationship between a boy and a tree. From boyhood to his golden years, this tree selflessly gives all that it has to the boy: leaves, shade, a place to hide, and so on. (I won’t spoil the ending for you.)  Each time I read this story by Shel Silverstein, I’m reminded of Arbor Day, a day that emphasizes the importance of trees in our lives.

I first learned of The Giving Tree many Arbor Days ago when I was 12.  Since then, I’ve read the story hundreds of times and celebrated many Arbor Days in many states.  Most often these one-day tree-planting ceremonies were accompanied by speeches, poems, and songs acknowledging the importance of trees.

National Arbor Day, founded by J. Sterling Morton in 1872, is always the last Friday in April. South Carolina has been celebrating Arbor Day since 1934. It falls on the first Friday of December, which was Dec. 6 this year. It falls on the first Friday of December, which happens to be an ideal time of year for planting shrubs and trees. Although the top-growth goes dormant, the roots of newly planted shrubs and trees continue to grow throughout the winter months as long as the soil temperature remains above 45 degrees F. So, when spring arrives, the fall-planted shrubs and trees will have produced an extensive root system that will Grich_Liveoak_2sustain them throughout the stressful months of summer.

This Arbor Day at Clemson University we conducted a ceremonial planting of a live oak (Quercus virginiana), which was planted in memory of Steven Gregory Grich, a junior electrical engineering student at Clemson (1989-2012). In front of the Strom Thurmond, family members, friends, and visitors gathered to place a marble headstone in remembrance of Grich, a junior electrical engineering student at Clemson.

Although Arbor Day may only be celebrated once or twice a year, you don’t have to recognize the benefits of trees just twice a year.  Daily I am reminded of the importance of trees in our lives.

Around our homes trees surround us with the seasonal beauty of their leaves and flowers, and their attractive bark and branch architecture.  They offer privacy and hide unsightly views.  Trees and shrubs provide food, shelter, and nesting for wildlife.  Pollen and nectar for hummingbirds, butterflies, and bees are additional bonuses.  Their roots keep soil in place and increase water movement into soil to reduce surface runoff from storms.

Trees save energy and money.  The shade provided by deciduous trees planted on the southeastern and western sides of your home can reduce indoor temperatures by 8 to 10 degrees in the summer and reduce air conditioning costs up to 30 percent.  In the winter, their leafless branches allow the sun to warm our homes.

When trees are used as a windbreak on the north side of a home to intercept cold winter winds, they can save from 10 to 50 percent in heating costs.

Trees in our towns and cities enliven our downtown areas.  They hide harsh scenery and soften the hard outlines of masonry, metal, and glass.  Trees absorb carbon dioxide and in return replenish the environment with oxygen.  According to the SC Forestry Commission, “trees absorb enough carbon dioxide over a year’s time to equal the amount you produce when you drive your car 26,000 miles.”

Like the boy in The Giving Tree, we depend on trees and cannot live without them.  If you have existing trees, maintain them properly so  your living investments will grow in value with each passing year. Consider planting a tree to give your neighborhood and community a living legacy. This simple, selfless act offers a multitude of benefits to all of us. It also says a lot about you. According to an English proverb: “He who plants a tree loves others besides himself.”

National Arbor Day, founded by J. Sterling Morton in 1872, is April 29 this year, always the last Friday in April.  South Carolina has been celebrating Arbor Day since 1934. It falls on the first Friday of December, which was Dec. 6 this year.

On Arbor Day a live oak was planted in memory of Steven Gregory Grich, a junior electrical engineering student at Clemson. Family members and friends of Steven Gregory Grich and friends gathered at 11 a.m. on campus Friday to place a marble headstone in remembrance of Grich, a junior electrical engineering student at Clemson.

Arbor Day at the national and state level encourages us to plant and care for trees.

I first learned of The Giving Tree many Arbor Days ago when I was 12. Since then, I’ve read the story hundreds of times and celebrated many Arbor Days in many states. Most often these one-day tree-planting ceremonies were accompanied by speeches, poems, and songs acknowledging the importance of trees.

So although Arbor Day may only be celebrated once or twice a year, you don’t have to recognize the benefits of trees just twice a year.  Daily I am reminded of the importance of trees in our lives.

Around our homes trees surround us with the seasonal beauty of their leaves and flowers, and their attractive bark and branch architecture. They offer privacy and hide unsightly views. Trees and shrubs provide food, shelter, and nesting for wildlife. Pollen and nectar for hummingbirds, butterflies, and bees are additional bonuses. Their roots keep soil in place and increase water movement into soil to reduce surface runoff from storms.

Trees save energy and money. The shade provided by deciduous trees planted on the southeastern and western sides of your home can reduce indoor temperatures by 8 to 10 degrees in the summer and reduce air conditioning costs up to 30 percent. In the winter, their leafless branches allow the sun to warm our homes.

When trees are used as a windbreak on the north side of a home to intercept cold winter winds, they can save from 10 to 50 percent in heating costs.

Trees in our towns and cities enliven our downtown areas.  I could not imagine Main Street without its comforting canopies of green.  Trees hide harsh scenery and soften the hard outlines of masonry, metal, and glass. Trees absorb carbon dioxide and in return replenish the environment with oxygen. According to the S.C. Forestry Commission (www.state.sc.us/forest/urban.htm), “trees absorb enough carbon dioxide over a year’s time to equal the amount you produce when you drive your car 26,000 miles.”

Like the boy in The Giving Tree, we depend on trees and cannot live without them.  If you have existing trees, maintain them properly so  your living investments will grow in value with each passing year.  Consider planting a tree to give your neighborhood and community a living legacy.  This simple, selfless act offers a multitude of benefits to all of us. It also says a lot about you. According to an English proverb: “He who plants a tree loves others besides himself.”