Archive | December 2014

Mistletoe: friend or foe?

In 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’v 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.

Bob Polomski (C) 2014


Keep your cut Christmas tree alive during the holiday season

When it comes to Christmas trees, there’s nothing like the real thing.  In fact about 25 – 30 million Christmas trees are sold in the U.S. every year.  When you bring a live tree into your dwelling during the holiday season-yes, a cut Christmas tree is very much alive despite being severed from its roots-you need to keep its tissues hydrated, which affects it longevity.  Over time water is lost through the needles.  Eastern red cedar and Atlantic white cedar dry out rapidly, while Fraser fir and noble fir lose water much more slowly.

Water can be replaced via the cut end of the trunk.  To facilitate this make a fresh cut an inch from the end of the trunk before you put your tree in a water-filled tree stand.  Experiments with additives such as floral preservatives, sugar, and 7-Up® have shown to provide no benefit over pure water, but the tree stand must never be allowed to dry out.

How long a cut tree survives depends on the freshness of the tree when purchased, and how long it is kept moist. A friend of mine from New Hampshire kept his cut balsam fir in a cool room with ample water long after the holidays.  In fact, it actually put out several inches of fresh needles in early March.  It may seem unusual for my friend to keep a Christmas tree for that length of time, but it makes sense for someone who never takes down his Christmas decorations.

Bob Polomski 2014 (c)

Selecting and caring for live holiday trees

If 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.

Bob Polomski (c) 2014

Houseplants and winter blues

It’s tough being a houseplant during the winter, especially during the holiday season. Besides reduced light levels and low humidity, you have to give up your favorite spot near the window to seasonal plants like poinsettias, Christmas cactus, and amaryllis. If that’s not enough, you’re often faced with a caregiver who’s intent on watering you like a holiday plant: too often and too much.

The result of this treatment often causes houseplants to meet the Fate of most of their holiday kin: the top of the compost heap.

To avoid the Fate of recycling your houseplants, you may have to make a few adjustments to their indoor accommodations. Because the winter sun is lower and farther to the south, plants receive fewer hours of less intense light. So, houseplants that were exposed to low light on the north side of the house can be moved to east-facing windows. Plants near east-facing windows can be exposed to more sunlight by moving them to a south-facing window. Plants that were located on stands away from direct sunlight can be moved closer to a less exposed window to give them more light. In dimly lit rooms, rotate the plants every week or so.

Low moisture levels in the home during the winter can be uncomfortable to us and harmful to some houseplants. Relative humidity levels of 10 or 15 percent indoors can be tolerated by cactuses and succulents like snake plant (Sansevieria), cast-iron plant (Aspidistra), and various dracenas. Most others need a relative humidity of 40 to 60 percent. When exposed to these low moisture levels during the winter months, the leaves of most plants lose water faster than their roots can absorb it. As a result, the leaves curl, their tips turn brown, and flowering plants may drop their flower buds or flowers may wither up prematurely.

Move sensitive plants to cooler locations or to rooms that tend to be more humid than others such as the bathroom, kitchen (away from the oven), or a well-lit basement.

You can boost local humidity levels in the following ways:

  1. Water lost by leaves and potting mix raises moistens the air of its neighbors.
  2. Using a room humidifier or cool-mist vaporizer. Track humidity levels with a digital hygrometer so you can increase levels that will match your comfort, too. The ideal moisture level for people is between 30 percent and 50 percent relative humidity.
  3. Setting pans of water on radiators or wood stoves.
  4. Placing high humidity lovers on a pebble-filled tray of water inside an aquarium tank with an adjustable opening at the top. A small fan will improve air circulation and a heating cable under the tray will speed up evaporation.

One final tip regarding winter houseplant care is to avoid overwatering: the biggest cause of plant death during the winter months. Water according to the needs of the plant. Plants that are resting should be watered sparingly. Keep flowering plants moderately moist and watered when the surface of the medium feels dry.

Winter and the holidays can be a challenging time of year for both plants and people alike. However, by offering our houseguests a little attention now will help them realize the destiny we prescribed for them: to brighten our homes with their presence…next Spring.

Bob Polomski (c) 2014

Arbor Day: A Celebration of Giving Trees

Arbor Day 2014 Clemson University

Clemson University celebrated Arbor Day with a “Memorial Tree Plant Dedication” hosted by the Student Government Sustainability Committee. A Cherokee Princess flowering dogwood was planted in memory of the following Clemson University students who passed away this year: Kenneth Davis, Virginia Gilliam, Tucker Hipps, Andrew O’Neill, and Kendall Wernet.

“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.

National Arbor Day, founded by J. Sterling Morton in 1872, was April 25 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 is today, Dec. 4. 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, “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.”

Bob Pololmski  2014 (c)