DATE:    12/2/99
WRITERS: Bob Polomski, (864) 656-2604
         Dr. Don Ham, (864) 656-2480
EDITOR:  Giles Singleton, (864) 656-3876

Getting Rid of Mistletoe

     CLEMSON --  For the past few weeks I've answered a flurry of
calls from residents wondering what those green clumps are in the
nooks and crannies of their trees. Typically, mistletoe goes
unnoticed until the leaves have fallen from the trees. The other
popular question is: "How can I get rid of it?"
     Mistletoe is a pest that can affect the growth and vigor of
its host and 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.
     Basically, mistletoe is half-parasitic: it 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 like robins, thrushes, and cedar
waxwings.
     Within six weeks after being deposited by a bird on twigs
and small branches, the seed germinates. 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 five years for mistletoe to flower, which
occurs in the fall. Yellowish-green male and female flowers are
borne on separate plants. After pollination by wind or insects,
the female flowers give rise to berries that ripen in the winter
to begin the cycle again.
     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 interrupt flowering or cause the shoots to
fall off, but the mistletoe eventually resprouts and needs to be
treated again.
     The only effective way of ridding your tree of a mistletoe
infestation is pruning. However, care must be taken to avoid
overpruning. This can damage the tree.
     In general, 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 remember a tree 
can die from haphazard cuts.
     Trying to prune out a heavy infestation of mistletoe can be
more harmful than the mistletoe itself. -- Bob Polomski, Clemson
Extension consumer horticulturist and Don Ham, Extension urban
forestry specialist.
     For more information on urban tree care, check out
http://depts.clemson.edu/extfor/programs/urban_tree_care/.
                   **************************
     CORRECTION, please note: The web site for Clemson
Extension's "Making Wreaths" is:
http://virtual.clemson.edu/groups/psapublishing/Pages/Hort/EC696.pdf . 
     If you have questions or comments on gardening-related
issues, write to PSA Media Relations, Box 340129, A-101 Poole
Agricultural Center, Clemson University, Clemson, S. C. 29634-0129.
     You might also want to look for other "Buds and Blooms"
columns under 1999 News Releases at: www.clemson.edu/psamedia. 
                              END