Download Crape myrtle Lagerstroemia - Lake County Extension

Crape myrtle
Lagerstroemia
Propagation
Crape myrtle is usually propagated by softwood stem tip cuttings collected during the
warm season, using very tender wood with red or pink colored wood. Under intermittent
mist, the cuttings should root in 8-15 weeks.
Pests and Diseases
The current Insect Management Guide for Commercial Foliage and Woody Ornamentals
can be found at http://edis.ifas.ufl.edu/IG012. The current Professional Disease
Management Guide for Ornamental Plants can be found at http://edis.ifas.ufl.edu/PP123.
Crape myrtle aphid
Recognition: Crape myrtle aphids are 1/8 inch long, pear-shaped, pale yellow and have
two cornicles (or "tail-pipes"). The winged forms have
black markings on their wings. They are found mostly on
the undersides of the leaves. Aphids secrete honeydew on
which sooty mold grows prolifically, often the first
evidence that the aphids are present. Their feeding may
cause distortion of new growth.
Contributing factors: Crape myrtle aphids are host
specific, and appear each year in late spring, remaining
Sooty Mold
until the leaves drop in the fall. Powdery mildew resistant
varieties of crape myrtle appear to be highly susceptible to
the aphids.
Management
recommendations
: If the sooty mold
can be tolerated,
Crape Myrtle Aphid
the crape myrtle
aphid can be helpful in attracting many
Biological Control
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beneficial insects to the landscape. Insecticidal soaps, oils, or approved insecticides
may be used to control aphid populations if necessary.
Metallic beetles
Recognition: Small blue metallic beetles feed on leaf surfaces and edges.
Contributing factors: none
Management recommendations: Damage is usually
Metallic beetle
insignificant. Control is
damage
difficult due to the
mobility of the insect.
Metallic beetle
Powdery mildew (Oidium sp./Erysiphe lagerstroemiae)
Recognition: The fungus grows on the surface as a white powdery covering on
leaves, shoots and buds. The disease causes leaf curling and growth distortion.
Contributing factors: Powdery mildew is most active in the cool, dry periods
of spring and fall. It is most severe in shady locations.
Management recommendations: Resistant varieties are available. Use approved
fungicides when conditions favor disease development.
Culture
There are 56 species of crape myrtle native to woodlands and forests of India, China and
Southeast Asia. The commonly cultivated species are: Indica, Speciosa, Fauriei and
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Hybrids. Some species are logged commercially for timber in India and Malaysia, but are
threatened in Burma and Thailand from overlogging. Extracts from some species’ plant
parts reportedly have medicinal uses; extracts from L. speciosa can be found in over-thecounter supplements The most widely grown species of crape myrtle, indica, was
cultivated in ancient China and introduced to U.S. in the early 1800’s. Recently other
species have been introduced for their own characteristics and for hybridizing with
indica.
Lagerstroemia indica has many ornamental qualities including: grows as multi-stemmed
shrub or small tree, summer flowering, flower colors of purple, lavender, white, pink, and
rose-red. It is easy to grow in full sun and well-drained soil; pest resistant; tolerant of
drought, heat & humidity; tolerant of a wide range of soil pH; and easy to propagate by
cuttings (softwood, semi-hardwood, hardwood and root). Unfortunately, Lagerstroemia
indica has some limitations that gave breeders reasons to improve crape myrtle. It is
susceptibility to powdery mildew, “dead heading” needed for best re-bloom, and the size
availability was limited to large shrub or small tree. The introduction of new species and
the hybridization of these has produced cultivars with increased disease resistance and
variations in plant size and flower color among other characteristics.
Recommended Cultivars
Cultivars with unusual flower color
Prairie Lace
Candycane
Raspberry Sundae®
Splash of Pink
Petite Red Imp, Victor, Carolina Beauty, Dynamite®
Arapaho, Centennial Spirit, Christiana
Houston, World’s FairWatermelon Red
Lipan
Velma’s Royal Delight
Near East
Muskogee, Basham’s Party Pink
Caddo
Comanche, Tuscarora
Firebird, Pink Velour®
pink edged in white
pink edged in white
dark pink edged in white
mix of pink, white and
bicolor flowers
true red
deep red
watermelon red
reddish lavender
magenta purple
shell pink
lavender pink
bubble-gum pink
coral pink
hot pink
Dwarf Cultivars
These cultivars are less than 4 feet tall in 5 years and can be used as: a small
shrub/foundation plant, a groundcover (in masses), a woody/herbaceous perennial flower,
a container plant, or a hanging basket. These cultivars and their flower colors include:
Delta Blush pink
New Orleans purple
Pocomoke
rose
Houston
rose pink
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Semi-Dwarf Cultivars
These cultivars are 4 - 12 feet tall in 10 years and can be used as a large shrub or limbed
up to use as a “patio tree” or specimen plant. These cultivars and their flower colors
include:
Acoma
white
Caddo
bubble-gum pink
Hopi
pink
Tonto
red
Intermediate Cultivars
These cultivars are 12 - 20 feet tall in 10 years and can be used as small trees or large
shrubs. These cultivars and their flower colors include:
Osage
pink
Dynamite® true red
Sioux
pink
Pink Velour® burgundy foliage, hot pink flowers
Apalachee
lavender
Tree Cultivars
These cultivars grow over 20 feet tall in 10 years and can be used as small trees. These
are many widely-available cultivars. Some of the new cultivars in this size category are:
Biloxi
light pink
Choctaw
pink
Fantasy
white; red bark
Natchez
white
Sources
1. Knox, Gary W. 2003. (Extension pub.) ENH-52, Crape Myrtle in Florida
2. Neal, Cathy, Celeste White and Eleanor Foerste. Key Plant and Key Pests in Central
Florida Landscapes. University of Florida Extension slide set.
3. University of Florida Landscape Plant Propagation Information.
http://hort.ufl.edu/lppi/
4. U.S. National Arboretum, www.usna.usda.gov/Newintro/intro.html
Prepared by:
Juanita Popenoe, PhD, Extension Faculty, Regional Commercial Horticulture
Lake County Extension, 1951 Woodlea Rd., Tavares, FL 32778-4052
Tel.: (352) 343-4101, FAX: (352) 343-2767
June 2008
The Institute of Food and Agricultural Science (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and
other services only to individuals and institutions that function without regard to race, creed, color, religion, age, disability, sex, sexual orientation,
marital status, national origin, political opinions or affiliations. U.S. DEPARTMENT OF AGRICULTURE, COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF FLORIDA, IFAS, FLORIDA A. & M. UNIVERSITY COOPERATIVE EXTENSION PROGRAM, AND BOARDS OF COUNTY
COMMISSIONERS COOPERATING.
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WEEKLY IPM REPORTING FORM FOR CRAPE MYRTLE
Date:
County:
Site Code:
Scout:
Crape Myrtle Aphid
Beneficials present (check):
Plant #2:
Plant #3:
Plant #1:
Cultivar:
Cultivar:
Cultivar:
Leaf Aphid count
Leaf Aphid count
Leaf Aphid count
winged not winged No.
winged not winged No.
winged not winged
No.
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1
1
2
2
2
3
3
3
4
4
4
5
5
5
6
6
6
7
7
7
8
8
8
9
9
9
10
10
10
Total
Total
Total
% parasitized:
% parasitized:
% parasitized:
Damage:_________slight_________moderate_________severe
Scouting procedure for crape myrtle: Count aphids on 10 leaves
per plant. Pick leaves at random up and down the stem, using
several different stems per plant. If more than 50 aphids per leaf, it is
acceptable to count half a leaf then record double that amount.
Friendly fungus ___
PFR fungus
___
parasitic wasp ___
lady beetle adult ___
lady beetle larvae ___
praying mantid ___
syriphid fly larva ___
predatory mites ___
spiders
___
lacewing adult ___
lacewing larvae ___
wasps
___
tachinid fly ___
other:
Other pests/problems:
Insecticides applied:
product:
date:
Environmental Conditions:
Temperature range (days):
60-70° 70-80° 80-90° 90-100°
Temperature range (nights):
40-50° 50-60° 60-70° 70-80°
Irrigated
Unirrigated
Rainfall since last sampling
date: ____ inches
Note any extreme weather:
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