Transcript Invasive Horticultural Species

Invasive Horticultural Species
This presentation covers a few of the many
invasive horticultural species in the United
States. The emphasis of the slides reflects
their original use for CA and AZ.
Author: Richard W. Hoenisch
WPDN Training and Education
[email protected]
Ailanthus altissima
Tree of Heaven
Native to China and introduced into California in the 1850s
as a shade tree, as an important Chinese medicinal plant,
and as a food plant for a species of silkworm. It was first introduced
to Europe (France and England) by a French Jesuit priest returning
from Nanking in 1751 for the manufacture of lacquer. It was introduced
into the eastern US from Europe in 1784 as an ornamental.
Tree of Heaven
Spreading by Suckers
J. M. DiTomaso
Tree of Heaven
Seed Production
© 2005 Luigi Rignanese
© 1995 Saint Mary's College of California
Tree of Heaven
Propagation and Spread
 Spread by seed and by creeping
roots
 325,000 + seeds per tree
 Seeds last about 1 year
 Seeds need 40 days of moisture
to germinate
 Dioecious – male and female
plants
Tree of Heaven
Seedlings
© 2005 Luigi Riganese
Crimson Fountain Grass
J. M. DiTomaso
J. M. DiTomaso
Crimson Fountain Grass reproduces from seed. Individual plants
can live for 20 years or more. Seeds can last up to 6 years in the
soil. Population increases in density after a burn.
Pennisetum setaceum
Crimson Fountain Grass
 Originally native to Africa and the Middle East, fountain
grass has been introduced to many areas, including Arizona,
California, Florida, Hawaii, Fiji, South Africa, and Australia. It
has spread in large part because of its popularity as an
ornamental plant. It is easily dispersed by vehicles, humans,
livestock, and, over short distances, by wind, by water, and
possibly by birds.
 The remarkable spread of this species into a broad range of
habitats in Hawaii is attributed to its ability to adapt. Hawaii
is the perfect habitat.
Crimson Fountain Grass
Crimson Fountain Grass
J. M. DiTomaso
Cultivars such as Rubrum, Cupreum, and Eaton Canyon
do not produce viable seeds
Buffel Grass
Pennisetum ciliare
Introduced into AZ at Tucson as a forage grass
in the 1930s with planting trials with the Soil Conservation
Service between 1938 – 1952
Began to get out of control around 1984
Reproduces by seed, rhizomes, and stolons
Out competes native plants
A serious fire hazard
Photo courtesy of the Arizona-Sonora Desert Museum
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Invasive Tamarisk Species
Saltcedar –
Tamarix ramosissima
Chinese Tamarisk –
Tamarix chinensis
Athel Tamarisk –
Tamarix aphylla
Smallflower Tamarisk –
Tamarix parvifolia
J. M. DiTomaso
Saltcedar in flower.
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Tamarix ramosissima
Saltcedar, Late Tamarisk
Native to eastern Asia, it has an
extensive root system with
a high evapo-transpiration
rate in arid climates. Block
waterways & out-competes
native vegetation. When
dry becomes a serious
fire hazard.
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Mr. & Mrs. Robert G. Young. USDA NRCS
Tamarix chinensis
T. chinensis has naturalized over wide regions and is an invasive. It
naturalizes aggressively and is a voracious consumer of water
It is notoriously dangerous in fires because its resinous leaves burn explosively
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Tamarix aphylla
Athel Tamarisk, Athel Tree, Flowering Cypress
Athel Tamarisk is widely planted as an ornamental,
especially in the South West, and is less invasive
than the other species. Native to northern Africa,
the Middle East, and India
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Tamarix parviflora
Smallflower Tamarisk, Early Tamarisk
A native of SE Europe, it is very invasive with very deep roots
that can access deep soil moisture, drying up wetlands. Roots
extract salts from deep under ground and excrete them
through the leaves, thus raising the surrounding salinity.
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Tamarisk Identification
J. M. DiTomaso
T. parviflora
J. M. DiTomaso
Tamarix ramosissima
T. chinensis
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Tamarisk Identification
J. M. DiTomaso
Foliage of athel tamarisk, T. aphylla, and saltcedar, T. ramosissima
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Tamarisk Propagation
J. M. DiTomaso
Jose Hernandez
T. ramosissima seedlings
T. ramosissima seed
J. M. DiTomaso
J. M. DiTomaso
T. parviflora resprouting from stem fragment.
T. ramosissima new saplings along creek19bed