Download Corymbia and Eucalyptus Trees Found in South Florida

Corymbia and Eucalyptus Trees
Found in South Florida
Stephen H. Brown
Lee County Extension Service
Fort Myers, Florida
Contents
Introduction
Corymbia torelliana
Eucalyptus camaldulensis
Eucalyptus deglupta
Eucalyptus grandis
Eucalyptus robusta
Eucalyptus rudis
References
Introduction
Eucalyptus is largely an Australian genus that consist of approximately 500-600 species of trees and
shrubs. They represent the majority of the forest trees that dominate the woodlands of the island continent. There are a few species that naturally occur on islands north of Australia. New Guinea and Timor
have representatives, and one, rainbow eucalyptus (Eucalyptus deglupta), extends to the Celebes and the
Philippines. This is the limit of their natural occurrence. The many trees found in California and the
Mediterranean region are the result of trees introduced from Australia.
In South Florida, only a handful of eucalyptus species can be found. This publication identifies one
corymbia and five eucalyptus species likely to be seen in South Florida. Corymbia torelliana is included
in this fact sheet as it is often mistaken for an eucalyptus and was formerly classified under that genus.
The University of Florida/IFAS Assessment of non-native plants in South Florida’s natural areas list C.
torelliana, Eucalyptus camaldulensis, E. deglupta, E. grandis and E. robusta as invasive species. These
trees are not recommended for landscape use in South Florida. In southwest Florida, C. corymbia and E.
grandis are probably the two species seen more often. E. deglupta and C. corymbia are the principal
trees of southeast Florida.
Eucalyptus trees are divided horticulturally into several groups. The ‘gum’ type is the most common of
the groups found in South Florida. The entire trunk, or all but a short portion of the base, eventually becomes smooth. Gum trees shed their bark in various patterns and secrete gum (known commercially as
kino), which seals the wounds after the bark peels away.
The features which are used to distinguish eucalyptus species include the form or shape of the tree, its
bark, foliage, flowers, fruit, and seeds. Form, or growth habit, varies significantly within a single species. Even among trees of the same size, there are marked differences in form and bark exfoliation on
the trunk and limbs.
The leaves of young trees, and regrowth on older trees after an injury, may look quite different from the
leaves on mature trees. The former are know as juvenile leaves. They are frequently broader and more
ovate than the leaves on older trees. The leaves on juvenile specimens are sometimes used for species
identification.
Corymbia torelliana
Synonyms (discarded names): Eucalyptus torelliana
Common Names: Cadaga Eucalyptus
Distribution: Native to Queensland, Australia.
Growth Habit: This is a large evergreen tree that can grow up to 100 feet tall in South Florida. Leaf
stems are usually covered with reddish or white hairs. In South Florida, Cadaga forms a light to dense
canopy shade tree. It has a recognizable pyramidal shape as a juvenile and develops an irregular crown
as an adult. There are few crossing branches.
Trunk and Bark: The bark is deciduous with the trunk and major branches becoming smooth, often
with a greenish pattern. Some gray to black bark may remain at the base of the trunk.
Leaves: leaves are alternate, ovate, and usually between 7 and 8.5 inches long and 3 inches wide with a
1 inch petiole. The leaf blade margin is wavy, its base rounded and the apex acute. It is green above and
lighter green beneath. The entire leaf, including the petiole, has coarse, irritating hairs which are most
prominent on the undersides.
Flowers: Flowers are staminous and are arranged in several showy terminal panicles. Panicles are usually 5 to 7 inches long. Individual flowers are approximately 2 inches wide and an inch long. A few
flowers may open in December but generally flower buds persist on the tree for several months before
becoming a showy display sometime in late March or April.
Fruit: The fruit are woody globose capsules about 0.5 inches in diameter, with 3 compartments. They
contain many very small seeds.
Comments: Cadaga is sometimes planted as a windbreak along farms, groves and housing developments. It is listed as invasive on IFAS assessment of non-native plants. It is not recommended for landscape use.
Early December.
Trees as windbreak. Early April
Cadaga Eucalyptus
A tree replete with flower buds in mid December but
will not have substantial bloom until April.
The same tree in full bloom in mid April.
Bark, Trunks and Branches
A tree with a 2.2 ft. diameter trunk.
This tree is approximately 80 ft. tall
with a 4.0 ft. trunk diameter.
Cadaga Eucalyptus
Bark, Trunks and Branches
Completely exfoliated trunk and branches.
Leaves
Hairy new leaf growth. Late October.
Alternating leaves. Late November.
Cadaga Eucalyptus
Flowers
A cluster of terminal immature panicles. Late November.
Flowers and flower buds. Early December.
Several panicles in early April.
Several panicles held by hand in early April.
Fruit
Newly formed capsule in late January.
Old capsules from the previous season.
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Eucalyptus camaldulensis
Synonyms (discarded names): Eucalyptus camaldulensis var. obtusa, E. longirostris, E. rostrata, E.
rostratus
Common Names: Red Gum, Murray Red Gum, River Red Gum, Blue Gum
Distribution: Native to Australia including New South Wales, Northern Territory, Queensland, South
Australia, Western Australia and Victoria. It is probably the most widely planted eucalyptus in the
world.
Growth Habit: Red gum often displays considerably morphological variation. It is a fast growing tree
80 to 110 feet tall. The tree divides into several large, upright branches supporting a more often airy
than dense crown.
Trunk and Bark: The trunk is short and massive, often 4-9 feet thick in very old specimen. The bark
exfoliate to reveal a smooth trunk that appear white, gray or pinkish red. However, some trunks retain
patches of gray scaly bark at their base. The upper trunk and branches are consistently smooth.
Leaves: Leaves alternate, evergreen and simple. Juvenile leaf blades are ovate to broad-lanceolate, dull
gray-green to green. Adult leaf blades are grayish green, linear to lanceolate, and curving towards the
tip. They are commonly from 5 to 9 inches long and 0.75 to 1 inches wide.
Flowers: Flower buds are ovoid and beaked, to 0.45 inches wide and 0.2 inches long. Staminous flowers
are white, inconspicuous and appear on new growth. Flowers can produce first grade honey. They usually begin appearing sparingly in Mid-December .
Fruit: Fruit are globular and small, to 0.25 inches wide and 0.4 long, and arranged in clusters.
Comments: A somewhat commonly seen eucalyptus in South Florida. This tree is too large for most
homes and is not a good shade tree. Its problems may include root rot, crown gall, and leaf spot diseases.
Scales and mites can be problematic. Red gum is listed as invasive on UF/IFAS assessment of nonnative plants.
This tree is approximately 90 ft. tall with a trunk diameter of 5.3 ft. Early October.
Mid March.
Red Gum Eucalyptus
Early November.
Bark, Trunks and Branches
This red gum has a trunk diameter, of 5.3 ft. and
is approximately 90 ft. tall.
Three red gum trees all about 70 ft. tall.. Mid April..
Red Gum Eucalyptus
Bark, Trunks and Branches
Branches with almost completely exfoliated bark.
Branches with almost completely exfoliated bark.
Red Gum Eucalyptus
Leaves
Leaves and flower buds in early
November.
Alternating lanceolate leaves.
Two leaves, one curved another
linear.
Flowers
Flower buds arranged in umbels,
early October
Early March.
Umbel inflorescences in late December.
Early March.
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Eucalyptus deglupta
Synonyms (discarded names): Eucalyptus multiflora, E. naudiniana, E. schlecteri
Common Names: Rainbow Eucalyptus, Mindanao Gum, Deglupta
Distribution: Native to Tropical Asia - Indonesia, Papua New Guinea, Philippines
Growth Habit: Rainbow eucalyptus is one of the fastest growing tree known. In South Florida, juvenile
trees grow about 6 feet a year, slowing down as they age, to a maximum height of about 100 feet. It is an
evergreen tree. Young trees have a pyramidal crown that becomes increasingly irregular with age. The
twigs are square in cross section.
Trunk and Bark: The trunk is mast-like, sometime buttressed. The bark peels off in narrow ribbons to
reveal the smooth inner bright green surface. When exposed to the air it gradually changes to blue, then
purple and finally yellow or brick-red. These combinations create a brightly multicolored trunk.
Leaves: The evergreen leaves are unusually shaped for a eucalyptus. The blades are oval, dark green,
glossy with a prominent midrib. They are typically 6.5 inches long to 2.5 inches wide. Petioles are about
0.4 inches long and the leaves are mostly opposite with a few near opposite arrangements. The leaves do
not produce the aromatic oils well know to other Eucalyptus.
Flowers: Flower buds are ovoid and the flowers are staminous, showy, and creamy white. They are
small, and borne in profusion in terminal or axillary umbels.
Fruit: Fruit are globular with pointed tip.
Comments: Rainbow Eucalyptus is perhaps the most widely planted eucalyptus tree in South Florida. A
very fast grower, it can quickly dominate a landscape. Wood is used for timber and pulp, veneer, plywood, particle board, hardboard, as well as firewood. Rainbow Eucalyptus is listed as invasive on UF/
IFAS assessment of non-native plants.
Juvenile tree with pyramidal form. Mid January.
Adult tree with an irregular form. Early November.
Rainbow Eucalyptus
Bark and Trunks
A slightly buttressed trunk.
A smooth trunk with completely exfoliated bark.
A smooth trunk with completely exfoliated bark.
Exfoliated leader and branches with an array of colors.
Rainbow Eucalyptus
Leaves
Oppositely arranged leaves in all three cases.
Flowers
Late November.
Flowers being pollinated by bees. Mid January.
Terminal inflorescences. Late December.
Flowering umbel. Mid January.
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Eucalyptus grandis
Synonyms (discarded names): Eucalyptus saligna var. pallidivalis
Common Names: Rose gum, flooded gum, saligna gum, scrub gum
Distribution: Native to north coast of New South Wales and south-central Queensland, Australia. Rose
gum is found in the moist subtropical lowlands with deep well-drained and fertile soils. It is often distributed on the margin of east flowing streams to the north of the Myall Lakes district.
Growth Habit: This is a fast growing medium to large sized tree up to 100 feet tall and a trunk diameter
of 4 feet in South Florida. Growth of 9 feet per year has been recorded under natural conditions. In plantation cultivation, it has a long shaft-like trunk, but when grown in open areas, branches may be only a
few feet above the ground. In old age, the trunk might be slightly bulbous.
Bark: Rough flaky bark is retained to varying degree at the base of the trees. Above the lower trunk, the
rough bark mostly gives way to a smooth white or pale blue-gray leader and branches. With age, more
of the bark on the lower trunk falls away to reveal a bark free trunk.
Leaves: Leaves are alternate, simple, and entire. The blades are often slightly curved and somewhat
wavy with a prominent midrib and distinct apex. The shapes can be quite variable; ovate, broad lanceolate to lanceolate. Ovate leaves are typically 5.75 inches by 2 inches. Lanceolate leaves are about 8.25
inches by 1.25 inches. The petioles in either case are approximately 0.75 inches long.
Flowers: Staminous flowers are borne in axillary umbels. The filaments are white and the anthers
cream. They are about 0.75 inches wide and high.
Fruit: Small pyriform capsules are up to 0.3 inches long and are borne in close clusters.
Comments: Rose gum is probably the most widely planted industrial eucalyptus because of its ease of
care, excellent form, rapid growth and variety of uses. In South Florida, this is likely the source of eucalyptus mulch purchased from garden centers. There are significant commercial productions for the
purpose of mulch in the area around Palmdale. Outside the United States, the wood is especially used for
boat building, flooring, plywood, paneling and general construction. The tree will tolerate below freezing temperatures. Rose gum is listed as invasive species on UF/IFAS assessment of non-native plants
and is not recommended for landscape use.
A tree approximately 45 ft. tall with a 21 inch trunk
diameter. Early December.
This tree is approximately 65 ft. tall. Early March.
Rose Gum Eucalyptus
A rose gum tree approximately 40 ft. tall with
a trunk diameter of 1.2 ft.
Bark, Branches and Trunks
Leader and branches are practically bark free.
This tree is approximately 60 ft. tall with a trunk diameter of
2.75 ft.
Rose Gum Eucalyptus
Bark, Branches and Trunks
This trunk, mostly covered with flaky bark, has a
trunk diameter of 1.75ft.
This trunk, free of flaking bark, has a trunk diameter
of 2.3 ft.
A trunk with significant loss of lower flaky bark.
An almost bark free 2.75 ft. diameter trunk
Rose Gum Eucalyptus
Leaves
Ovate, lanceolate and broad lanceolate leaves.
Typical lanceolate leaf shape. Early March.
Leaves with retentive capsules. Late November.
Rose Gum Eucalyptus
Flowers
Flowering umbels and flower buds.
Flowers in hand.
Fruit
Newly formed capsules. Early April.
Year old capsules.
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Eucalyptus robusta
Synonyms (discarded names): Eucalyptus multiflora,
Common Names: Swamp mahogany, Eucalipto,
Distribution: Native to the coastal plain of New South Wales and southern Queensland of Australia,
this tree has been introduced to many tropical and subtropical areas including the Caribbean, Florida,
Mexico and south to Argentina and Brazil. Also introduced to Hawaii and northern Africa where it is
commonly planted.
Growth Habit: Swamp mahogany is a fast growing tree up to 100 feet in height and 3.5 feet in trunk
diameter. Twigs are yellowish green and angled when young, becoming round and reddish brown. It has
a vase shaped branch pattern, the top of which may be easily broken by strong winds.
Trunk and Bark: Swamp mahogany usually grows with a single trunk, however, some elder trees may
exhibit a fusion of main trunk and suckers growing in close proximity. In South Florida, it is the only
eucalyptus of significance without exfoliating bark. The bark on the trunk and main branches are fibrous. Most trees have rough, deeply furrowed bark while others have somewhat flaky bark. Bark color
range from mahogany-red to gray.
Leaves: The simple alternate leaves are ovate-lanceolate, usually 6-8 inches long and 2 inches wide. The
petiole is thick and angular about 1 inch long. Blades are entire with many fine, widely spreading parallel lateral veins and are dark green on upper surface and only slightly paler beneath.
Flowers: Staminous flowers are borne in axillary umbels of about 8, with short, thick pedicels. The filaments are white, anthers are cream. The tree flowers from late summer to early spring, and the flowers
are not long lasting.
Fruit: The fruit are narrowly campanulate capsules to 0.5 inches long, extremely ribbed, the 3 valves
embedded deeply within. The capsules remain on the tree for some time after emergence. The tree sporadically flowers and fruits from late summer to early spring.
Comments: Swamp mahogany is listed as invasive on UF/IFAS assessment of non-native plants.
A partially flowering tree. Early October.
A tree approximately 80 ft. tall with a trunk diameter of
3.2 ft. Mid October.
Swamp Mahogany
Mid October.
Early November.
Swamp Mahogany
Bark, Trunks and Branches
Flaky, scaly bark on a 2.4 ft. diameter trunk.
Rough, furrowed bark on a tree with a trunk
diameter of 3.2 ft.
Swamp mahogany with a rough, furrowed bark.
The furrowed bark is retained throughout the entire length
and width of the tree.
Swamp Mahogany
Bark, Trunks and Branches
Retention of scaly, rough bark.
Retention of deeply furrowed bark.
Swamp Mahogany
Leaves
Ovate-lanceolate leaves with prominent
midribs.
Simple and alternating leaves.
Flowers
Inflorescences in full bloom. Early October.
Staminous flowers. Note the yellowish green angled young twig
on which they are produced.
Swamp Mahogany
Fruit
The fruit.
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Eucalyptus rudis
Synonyms (discarded names): None found
Common Names: Desert Gum, Flooded Gum, Swamp Gum
Distribution: Native to Western Australia. It occurs on the strip of coastal Western Australia south of
Geraldton to the vicinity of Bunbury and extends inland for 60 to 80 miles.
Growth Habit: Desert gum grows about 90 feet tall with a trunk diameter of up to 6 feet on a tree measured in Fort Myers.
Trunk and Bark: Short, stout trunk with rough dark gray bark and with the upper branches smooth and
gray.
Leaves: Leaves are alternate, simple, and entire. The shapes can be quite variable; ovate, broad lanceolate to lanceolate, straight or with a slight curve. However, lanceolate leaves predominate. Ovate leaves
are typically 3.0 inches long by 1.5 inches wide, and the lanceolate leaves are about 6.25 inches long by
1 inch wide. The petioles are about 1 inch long. Insect galls are often seen on leaves and stems.
Flowers and Fruits: The buds and fruits are difficult to distinguish from those of river red gum (E.
camaldulensis), but usually the rim of the fruit of flooded gum is shorter and flatter than those of river
red gum;. Fruits of flooded gum are about as wide as long, usually about 0.4 inches. The buds are larger
with a bluntly conic operculum.
Comments: This species is rarely seen in South Florida. Its resistance to frost is moderate, but is
unlikely to survive heavy or consistent frost. The name rudis mean ‘rough, unused, or raw’, and may
apply to the basal, rough bark, or perhaps to the timber which is mostly suitable for fuel.
A desert gum eucalyptus approximately 60 ft. tall
with a trunk diameter of 4.2 ft. Mid February.
A tree approximately 70 ft. tall with a trunk diameter of
6.0 ft. Early February.
Desert Gum Eucalyptus
Bark, Trunks and Branches
A tree approximately 80 ft. tall with a trunk diameter
of 6.0 ft.
Complete and partially exfoliated trunk and branches.
A tree approximately 70 ft. tall with a trunk diameter
of 4.2 ft.
Desert Gum Eucalyptus
Leaves
Leaf shapes vary greatly.
More typically, leaves are lanceolate.
Fruit
Newly formed capsules in early March.
Newly formed capsules in early March.
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References
Broschat, K. and A. Meerow. 2001. Betrock’s Reference Guide to Florida Landscape Plants. Betrock
Information Systems, Inc., Davie, Florida
Chippendale, G.M. and R.D. Johnston. 1983. Eucalyptus. Koon Wah Printing, Singapore
French, L. 1989. Gardening, Eucalyptus deglupta. Los Angeles Times, Los Angeles, California
Llamas, K.A. 2003. Tropical Flowering Plants: A Guide to Identification and Cultivation. Timber Press,
Portland, Oregon
Rockwood, D.L. and G.F. Peter. 2011. Cir 1194. Eucalyptus and Corymbia Species for Pulpwood,
Mulchwood, Energywood, Windbreaks, and/or Phytoremediation. UF/IFAS, Gainesville, Florida
Staples, G.W. and D.R. Herbst. 2005. A Tropical Garden Floria: Plants cultivated in the Hawaiian Islands and other tropical places. Bishop Museum Press, Honolulu, Hawaii
Florida Native Tree Fact Sheets
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This fact sheet was reviewed Peggy Cruz, Lee County Extension; Pat Rooney and Connie Brennon,
Master Gardeners.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, religion, age, disability,
sex, sexual orientation, martial status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension
Service, University of Florida, IFAS, Florida A. & M. 4/2014