Plant List 3 - Aggie Horticulture - Texas A&M University

Woody Ornamental Plants
HORT 306 Fall 2012
Plant List 3
Trees and Shrubs for West Texas
& the Southwestern U.S.
Southwestern Flavor
Reading Assignments
In Landscape Plants For Texas And Environs,
Third Ed.
– Family descriptions for:
• Acanthaceae
Acanthaceae, , Anacardiaceae,
Berberidaceae,
Bignoniaceae
Bignoniaceae, ,
Caprifoliaceae
Caprifoliaceae, , Cupressaceae
Cupressaceae, , Ericaceae Ericaceae, , Fabaceae Fabaceae, , Fagaceae Fagaceae, ,
Malvaceae
Malvaceae, , Pinaceae,
Rosaceae,
Salicaceae,
Schrophulariaceae,
Sapindaceae
Sapindaceae, , Tamaricaceae,
Zygophyllaceae
– Descriptions for individual species
See page listings on Plant List 3 Handout
(also available under lists on course website)
Anisacanthus quadrifidus var. wrightii
Flame
Acanthus
• Irregular upright twiggy shrub, 3’ - 4’ tall
– Shoot hardy z. 8-9(10 9(10), ), roots to z. 7, Texas native
• At best open & airy, ratty ratty when when not not at its its best
– Prune severely in spring to encourage dense
growth; flowers on new wood
• Primary attraction = red red-orange orange to yellow-
orange slender trumpet trumpet-shaped shaped
flowers, spring to frost
– Attracts hummingbirds & butterflies
• Very site adaptable, heat, drought, salt,
and high pH soil tolerance, excellent
for naturalizing; needs good drainage
West Texas & Southwestern U.S.
http://planthardiness.ars.usda.gov/PHZMWeb/Images/300DPI/SIMP_US_lower48_fullzones_300dpi.jpg
Overlaps in
north with
Intermountain
West & West
Coast plants,
in east with
semi-arid Hill
Country and
Southern
Plains flora
A few Texas cities in El Paso, Fort Stockton, Alpine, San
Angelo – plus other locations in Mohave, Sonoran, and
Chihuahuan deserts like Phoenix, Tucson, Albuquerque, Las
Cruces, Reno, Palm Springs, Palm Desert and Las Vegas.
Berberis Berberis trifoliolata
Agarito
• Medium, 3’ - 5’, evergreen shrubs, USDA z. 7 (?) - 10
– Leaflets reminiscent of holly (Ilex lex) ) leaves green to blue blue-green green
– Stiff upright branches, irregular rounded mound
• More heat, drought, & high pH soil tolerant than most
Berberis spp spp.
• Tolerant of cotton root rot

Berberis trifoliolata Agarito
• Spiny leaves are maintenance liability
• Grow on well drained soils only
• Accent, barrier plant, naturalizing,
xeriscapes
xeriscapes, , hedges, low screen
Fallugia paradoxa
Apache Plume
• Tolerant of reflected heat, drought, high pH soils
• Avoid wet or poorly drained soils soils, , or high relative
humidity; cold tolerance varies with provenance;
best treated as subshrub
• Mostly deciduous to semi-evergreen
semi evergreen
woody shrub in USDA z. 9 -11 11, , subshrub
or herbaceous herbaceous perennial perennial in z. z 8(7b) 8 (7b)
• Foliage is open at best, ratty if not
periodically pruned, 1’ to 33’
’ (5’) ( 5’) tall
• Pink hibiscus hibiscus-like like flowers are best feature
• Tolerates much heat and drought, some
salts; requires well drained soils & sun
• Xeriscapes
Xeriscapes, , naturalizing, southwestern
landscapes, informal perennial and mixed
borders, perhaps rock gardens
Eysenhardtia texana
Texas Kidneywood
• A fine textured open canopy
deciduous shrub, 6’ to 8’ (15’) tall
• USDA zones 7 - 10
• Scraggly in the wild, denser under
cultivation
• Small white to creamy white
fragrant flowers in 1” - 4” racemes
• Heat, H d drought, h and d high hi h pH H soil il
tolerant
• Naturalizing, xeriscapes
xeriscapes, , mixed
border, good bee tree
Pavonia lasiopetala
Rockrose
Fallugia paradoxa
Apache Plume
• Medium size irregularly
rounded shrub with semi-
evergreen fine textured
dark green foliage
• USDA z. 33-10
10 with proper
provenance selection
• Solitary single 1” rose rose-like like
flowers, peak in spring,
sporadically to frost
• Achenes with filamentous
feathery persistent styles,
white white-tan tan flushed pink or
purple, showy
Larrea tridentata
Creosote Bush
• One of the most widespread shrubs in the native flora
of West Texas and SW USA, hardy USDA z. 8 (7) ( 7) to 11
• Irregular broadly mounded small to medium
evergreen shrub shrub, , aromatic foliage
• Interesting small yellow flowers and fuzzy fruit

•• Extremely Extremely drought drought,
heat, and wind tolerant
• Difficult to transplant,
use small container
grown plants, intolerant
of poor drainage
• Will accept shearing
Larrea tridentata
Creosote Bush
Leucophyllum candidum
Violet Silverleaf
• Silver white foliage and violet flowers
• Smaller more compact plant than L. frutescens
• Intolerant of poor drainage, high humidity, use
i in semi-arid semi i arid id t to arid id portions ti of f USDA z. 7 - 11
Leucophyllum
frutescens
Texas Sage
• Small to medium evergreen native Texas shrub
– Green to superior silver silver-gray gray foliage, 4’ - 8’ tall tall
– T Tendency d to t open l leggy / / scraggly l h habit bit if if not t pruned d
• Attractive bell bell-shaped shaped pink pink-purple purple to white flowers
– Peak bloom in spring, summer flushes after rain events
Image courtesy of Dr. Wayne Mackay
• An outstanding small
evergreen tree for West Texas
• Four season appeal
– Clusters of white Pieris Pieris-like like
spring flowers
– 2” - 3” clusters of red berries,
late summer - early winter
– Attractive broad-leaved
broad leaved
evergreen foliage
– Exfoliating white, tan, orange,
apricot to red brown bark
Arbutus xalapensis
Texas Madrone
Leucophyllum frutescens
Texas Sage
• Extreme heat & drought
tolerance, takes high pH soils
• Intolerant of poor drainage, avoid
high g relative humidity y regions g
• Good xeriscape plant, hardy in
USDA zones 8 (7) - 11
• Tolerates heat,
drought, high
pH soils
• Hardy USDA
z. 7b (7a) - 10
• Intolerant of poor drainage and
high relative humidity
• Slow to establish in landscape,
difficult to transplant
Shorn as formal hedge
Arbutus xalapensis
Texas Madrone

Acacia greggii
Catclaw Acacia
• Small tree / large shrub, 20’ - 30’ tall, hardy z.7 - 10
• Creamy white flowers, numerous vicious thorns
• Acacias can be limbed up or sheared sheared, barrier plants
Prosopis glandulosa
Honey Mesquite
• Irregular spreading deciduous rounded crown
• One of most widely distributed trees in Texas
• Several desirable ornamental features;
– Ferny fine textured foliage, filtered shade, fruit and flowers
can be attractive, adapted to almost any site
• Small, 15 15’ - 20’, 20 20’, , deciduous deciduous or
semi semi-evergreen evergreen tree
• South Texas tree naturalized
further north
• Several interesting features;
bright green trunk, fine textured
leaf, filtered shade, yellow flowers
• Relatively short-lived, short lived, cold hardy
only to z. 8b (8a) - 11
• Problems:
– Thorns can rival those
of Gleditsia triacanthos
– Takes over pasture land
– Difficult to transplant
– Allergenic pollen
– Looks rough in winter
Parkinsonia aculeata
Retama
Prosopis
glandulosa
Honey
Mesquite
Parkinsonia aculeata
Retama
• Thorns maintenance liability, can be
weedy
• Very site adaptable, cold &
excessively wet soils are limiting,
drought, heat, salt & alkaline soils OK
Chilopsis linearis
Desert Willow
• Small, 15’ - 20’, deciduous tree, USDA z. 7 (6b?) - 10
– Irregular rounded crown, single or multi multi-trunk, trunk, brittle
– Open canopy, filtered shade, movement in breezes
• Catalpa Catalpa-like like flowers in small terminal panicles
– Heavy bloom in spring, sporadic individual flowers and
lesser flushes following rain events through mid mid-fall fall
– White, light pink to maroon pink, bicolors, musky scent

Chilopsis linearis
Desert Willow
• Rapid grower; limestone soil,
salt, heat, drought tolerant, but
intolerant of poorly drained soils
• Super patio or accent tree,
picturesque, but messy capsules
Cercis canadensis var. texensis
Texas Redbud
• Smaller, Smaller, more drought and
alkaline soil tolerant than
C. canadensis canadensis var.
canadensis
• Smaller dark glossy green
leaves with with more undulate
margins than than on C.
canadensis var. canadensis
• Round crown open deciduous
tree, 15’ - 25’
• Bright yellow 1” powderpuff
powderpuff-like like
flowers, spring g to frost
• Very drought and heat tolerant,
hardy in USDA zones 7 - 10
• Casts filtered shade
• Brittle wood subject to
wind / ice / snow damage
• Good small tree for West Texas
and arid regions; slow to
establish, hat-rack hat rack appearance
when young
Leucaena retusa
Goldenball Leadtree
Cercis canadensis var. mexicana
Mexican Redbud
• Even smaller, more drought,
and alkaline soil tolerant than
C. canadensis var. texensis
• Even smaller, more glossy, and
undulate margins than on
C. canadensis var. texensis
Cercis
canadensis var.
Cercis canadensis
Three Varieties of Redbud
Hybrid
swarm
texensis Cercis
canadensis
var.
canadensis
Cercis
canadensis var.
mexicana
Courtesy Rowman & Littlefield Publ. Group; redrawn from originals by Benny J. Simpson
Rhus glabra
Smooth Sumac
• Small moderately coarse
textured tree / large shrub
• Foliage in umbrella-
shaped crown, 10’ - 15’
tall
• O Outstanding di red d f fall ll color l
even in warm temperate
regions, panicles of red
drupes on female plants
• Tends to form colonies
from suckers, hardy in
USDA z. 4 (3) -9 • Any sunny site not
permanently wet
• Can be weedy
Naturalizing, bank
stabilization,
highway plantings,
wildlife food

Rhus lanceolata
Prairie Flameleaf Sumac
• More refined than R. glabra
• Excellent fall color
• Bit less suckering than
R. glabra, but it still
can b be weedy d in i
manicured settings
• Tolerant of heat, drought,
& limestone soils
• A Texas native, probably
useful in USDA z. 66-9
• Somewhat short short-lived, lived,
needs well drained soils
Sophora secundiflora
Texas Mountain Laurel
• Medium / large evergreen shrub / small tree
• Sun to part shade, requires good drainage,
z. 8 - 10, Texas native, best on alkaline soils
Sambucus mexicana
Mexican Elder
• Small picturesque semi-
evergreen tree, 15’-20’ 15’ 20’
• Picturesque thick contorted
stems, spreading rounded
crown, resembles big bonsai
plant
• Creamy white late winter to
early summer flower clusters
• Tends to grow late in
autumn; poor fall acclimation
can result in cold damage in
USDA z. 8; short-lived; short lived; can
become weedy; brittle wood
• Intolerant of poor drainage,
but needs water
Ungnadia speciosa
Mexican
Buckeye
• Large deciduous multi multi-trunk trunk
shrub / small tree, 10’ - 12’ (30’)
– Not a true Buckeye ( (Aesculus Aesculus
spp spp.), .), called buckeye due to
resemblance of seed to
Aesculus spp.,
poisonous fruit
• Interesting spring pink to rose
flowers, overall effect resembles
that of Cercis canadensis
– Unfortunately may be
concurrent with foliage
emergence
Sophora secundiflora
Texas
Mountain
Laurel
• Dark glossy green foliage, racemes of
purple to pink pink-purple purple flowers, spring
– Strong fragrance, grape bubble bubble-gum gum scent
– Poisonous bright red seeds seeds, , used in crafts
• Texas native, excellent heat & drought
tolerance
– Requires moderately good drainage
• Good naturalizing plant, xeriscapes
xeriscapes, ,
shrub s ub borders bo de s
• Can be limbed up into small patio tree
• Often has good yellow fall color
Ungnadia speciosa
Mexican Buckeye

Vauquelinia
angustifolia
Chisos
Rosewood
Rosewood
• A medium shrub to small tree, 8’ to 12’
(20’) tall, hardy to USDA z. 7 – 9 ( (10) 10)
• Handsome dark glossy evergreen
leaves
• Fragrant cyme cyme-like like clusters of small
white flowers in late spring
• Wi Wind d flutters fl tt leaves l
• Extremely cold hardy, z. 2 – 9 (10)
• Numerous problems, many
common to most poplars;
– Messy (leaves, fruit, twigs),
weak wood, invasive roots,
cankers, root rots, drop leaves
in drought, weed problem
Populus deltoides
Eastern Cottonwood
Vauquelinia angustifolia
Chisos Rosewood
• Very heat, wind, & drought
tolerant, most any well drained
soil, good West TX & SW US
landscape shrub
• Fireblight can be serious in humid climates
• A medium size, 30’ to 50’,
evergreen tree useful in
USDA zones 8 - 11
• Initially a strongly upright,
becoming spreading and
rounded with time
• Very tolerant of heat and
drought, withstands some soil
salts and some alkalinity, very
handsome bark
• Needs well drained soils, may
have problems with excess
rainfall/high RH
• Source of commercial cork
Quercus suber
Cork Oak
• Large native deciduous tree
along stream/river courses
• Irregular upright oval to vase-
shaped crown composed of 3
or 4 main branches, very rapid
growth rate
• Coarse in leaf and winter
habit, picturesque in native
habitat, best left in large
naturalized planting sites,
60’ - 80’ tall common, 100’
possible
Populus deltoides
Eastern
Cottonwood
Cupressaceae Cypress Family
• A temperate to tropical gymnosperm family
– 15 to 21 genera containing 100 to 125 species
– Mostly trees, some shrubs, often resinous,
coniferous, and evergreen
– Scale Scale-like like to awl awl-like like leaves, often aromatic
• Monoecious or dioecious dioecious;
dioecious dioecious; ;
– Males tiny yellow yellow-brown brown cones at branch tips
– Females are persistent few few-valved valved woody cones or
hard berries with waxy coatings
• Important genera include: Calocedrus
Calocedrus, ,
Chamaecyparis
Chamaecyparis, , Cupressus
Cupressus, , Juniperus Juniperus, ,
Platycladus
Platycladus, , Thuja Thuja, , and Cupressocyparis

Cupressus
arizonica
Arizona Cypress
• Medium / large evergreen tree
• Attractive green to blue blue-green green foliage
• Interesting shreddy red-brown red brown bark
• Tolerant of hot, dry sites with alkaline
soils, hardy in USDA zones 7 (6b) - 11
• Avoid poorly drained sites,
susceptible to borers and spider mites
• Trunk cankers have been reported
Juniperus
scopulorum
Rocky Mountain
Juniper
• Essentially a western counterpart to J.
virginiana virginiana; ; intergrades in North Texas
• Native to to high high elevations elevations of of Texas
Texas
Panhandle, Guadalupe Mountains, and
Arizona
• Somewhat narrower crowned and of
smaller, 30 ‘ to 40’, stature than J.
virginiana
• Tolerates less heat [z. 3-7 7 (8)] ( 8)] and humidity
than J. virginiana virginiana, , but otherwise culture is
similar with good drought resistance
• Narrow cultivars, such as ‘Skyrocket’ are
popular in the trade
Image courtesy of Benny Simpson
Cupressus
sempervirens
Italian
Cypress
• Classic spire spire-like like silhouette, 30’ to 40’ tall
• Favorite for formal Mediterranean landscapes
• Alternative to Lombardy Poplar for SW USA
• Grows in most of our region, better adapted
to drier portions of USDA zones 8 (7b) to 11
• Avoid poorly drained soils and high RH
• Juniper blight, spider mites, trunk cankers
and root rots can be problems
Pinus eldarica
Afghan Pine
• Pyramidal needled evergreen
tree, 35’ 35’- 45’ (60’)
• Christmas tree tree-like like conical
growth form in youth, more
sculpted and picturesque
later in life
• Fine Fine-textured textured wiry look
• Cold hardy to USDA z. 6,
tolerant of z. 9 heat
Juniperus ashei
Ash Juniper
• Counterpart to J. virginiana in Hill
Country y and p parts of West Texas
• Small evergreen tree, 15’ to 20’ (25’)
• Important for wildlife; Golden
Check Warbler nesting sites
• Useful for similar purposes as J.
virginiana virginiana, , but on drier sites
• Needs well drained soils; drought
and heat tolerant; hardy z. 7 (6) – 9
• Ecological controversy; Pollen
Pinus eldarica
Afghan Pine
• Good drought, heat, salt, and high pH soil
tolerance, but intolerant of poor drainage
– One of few pines to provide soft Eastern White Pine
look in Central & West Texas,
widely adaptable
• Deserving of wider planting; tip moth problems?

Pinus cembroides
Pinyon Pine
• Group of taxa, small to medium trees,
20’ 20’- 30’, with 1 to 4 evergreen needle-like needle like leaves
– Sometimes separated into 5 species,
P. cembroides, P. remota, P. edulis,
P. monophylla, P. quadrifolia
• Dense tear-drop tear drop-shaped shaped trees, slow growers
• Need good drainage, heat, cold, drought, and
limestone soil tolerant
• Dark green to blue blue-green green foliage, important for
wildlife cover and food, edible seeds
Questions / Comments?
All material represented herein are
copyrighted by the author, or otherwise as
indicated, with all rights reserved.
For permission to reproduce text or
images from this presentation write:
Dr. Michael A. Arnold
Dept. of Horticultural Sciences
Texas A&M University
College Station, TX 77843 77843-2133 2133
email ma ma-arnold@tamu.edu
arnold@tamu.edu