Because of the wide variation in size, shape, coloration and floral adornment, trees have a definite place in the planting plan and should be placed to best advantage. For roadway or line planting, plant only one species in the row, using group plants to secure variety in color and form. Certain types of trees make splendid background plants and groups of the tall growing forms can be used as points of emphasis to break the monotony, or hedge row effect, of line plantings and add grandeur to the horizon or silhouette view. If planted in the foreground of small properties, large trees tend to dwarf their surroundings and spoil landscape effects. If shade and comfort are the prime considerations, it may sometimes be desirable to sacrifice a point in landscape technique.
As a general rule, it seems highly desirable to give evergreen trees preference over forms which shed their leaves during the winter season. When referring to evergreens, we mean broadleaf evergreens and not conifers. It seems inappropriate to use conifers in a subtropical planting where there is such a wealth of available material producing more naturalistic effects and having more appeal to residents and visitors alike.
The most general use of this group of ornamentals is for shade. By massing the tree plantings toward the rear of the premises, it is usually possible to secure the much needed shade, and in addition, background effect for the landscaped home grounds. In some cases, it may be advisable to plant shade trees in borders along the property line. Of the more useful shade trees for the Lower Rio Grande Valley, we might call attention to the merits of such trees as Brazilian Silk Oak (Grevillea robusta), Texas Ebony (Pithecolobium flexicaule), Anaqua (Ehretia anacua), Anacahuita (Cordia Boisseri), Orchid Tree (Bauhinia sp.), Spanish Live Oak (Quercus virginiana), Tree Acacia (Acacia Wrightii), and Huisache (Acacia Farnesiana).
Municipalities and owners of large estates will be interested in trees for thin line, or avenue, planting. In this group we have subjects such as: Hardy Australian Pine (Casuarina lepidophloia), Brazilian Pepper (Schinus terebinthifolius), Retama (Parkinsonia aculeata), and Carob Tree (Ceratonia Siliqua).
To add color to roadside or border plantings of trees one might use groups or single specimens of Anacahuita, Huisache, Retama, Orchid Tree, Desert Willow (Chilopsis linearis), Bignonia Tree (Tabebuia species), and Coral Tree (Erythrina herbacea var. arborea).
Specimen trees should be used with care to add interest to the landscape scheme. Monkey puzzle (Araucaria imbricata), Sausage Tree (Kigelia pinnata), Calabash Tree (Crescentia species), Star Pine (Araucaria excelsa), Monkeypod or Rain Tree (Samanea Saman), Womans Tongue Tree (Albizzia Lebbek), Pickle Tree (Averrhoa carambola) and Banyan (Ficus benghalensis) are recommended for such use.
Acacia Baileyana. Robins Egg Blue Acacia. Both forms of this species are weak growing but very ornamental, the sprays of flowers being used in floral arrangements. A. Baileyana produces gray-green foliage and yellow globular flower clusters. A. Baileyana var. purpurea produces very small blue-green foliage tipped with purple. (Leguminosae)>
Acacia cultriformis. Knife, Crowded-Leaf Acacia. A tall shrub or small tree having very crowded, blue-green pinnate foliage; produces typical acacia flowers, yellow in color.
Acacia Farnesiana. Huisache. This native acacia produces very dark green, acacia foliage, deep golden-yellow balls of flowers very early in the spring, which are followed by short, cylindrical, black seed pods. A rapid growing, flowering ornamental, having many thorns.
Acacia Greggii. Long-Flowered Catsclaw. A small native tree which produces medium green acacia foliage and elongated heads of cream colored spikes of flowers. Very thorny.
Acacia longifolia var. floribunda. Flowering Acacia. A small tree which produces dark-green linear leaflets, and a profusion of creamy-yellow balls of flowers.
Acacia Roemeriana. Round-Flowered Catsclaw. A small native acacia tree which produces very dark green, oval leaflets and a profusion of greenish-yellow balls of flowers, followed by curved red seed pods. This is one of the first of the native trees to bloom in the spring.
Acacia Wrightii. Tree Acacia. A large growing, typical acacia tree which produces elongated heads of white acacia flowers. This is the largest of the native acacia trees.
This group of trees is usually grown for its ornamental bi-pinnate foliage and crowded spikes of spring flowers which are followed by dark colored pods.
Albizzia Julibrissin. Silk Tree, Powder-Puff Tree. A small, deciduous tree having finely cut, medium green foliage and gray bark. In the spring, it produces typical "powder puff" flower heads which are pale pink in color. A slow growing species. (Leguminosae).
Albizzia Lebbek. Womans Tongue Tree. An ornamental tree having bright green, pinnate foliage, inconspicuous heads of greenish flowers, and ornamental, flat seed pods about nine inches long. The clacking of these seed pods give the tree its name. The trees grow rapidly, and appear to be well adapted, but are tender to cold. It produced small white flower heads the second year after planting. Leaves are pinnate; flowers are in heads.
Amyris madrensis. Torchwood, Rue Plant. This native evergreen tree is one of the thornless members of the Rue Family. It is upright in habit of growth and produces dark green, crinkled, pinnate foliage; small white flower heads, and attractive reddish-brown drupe-like fruits. The entire plant has an aromatic odor. (Rutaceae).
Araucaria araucana (imbricata). Monkeypuzzle. A tall, pyramidal, evergreen tree with spreading, upward curved branches, small, dark green, stiff, lanceolate leaves, and large cones (five inches to eight inches).
Araucaria excelsa. Norfolk-Island Pine, Star Pine. A symmetrical, evergreen tree having its branches arranged in horizontal planes so as to form five pointed stars when viewed from above. One of our most interesting exotics. (Pinaceae).
Arbutus Unedo. Strawberry Tree. A low growing tree or shrub, which has dark green, oblong evergreen leaves with red stems. The white flowers are born in the fall, followed by scarlet berries. This tree is very slow growing, and has not proven very well adapted to conditions in this region. (Eriaceae).
Bauhinia. Orchid Tree. Large growing shrubs or trees which produce heart-shape leaves, and showing, orchid-like flowers. The White Flowered Orchid Tree, or Mountain Ebony, B. variegata var. candida (B. alba) appears to be the hardiest to cold damage, while the yellow variety, B. tomentosa (St. Thomas Tree), and the Red Flowered Orchid Tree (B. Galpini) appear to be quite tender to cold. The Purple Flowered (B. purpurea) and the Pink Flowered (B. triandra) Orchid Trees make rapid recovery if frozen back. (Leguminosae).
Bixa Orellana. Lipstick Tree, Annatto. A small tree producing ovate leaves, panicles of pink to rose flowers, and prickly tan capsules which contain seeds covered with a red coating that is the consistency of lipstick and can be used as a coloring agent. (Bixaceae).
Bumelia lanuginosa (angustifolia). Chittamwood. False Buckthorn. Small thorny trees or shrubs having short stiff branches terminating in thorns. The greenish white, small flower clusters are borne in profusion along the woody stems. Its fruits resemble small black cherries. It produces wedged shaped leaves one to three inches long, glossy green above and woolly underneath. (Sapotaceae).
Bumelia Schottii (spiniflora). Como, Ironwood. A small, round topped, native evergreen tree bearing numerous, shining, dark green, oval leaves. In late fall, it produces clusters of greenish flowers, which are followed by blue, oblong fruits in late spring. The Mexicans call the plant chicle, and obtain a latex substance by "bleeding" the green fruits.
Calliandra hemaetocephala. Caliandra. An evergreen tree which produces attractive, bright green, pinnate foliage. The globose flower heads produce long silky, purplish to red stamen. (Leguminosae).
Callistemon rigidus. Rigid Bottlebrush. This very dense, small tree has very dark green, linear leaves and extremely large, showy "brushes" that are produced in great profusion. (Myrtaceae).
Callistemon lanceolatus (citrinus). Lemon Bottlebrush, Weeping Bottlebrush. A type having bright green, lanceolate leaves and new growth tipped with rose. The young leaves contain a volatile oil that has the odor of lemon. The bushes are less showy than those of C. rigidus.
These large bushes or small trees appear to be well adapted to conditions in this region. Their chief ornamental value lies in the bright red "brushes" tipped with gold. These "brushes" are followed by hard, dry, seed capsules which adhere to the stems for several years. It takes two years for the seed to mature. The "brushes" are relished by orioles and other fruit eating species of birds.
Carica Papaya. Papaya. A herbaceous tree that is well adapted to conditions in this region and makes rapid growth. It produces large, palmate leaves, cream colored to yellow flowers and large, yellow, melon-like edible fruits. The plants are usually dioecious, and do not come true from seed, unless the flowers are hand pollinated. Papaya plants are quite susceptible to cotton root-rot disease, but treating the soil with sulfur (applied in holes about the tree) will help control the disease. Since papayas are very tender to cold, all plants should be well banked for winter; if the tops are frosted back, the plants can be topped off, and allowed to sprout out from below. (Caricaceae).
Carya (Hicoria) Pecan. Pecan growing has not proven successful as a commercial enterprise in this region, but a number of pecan trees are being used for shade. The native Texas rootstock has not proven well adapted, and other rootstocks are being tried. (Juglandaceae).
Cassia. Shower Trees. Six species of cassia trees are being grown at the Valley Experiment Station, all of which are well adapted, but some species are quite tender to cold. These small trees produce such a profusion of showy blooms that they deserve a place in the landscaping scheme.
Both C. nodosa ( Pink Shower) and C. grandis (Grand Shower) produce oval leaflets and numerous pink flowers. C. nodosa produces bright green glossy foliage; C. grandis produces reddish bronzy foliage.
The four yellow flowering cassias produce flowers that are similar, but the foliage and seed pods are distinctive. C. Fistula (Golden Shower) produces broad, dark green leaflets and long, slender, "sausage-like" pods (12" long). C. laevigata (Smooth Senna) also produces dark green, broad leaflets, but small, cylindrical pods about six inches long. C. splendida (Showy Senna), which has become established on this side of the Rio Grande, is native to the San Juan River Valley. It produces a low, spreading plant with bright green, large oval leaflets and cylindrical pods about six inches long. C. tomentosa (Woolly Senna) is also a native of the Mexican side of the Rio Grande, but has become established on the American side of the river. This is an upright tree having gray bark. It produces a continuous bloom of yellow flowers which has a few red markings at the base of the petals. The flattened pods are about six inches long. Unlike most of the cassias which bloom in the spring and summer, C. laevigata blooms in August. (Leguminosae).
Casuarina. The Casuarinas have proven to be rapid growing in this region but seem to be quite subject to root rot. Casuarina lepidophloia (Hardy Australian Pine) does not produce seed but multiplies from root sprouts. C. Cunninghamiana (Cunninham Beefwood) has also proven to be a well adapted species. They are pyramidal in habit of growth, are very symmetrical, and produce very dark green, pine-like foliage. C. equisetifolia (Horsetail Casuarina) has a greater salt tolerance, but the foliage is less dense, and the plants are more subject to cold damage and to root disease. C. glauca (Australian Pine) and C. montana (Australian Pine) produce the typical pine-like foliage and small cones, but must be considered less desirable than other species. (Casuarinaceae).
Cedrus Deodora. Deodor Cedar. A tall pyramidal tree producing graceful, sweeping branches and blue green, pine-like foliage. (Pinaceae).
Celtis laevigata. Southern Hackberry, Smooth-Leaf Hackberry. A native, deciduous tree having a spreading top. It grows rapidly, and the rapid propagation of the tree causes it to become a pest in many instances. It produces small, ovate, notched, leaves; inconspicuous flowers and small red berries. (Ulmaceae).
Ceratonia Siliqua. Carob, St. Johns Bread. A spreading evergreen tree having dark, reddish-brown bark, red stems, dark green obovate leaflets with a reddish tint, and racemes of red flowers which are followed by silique-like fruits about eight inches long which are said to be edible. This very ornamental tree is quite subject to root rot. (Leguminosae).
Cercidium macrum (floridum). Palo Verde, Short Leaf Retama. A small flowering tree having dark green bark, very small leaflets and few thorns. (Leguminosae).
Cercidium texanum. Texas Palo Verde, Thorny Palo Verde. Almost shrub like in appearance, this plant is easily identified by the greenish-yellow bark, and numerous thorns.
The showy yellow flowers of these native, evergreen trees are identical in appearance to those of the Retama, but the trees appear to be partially defoliated because of the sparcity of foliage.
Cercis canadensis. Redbud, Judas-Tree. A small, deciduous tree that produces dull green, heart-shaped leaves. In the early spring, before the leaves appear, the branches are covered by showy, rosy red, small flowers which never completely open. One of the first flowering trees to bloom in the spring. Not widely used in the Valley. (Leguminosae).
Chilopsis linearis. Desert Willow, Flowering Willow. This is a native evergreen tree having willow-like foliage, and lavender colored tubular flowers. (Bignoniaceae).
Chrysophyllum oliviforme. Star Apple, Satin Leaf. A small, compact evergreen tree that produces large, glossy, dark green oblong leaves which are coppery gold color underneath, giving the plant an unusual ornamental effect. (Sapotaceae).
Cinnamomum Camphora. Camphor Tree. An evergreen, pyramidal tree which produces dense, glossy, dark-green ovate leaves having an aromatic odor. The greenish-colored flowers are followed by a profusion of small, succulent, black berries. Well adapted. (Lauraceae).
Citrus mitis. Calamondin. A citrus tree which produces numerous small, oblong leaves and a continuous supply of small, fragrant, white flowers and small, orange colored, acid fruits. This is one of the most ornamental of the citrus species. (Rutaceae).
Condalia obovata. Brasil, Brazil Wood. This native evergreen tree or tall shrub is sometimes called "Bright Green Ebony." It produces very dense, small bright green, obovate leaves, numerous thorns, inconspicuous small flowers, and numerous small red berry-like fruits. (Rhamnaceae).
Cordia Boisseri. Anacahuita, Wild Olive. One of the most ornamental of the native trees. It is a round headed small tree which produces coarse large ovate leaves, and a continuous bloom of large white flower clusters followed by creamy white fruits about the size and shape of ripe olives. This tree, which is found in abundance in the Rio Grande Valley, attracts numerous birds and butterflies and should be included in every planting. Grows readily from seed. (Boraginaceae).
Cordia Sebestena. Geiger-Tree, Red Flowered Cordia. A rapid growing, evergreen tree having a round head, large, rough, ovate, green leaves; showy red flowers, followed by olive-shaped fruits. This tree appears to be fairly well adapted to conditions in this region.
Crescentia. Calabash Tree. Both species of Calabash appear to be well adapted to conditions in this region but are very tender to cold. The large fruited type (C. Cujete) produces "gourds" up to twelve inches in diameter; the smaller fruited type (C. alata) produces fruits from four to eight inches in diameter. The latter produces peculiar lanceolate leaves usually in groups of three, the middle leaf being trifoliate on the tip. (Bignoniaceae).
Cupressus arizonica var. bonita. Arizona Cypress. This blue-green pyramidal conifer is fairly well adapted to the Valley. (Pinaceae).
Cupressus lusitanica. Portuguese Cypress. This well adapted species has a semi-horizontal habit of growth and the dark-green foliage assumes a bluish hue during the winter season.
Cupressus sempervirens var. horizontalis. Horizontal Italian Cypress. These dark green conifers appear to be well adapted and have been used in the Valley to a limited extent.
Cupressus sempervirens var. stricta. Royal Italian Cypress (Columnar Cypress). These formal subjects are just as well adapted as the horizontal type, but should be used with discretion.
Cupressus tortulosa. Bhutan Cypress. This is a true Cypress, and the pyramidal trees have dark-green drooping foliage with a yellowish cast.
Daubentonia (Sesbania) Tripetii. Red Flowered Sesbania. A large shrub or tree from South America that appears to be semi-deciduous under conditions in this region. It has dark green, pinnate leaves and produces numerous racemes of showy, orange and red pea-like flowers followed by three lobed seed pods. (Leguminosae).
Delonix (Poinciana) regia. Royal Poinciana. A rapid growing evergreen tree that produces dark green, pinnate foliage; and in early summer, a profusion of large red and yellow flowering racemes that are followed by long seed pods. Royal Poinciana trees are quite tender to cold, and should be given protection until they are mature. It also has been observed that they are quite subject to attack by Huisache girdlers. (Leguminosae).
Diospyros Kaki. Japanese Persimmon. A round topped, deciduous tree having rather large, round, dark green, ovate leaves. The large, edible fruits are orange to red in color, and vary in shape from oblate to conical. (Ebenaceae).
Diospyros texanum. Texas Persimmon, Chapote, Possum Plum. A small native evergreen tree which produces dark green, glossy, oblong leaves 1 to 1-1/2 inches long. In the spring it produces a number of white, bell-shaped flowers which are followed by purple, plum-like fruits which are relished by the Mexican children.
Diospyros virginiana. Wild Persimmon. This deciduous tree bears small, bright ovate leaves, and small edible fruits of uncertain quality.
Persimmon trees are grown to a very limited extent in the Lower Rio Grande Valley. However, the cultivated form appears to be fairly well adapted, and the wild species makes rapid growth.
Dovyalis caffra. Kei Apple. A rapid growing, evergreen, thorny tree which produces bright green obovate leaves, greenish flowers, and bright yellow, juicy fruits. (Flacourtiaceae).
Ehretia anacua. Anaqua, Knock-Away. A native tree which produces a round head; thick, rough, dark-green elliptic leaves; and in the spring a profusion of small, fragrant white flowers which are followed by numerous small red to yellow edible fruits. Sometimes called Sugarberry. (Boraginaceae).
Eriobotrya japonica. Loquat. An evergreen, round-topped tree that produces large, rough, dull-green oblong leaves. The white flower clusters are borne throughout the summer and fall, but only the late fall flowers produce fruit, which ripens the following spring. The edible, plum-like fruits are orange in color. (Rosaceae).
Erythrina Cristi-galli. Brazilian Coral Tree. A slow growing deciduous tree which produces dark green, long-ovate trifoliate leaves and racemes of large, dark red, pea-shaped flowers followed by pods filled with red seed. (Leguminosae).
Erythrina herbacea. Annual Coral Tree, Firemans Hat. This is a peculiar native plant. It is an annual above ground but has a large perennial root. It produces flowers and foliage similar to E. herbacea var. arborea.
Erythrina herbacea var. arborea. Native Coral Tree. A small native tree found only along the Rio Grande Valley Coastal area. It produces bright green, three lobed, trifoliate leaves, and in late winer and early spring, produces numerous firecracker-like spikes of rosy-red, closed pea-shaped flowers, which are followed by bean-like pods that split open and expose the bright red seed. It is easily propagated by seed or cuttings.
Esenbeckia Runyonii. Esenbeckia. A small, round-headed, deciduous, native tree bearing trifoliate leaves. In the summer it produces showy panicles of cream colored flowers followed by brown capsules. (Rutaceae).
Eucalyptus algeriensis. Algerian Eucalyptus. This variety is the result of a cross between E. rostrata and E. viminilis and appears to be better adapted to Valley conditions than most species in this group. It produces blue-green lanceolate leaves. (Myrtaceae).
Eucalyptus globulus. Blue-Gum Eucalyptus. Magnificent specimen trees of this species, occasionally seen in the Valley, have tempted many persons to spend considerable sums in an attempt to grow these majestic trees, which appear to be rather exacting in their soil requirements. They are also somewhat tender to cold.
Eucalyptus rostrata. Red-Gum Eucalyptus, Creek Eucalyptus. This species appears to have a fairly wide range of adaptability and a larger percentage of the young trees become established than is the case with Blue-Gum and many other species.
Eucalyptus tereticornis. Gray-Gum Eucalyptus. A rapid growing species that is fully as well adapted as Red-Gum.
Eucalyptus viminalis. Manna-Gum Eucalyptus. A tall growing species having pendulus branches. Its leaves are narrower than the average Eucalyptus foliage.
Eugenia Jambos. Malabar-Plum Rose Apple. A small evergreen, spreading tree having bright green, shining, lanceolate leaves, the new growth being tinged with red. The greenish flowers, consisting mostly of stamens, appear in the spring, followed by small, yellowish fruits which have a rose odor and flavor. Very tender to cold. (Myrtaceae).
Ficus benghalensis. Banyan Tree. A large ornamental Ficus which produces shining, oval, dark green leaves, and numerous small crimson fruits. This tree is unusual in that it produces numerous aerial roots. (Moraceae).
Flacourtia indica. Governors Plum. A small tree or tall spreading shrub which is occasionally used where a tall hedge is needed. It produces glossy, evergreen, ovate leaves, and the edible fruits resemble cherries or small, red plums. Well adapted, but somewhat tender to cold. (Flacourtiaceae).
Fortunella crassifolia. Meiwa Kumquat. Small tree up to five feet high which produces small white flowers and olive-shaped fruits about three-fourths of an inch in diameter. (Rutaceae).
Fortunella japonica. Marumi Kumquat. Very small, bushy tree (3-4) which produces very small, white flowers, and small, round, orange colored fruits.
Fortunella margarita. Nagami Kumquat. The tallest of the Kumquat trees in the Experiment Station collection. It produces oblong fruits almost two inches long. The kumquats produce small, glossy, dark green, lanceolate leaves. They have considerable ornamental value.
Fraxinus Berlandierana. Mexican Ash, Rio Grande Ash. A native, rapid growing, deciduous shade tree. The bark of this species is not as white as that of the Arizona Ash. Rio Grande Ash leafs out earlier and holds its leaves later in the fall than does the Arizona Ash. (Oleaceae).
Fraxinus velutina. Velvet Ash, Arizona Ash. A rapid growing deciduous shade tree having light green foliage.
Two species of ash are grown in the Lower Rio Grande Valley, one of which is a native to this region. They produce deep green, compound leaves, and light green, dioecious, apetalous flowers which appear in early spring about the time trees begin to leaf out.
Ginkgo biloba. Maidenhair Tree. A tree having light green, lobed foliage somewhat resembling the Maidenhair Fern. It grows very slowly, and is not well adapted to conditions in this region. (Ginkgoaceae).
Grevillea robusta. Silk Oak. A tall, symmetrical, evergreen tree having dark green, pinnate foliage which is silvery on the under side. The racemes of flowers are rusty-red and are followed by seed capsultes. (Proteaceae).
Hibiscus tiliaceus (Paritium tiliaceum). Mahoe, Tree Hibiscus. A salt-resistant ornamental tree that produces large, leathery, rounded-cordate leaves and showy, yellow, hibiscus-like flowers. (Malvaceae).
Helietta parvifolia. Barretta. A small native tree belonging to the citrus family. It produces small, dark green trifoliate leaves, peculiar shaped creamy white flowers followed by small orange colored, aromatic fruits. The flowers are similar in appearance to those of Amyris madrensis. (Rutaceae).
Ilex sp. Native Holly. This native holly is an ornamental evergreen plant found growing in the old lake bed southwest of Mission. It has light-gray bark and dark green coriaceous leaves. In the fall it produces a profusion of small red berries. (Aquifoliaceae).
Jacaranda acutifolia (ovalifolia). Jacaranda. A flowering tree which produces fern-like, evergreen foliage in this region. In the summer, this tree produces a profusion of powder blue, tubular flowers which are followed by long brown capsules. The foliage is easily damaged by frost, but the tree leafs out again quite soon after being frozen. (Bignoniaceae).
Juniperus chinensis var. sylvestris. Chinese Juniper, Sylvester Juniper. Similar to Horizontal Italian Cypress in general appearance, but trees are smaller and foliage is lighter in color. (Pinaceae).
Juniperus excelsa stricta. Spiny Greek Juniper. A rather small, conical type having prickly, dark green foliage.
Juniperus lucayana. Southern Red Cedar, Gulf Coast Cedar. This low growing, evergreen tree produces needle-like foliage. It is recommended for use along the Gulf Coast because of its resistance to salt injury, and to high winds.
Juniperus Sabina. Savin Juniper. A very dwarf spreading type having bright green foliage.
Juniperus virginiana. Red Cedar. A symmetrical, tall growing cedar having very dark green foliage and horizontal branches.
Juniperus virginia glauca. Silver Juniper. This tall growing conifer has attractive blue-green foliage that has a silvery appearance at certain seasons. Very popular in the Valley.
Several species of junipers are very successfully grown in the Lower Rio Grande Valley. They appear to be well adapted to conditions in this region.
Kigelia pinnata. Sausage Tree. An evergreen, rapid growing tree that produces dark green, prickly, pinnate leaves. It is of value as an ornamental because of its showy, sausage-like seed capsules which are from twelve to twenty inches long, and are borne on the ends of long, cord-like stems. Plants are very tender to cold. (Bignoniaceae).
Koelreuteria formosana. Bougainvillea Tree. A semi-evergreen tree which produces bright green, pinnate leaves, similar in appearance to the Umbrella Chinaberry tree foliage. The inconspicuous, small yellow flowers are borne over the top of the tree and are followed by numerous, showy, rose-colored, papery capsules. This tree is well adapted and a rapid grower. (Sapindaceae).
Leucaena pulverulenta. Tepehuaje. A rapid growing, thornless, native evergreen tree which resembles a tall fern. It produces typical acacia flowers followed by flat, brown seed pods. It usually blooms after rains, as do its close relatives, the acacias. It reseeds so rapidly that it becomes a plant pest. Another drawback to the use of this tree is its susceptibility to attack by huisache girdlers. There are three related species in the Valley: L. glauca (White Popenac), L. Greggii (Greggs Popenac), and L. retusa (Lead Tree). If one is planning on using a Tepehuaje tree in his plantings, it is best to use the largest growing type which produces the least seeds. (Leguminosae).
Ligustrum japonicum. Japanese Privet, Tree Ligustrum. An evergreen tree ligustrum which produces glossy, dark green, ovate leaves, panicles of fragrant white flowers, and succulent black fruits. (Oleaceae).
Litchi chinensis. Litchee. An evergreen, round-topped tree which produces glossy bright green lanceolate leaflets which are reddish when young, inconspicuous flowers, and very showy, bright red, edible fruits. Well adapted to Valley soils but tender to cold. (Sapindaceae).
Macadamia ternifolia. Queensland Nut, Macadamia Nut. This tree produces shiny, dark green, prickly, oblong leaves and round, edible nuts. It appears to be a slow growing tree. (Proteaceae).
Magnolia grandiflora. Southern Magnolia. This large, glossy-leafed evergreen flowering tree grows very slowly unless given generous supplies of acid forming fertilizers, iron and water. (Magnoliaceae).
Melaleuca armillaris. Drooping Melaleuca. Very dark green foliage; weeping habit of growth; numerous creamy white flowers. (Myrtaceae).
Melaleuca elliptica. Tree Bottlebrush. A pyramidal, upright tree having bright green foliage and small, white bottlebrush flowers.
Melaleuca Leucadendra. Cajeput Tree, Punk Tree. A slender, upright tree having light green, narrowly lanceolate leaves. Corky bark gives the tree its name.
Several species of Melaleuca are being grown at the Experiment Station. The leaves are usually stiff, linear and small; the flower "brushes" are small and white; the capsules cling to the branches, and do not become mature until the second year.
Melia Azedarach var. umbraculiformis. Unbrella Chinaberry Tree. A round headed deciduous tree that produces dark green pinnate foliage and clusters of lilac flowers followed by yellow berries. Extensively used because of its rapid growth and attractive appearance. Being deciduous, it makes considerable litter during the fall and winter seasons and the trees break easily in the wind. (Meliaceae).
Mimosa fragrans. Pink Mimosa. This small tree is native to the Southern and central part of the state. It is partial to limestone soils. (Leguminosae).
Mimosa Lindheimeri. Lindheimers Mimosa. This small tree is native to the Lower Rio Grande Valley along the resacas in Cameron County.
There are two species of pink flowered mimosas native to Texas, both of which are valued for their fern-like foliage and fragrant, pink "power puff" flowers which appear in the spring.
Morus alba var. pendula. Weeping Mulberry. Small round-headed tree with drooping branches. Very ornamental, except during the winter season. (Moraceae).
Morus nigra. Black Mulberry. A very large spreading tree having very dark green ovate leaves and large black fruit. The best variety for this region.
Morus rubra. Red Mulberry. A medium large tree with rough ovate leaves and red fruits produced in such an abundance as to become a nuisance.
Mulberry trees are grown in the Lower Rio Grande Valley for shade and for ornamental purposes. When planted in a poultry yard, the tender shoots, young leaves and berries supply succulent green food, while the spreading top furnishes shade during the hot summer months. All of the types mentioned are deciduous.
Nicotiana glauca. Sacred Mustard Tree, Tree Tobacco. A native, evergreen tree which produces large, bluish-green ovate leaves and clusters of small yellow tubular flowers followed by cup-shaped seed capsules. The Biblical Mustard Tree. (Solanaceae).
Olca europea. Olive. A willowy, evergreen tree that produces narrow oblong gray-green foliage. This is the olive of commerce, but it has no commercial value in this region and makes a poor ornamental. (Oleaceae).
Osmanthus americanus. American Olive. A hardy evergreen tree which produces glossy, dark green oblong leaves about three inches long, and in late fall, fragrant white flowers. (Oleaceae).
Parkinsonia aculeata. Retama, Jerusalem Thorn. A large growing native evergreen tree that has dark green bark, bright green, feathery foliage, and a profusion of yellow flowers having a touch of red at the base of the petals. If properly pruned, it makes a graceful tree. (Leguminosae).
Peltophorum. This U.S.D.A. introduction has proven well adapted to conditions in this region. It is a rapid growing, evergreen tree closely related to the poincianas, producing bright green, pinnate foliage, and a profusion of golden yellow flowers (1-1/2" in diameter) in many flowered racemes, often uniting to form large panicles. (Leguminosae).
Persea americana. Avocado. Since it has been found that the West Indian type of avocado is adapted to soil conditions in this region, and the Mexican types are more cold resistant, an effort is being made to establish plantings of Cuban or West Indian seedlings and graft the hardier, more desirable types onto them. Linda is one of the most ornamental varieties of avocados, but varieties such as Lula, Gottfried and Fuerte are more desirable commersial sorts. (Lauraceae).
Pinus canariensis. Canary Island Pine. This tree produces long, slender branches and light green to blue-green foliage; hard wood; light-gray bark; yellowish brown cones two to three inches long. (Pinaceae).
Pinus echinata. Shortleaf Pine. A tall growing tree of upright habit of growth and having yellow green foliage. This tree is sometimes called Yellow Pine or Spruce Pine. Used to a limited extent in the Valley because of its oddity.
Pinus halepensis. Aleppo Pine. A tall tree having short limbs with yellowish to brown branches; gray bark; light green, sparse foliage, the tufts of leaves being borne on the tips of the twigs; cones two to three inches long.
Several species of pines are being grown in this region, none of which are native. They appear to be well adapted and can be utilized in the landscaping scheme.
Pistachia vera. Pistach. A deciduous, slow growing tree that produces pinnate leaves, medium green in color; the young growth being tipped with red. This tree produces inconspicuous flowers, and small nuts. The pistach appears to be poorly adapted to our conditions. (Anacardiaceae).
Pithecolobium flexicaule. Texas Ebony. A native, evergreen, leguminous tree which produces very dark green bi-pinnate leaves and heads of cream colored acacia-like flowers which are followed by large, thick, dark brown seed pods. (Leguminosae).
Platanus occidentalis. Sycamore. A deciduous tree, native to other parts of Texas, that produces palmately lobed, dull green leaves and heads of flowers containing both pistillate and staminate florets, which are followed by small, brown nutlets. This tree is not recommended because of its habit of shedding its leaves in the fall, and because it has not proven entirely adapted to conditions in this region. (Platanaceae).
Podocarpus macrophylla (longifolia). Japanese Yew, Podocarpus. A slender, pyramidal, evergreen tree which produces dark green, linear-lanceolate leaves in a dense foliage effect. This plant is often used as a tub or porch plant when small, but if given space, it will become a tall tree. (Taxaceae).
Populus lasiocarpa. Chinese Cottonwood. This rapid growing, deciduous tree produces ovate leaves, inconspicuous greenish dioecious flowers and green fruits containing a cottony material surrounding the seeds. Not recommended because of the unsightly bare branches and litter of fallen leaves during the fall and winter months. (Salicaceae).
Prosopis chilensis. Mesquite. This gnarled, native tree is useful as an ornamental. It is easily broken by high winds and is somewhat susceptible to insect attack and disease. It produces dark green, pinnate foliage. Similar to California Pepper in general appearance. (Leguminosae).
Prunus (Laurocerasus) caroliniana. Cherry Laurel. An evergreen tree having glossy, dense, oblong foliage. This tree produces racemes of small white flowers in spring, and small, oblong, black fruits late in the fall. Cherry Laurel is excellent for shearing and is used as a hedge plant. (Rosaceae).
Prunus cerasifera var. Pissardi. Purple Leaf Plum. A small deciduous tree having showy, purplish-red foliage. This plant appears to be well adapted to conditions in this region.
Ptelea Baldwinii. Wafer-Ash. This native wafer-ash is found on the gravel-topped hills along the Rio Grande. The branches are smooth and upright, reaching a height of eight to ten feet. The narrow, aromatic, trifoliate leaves, also point upward. Greenish flower clusters are followed by typical wafer-like winged fruits. The wood is white and tough. (Rutaceae).
Pterocarya stenoptera. Wing Nut. An introduction from the U.S.D.A. A rapid growing, deciduous tree that belongs to the Walnut family. It appears to be well adapted to conditions in the Lower Rio Grande Valley. In the spring it produces pinnate leaves and inconspicuous catkins of flowers, followed by long, drooping racemes of small winged nuts. Very attractive in appearance. (Juglandaceae).
Quercus myrsinaefolia. Japanese Oak. A U.S.D.A. introduction that appears to be well adapted to this region. An evergreen tree having bright green, glossy, lanceolate leaves. (Fagaceae).
Quercus virginiana. Live Oak. A sturdy, round headed, symmetrical, evergreen tree having small obovate, glossy green leaves.
There are no native oak trees in the Valley, but many types are being tried in an effort to find well adapted species of this enduring type of tree.
The Live Oak and Japanese Oak appear to be well adapted to this region. Included in the station collection are specimens of Q. virginiana (Live Oak), Q. myrsinaefolia (Japanese Oak), Q. lyrata (Overcup Oak), Q. minor (Pin Oak), Q. stellata (Post Oak), Q. phellos (Willow Leaf Oak), and Q. agrifolia (Holly Leaf Oak).
Rhus viminalis. Fragrant Sumac. An evergreen, leafy plant up to thirty feet high, that produces bright green, narrow leaves, numerous greenish flower clusters followed by sweetish fleshy fruits. This plant makes slow growth in the Lower Rio Grande Valley and is very susceptible to cotton root rot disease. (Anacardiaceae).
Salix babylonica. Weeping Willow. This is a rather tall growing, slender willow with drooping branches and foliage. Makes rather slow growth and is subject to chlorosis. (Salicaceae).
Salix discolor. Pussy Willow. A small, deciduous tree which is grown for its branches of showy, soft, gray flower heads. The Pussy Willow is not adapted to conditions in this region.
Salix interior. Brittle Willow. A native tree distinguished from the commonly found S. nigra or Black Willow, by its lighter colored branches and very brittle wood. This small willow is found in the vicinity of Brownsville and along the river.
Salix nigra. Black Willow. A very large growing tree where abundant water is available. The commonly found willow to be seen along canal banks in this region.
Samanea Saman. Monkeypod Tree, Rain Tree. An evergreen tree which has light green pinnate foliage. The pink flowers are very similar to those of Albizzia Julibrissin, being large, pink, "powder puffs." The seed pods contain bright red beans. Rapid growing but very tender. (Leguminosae).
Sapium sebiferum. Chinese Tallow-Tree. A tall growing, deciduous tree which produces light green, ovate leaves that turn red in the autumn and remain on the tree during the late fall months. This tree produces inconspicuous flowers, which are followed by oblong white seeds whose waxy covering is used for making candles, soap and cloth dressing. The milky juice of the tree is said to be poisonous. (Euphorbiaceae).
Sapindus Drummondii. Western Soapberry, Wild China-Berry Tree. This deciduous tree is native to many parts of Texas but is nowhere abundant. The trees have scaly, reddish brown bark; pinnate foliage somewhat like the Umbrella China-Berry; panicles of white flowers similar to those of the ligustrum, giving the name "Wild Ligustrum" to this tree. The yellow, grape-like clusters of berries turn almost black at maturity. These berries contain saponin, which can be used as a substitute for soap, and the pulp is valuable for use in the manufacture of floor varish. (Sapindaceae).
Schinus Molle. California Pepper Tree. A tall graceful tree with finely cut foliage, similar to our native Mesquite, that produces small white flowers in panicles, followed by small, rose-colored fruits. Not adapted to Valley conditions as determined by many trials. (Anacardiaceae).
Schinus terebinthifolius. Brazilian Pepper Tree. A spreading evergreen tree having reddish brown bark, reddish stems, and dark green leaves having conspicuous veins. The panicles of small white flowers bloom on the tips of the branches and are followed in the fall by clusters of small red berries.
Two species of pepper trees have been grown in the Lower Rio Grande Valley, but the Brazilian Pepper Tree appears to be the best adapted.
Sophora secundiflora. Mescal Bean, Coral Bean. A native evergreen tree which produces glossy green pinnate leaves, and in spring large clusters of showy purple flowers, followed by seed pods contain bright red seed having medicinal properties. Not recommended. (Leguminosae).
Tabebuia argentea. Bignonia Tree. A rather large tree which produces oblong to lanceolate leaves and in spring a profusion of large, yellow, tubular flowers. A rose flowered species, T. pallida (U. S. D. A. S. P. I #131875), has proven to be fairly well adapted. (Bignoniaceae).
Tamarindus indica. Tamarind. A large, round-topped tree which produces dark green, pinnate foliage. The pods of fruit have a hard, brittle shell, and contain extremely acid pupl that is used in making drinks and meat sauce. The plants are very tender to cold. (Leguminosae).
Tamarix articulata. Athel. A very rapid growing, many branched, dense tree that produces blue-green feathery foliage and panicles of pink flowers. Useful in a sheared hedge or windbreak. (Tamariaceae).
Tamarix gallica. French Salt-Cedar. A small deciduous tree or shrub with plumy, needle-like, green foliage. In the spring it produces numerous pinkish flower racemes. This plant is well adapted, and is recommended for use along the Gulf Coast.
Tamarix odessana. Odessa Tamarisk, Plumy Tamarisk. A small tamarix which produces dark green exceptionally plumy foliage and racemes of pink flowers. One of the most attractive of the Tamarisks.
Taxodium mucronatum. Mexican Cypress. This is a native cypress of the Rio Grande Delta, but it has not been extensively used in landscape beautification. (Pinaceae).
Terminalia Catappa. India Almond, Tropical Almond, Myrobolan Almond. A tall growing, pyramidal deciduous tree whose branches grow at right angles to the trunk. It produces large, ovate to obovate, leathery leaves which turn bright red during the autumn season. Plants grow rapidly but are tender to cold. (Combretiaceae).
Thespesia populnea. Portia Tree, Yellow Flowered Tulip Tree. An evergreen tropical tree that produces light green ovate leaves and large, yellow hibiscus-like flowers followed by small capsules. (Malvaceae).
Thevetia. Tiger Apple. A small, evergreen tree having a round, symmetrical top, and producing shining, bright green, narrow leaves. One variety, T. nereifolia, produces orange colored, tubular flowers; while the other, T. nereifolia flava, produces yellow flowers. Both bear an abundance of green "apples" which are quite ornamental but not edible. The plants somewhat resemble Oleander to which they are related. (Apocynaceae).
Thuja orientalis var. aurea nana. Berckmans Golden Arbor-Vitae. One of the best swarf pyramidal types having the golden yellow foliage. (Pinaceae).
Thuja orientalis var. bakeri. Bakers Arbor-Vitae. A compact, well shaped pyramidal type having bright green foliage.
Thuja orientalis var. beverlyensis. Beverleys Golden Arbor-Vitae. A tall cone-shaped plant having a golden yellow cast to the new growth.
Thuja orientalis var. bonita. Bonita Arbor-Vitae. A good pyramidal type having bright, yellow-green foliage.
Thuja orientalis var. cupressifolia. Ramseys Hybrid Arbor-Vitae. A compact pyramidal type, having bright green foliage.
Thuja orientalis var. glauca. Texas Blue Arbor-Vitae. This is a blue-green type of pyramidal form that may be used along with Rosedale or Bonita.
Thuja orientalis var. rosedale. Rosedale Arbor-Vitae. A good globe type of medium size having feathery blue-green foliage.
Ulmus alata. Winged Elm. A round-topped, native, deciduous tree having branches usually with two opposite, very broad wings. The leaves are ovate, double serrated, smooth above, pubescent beneath. The seeds are elliptic-ovate with narrow wings and two incurved horns at the apex. (Ulmaceae).
Ulmus crassifolia. Cedar Elm. This native, deciduous tree has spreading limbs and slender branches. The dark green ovate leaves are serrated and rough above, pubescent underneath. The flowers are inconspicuous; fruits are oval-elliptic, notched, 1/3-inch long.
Zizyphus Jujuba. Jujube. A deciduous, thorny tree which produces glossy, dark green, ovate leaves, inconspicuous flowers, and maroon-colored fruits which can be utilized in making sweet pickle preserves. (Rhamnaceae).
Ornamentals for the Rio Grande Valley