July 07, 2019

Cold tolerance of ligustrum and more on invasives

Seeing the the extreme invasiveness of Ligustrum lucidum (Glossy Privet), I am hoping for a cold winter similar to what we had in Texas 36 years ago, when many were killed. In traveling around to different parks, I see efforts being made to eradicate ligustrum, but it is a difficult one to snuff out and continues to re-seed heavily, so the problem is an ongoing one. In the cold outbreak of 1983-84, temperatures remained below zero for nearly 300 hours for parts of Central Texas and D/FW. In December 1989, we had a cold spell that bottomed out with readings of -4 below on the morning of Dec 23, that totally killed some ligustrum and other to the root. In the 2011 freeze event, we had no real damage to Ligustrum or Oleander, although it did kill a fairly large Washington robusta palm tree we had. I have seen Oleander killed to the ground fairly often, but the pink flowered variety seems to be hardy enough to survive almost any winter that we could be dealt here. I had a red flowered one that was killed in the 1983-4 freeze. Sago palm survived easily the 2011 winter, and I have read of a group of these trees in Northern Mississippi surviving since the 1920's, so they should be safe.
Unfortunately there are many other invasives that cold weather will not harm. But a strong cold spell could help to control ligustrum to some extent, perhaps from Austin north anyway. We need any help we can get on this one.


My top invasive shrubs or trees in Central texas:

  1. Glossy Privet (Ligustrum lucidum)
  2. Heavenly Bamboo (Nandina domestica)
  3. Chinaberry (Melia azedarach)
  4. Chinese Pistache (Pistacia chineses)
  5. Chinese Photinia (Photinia serratifolia)
  6. Callery Pear (Pyrus calleryana)
  7. Chinese Tallow Tree (Triadica sebifera)
  8. Persian Silk Tree (Albizia julibrissin)
  9. Tree of Heaven (Ailanthus altissima)
  10. Lilac Chaste Tree (Vitex agnus-castus)

Posted on July 07, 2019 13:48 by lanechaffin lanechaffin | 2 comments | Leave a comment

February 11, 2019

About Live Oaks

This is Quercus fusiformis:

Q. fusiformis in Bexar County, Texas

Quercus fusiformis is the common live oak found in the wild in central Texas. It is more drought-tolerant and cold-hardy than Q. virginiana, which it is sometimes considered a variety of, and is becoming more commonly used as a landscape tree.
Habitat is one of the best ways to distinguish between the two in the wild.
Quercus fusiformis is typically found growing on dry sites, unlike Q. virginiana, which prefers moister conditions and is found along the coastal areas of the southeastern United States. Q. fusiformis is generally accepted to be the hardiest evergreen oak, able to tolerate winters to USDA zone 6a. It has become a popular landscaping tree for its stately form, ability to endure urban conditions, and general hardiness. It is prevalently used for these purposes in Texas and southern Oklahoma, and use is becoming more widespread into the Western US.

Q. fusiformis can appear as a thicket forming shrub or be a large spreading tree that is identical to Q. virginiana. Q. virginiana is known as Coastal Live Oak, or Southern Live Oak. Q. fusiformis is known as Escarpment Live Oak or Texas Live Oak.


Q. fusiformis in Bell County, Texas


Q. fusiformis in Travis County, Texas


Q. fusiformis in Real County, Texas


Q. fusiformis in Tarrant County, Texas


Q. fusiformis in Stephens County, Texas

In it's western range, Q. fusiformis tends to be more easily distinguished from Q. virginiana. But in it's eastern range the differences are less apparent. The state record Q. fusiformis (Ht. 63', circ. 342") is larger than the state record Q. virginiana (Ht. 61', circ. 338"), in height and circumference, but they have the exact same size index of 427 due to the Q. virginiana tree having a greater width.


Note the dotted line along the Balcones Escarpment.

Some authors recognize as distinct species the forms others consider to be varieties of Quercus virginiana. Notably, the following two taxa, treated as species in the Flora of North America, are treated as varieties of southern live oak by the United States Forest Service: the escarpment live oak, Quercus fusiformis (Q. virginiana var. fusiformis) and the sand live oak, Quercus geminata (Q. virginiana var. geminata).
Matters are further complicated by Southern live oaks hybridizing with both of the above two species, and also with the dwarf live oak (Q. minima), swamp white oak (Q. bicolor), Durand oak (Q. durandii), overcup oak (Q. lyrata), bur oak (Q. macrocarpa), and post oak (Q. stellata).

Hybrids & Cultivars - Live oak forms a number of hybrids with other oaks. Cataloged hybrids include crosses with: Q.bicolor (= x nessina); Q. durandii; Q. fusiformis; Q. lyrata (= x comptoniae -- a fast growing tree with goodcold tolerance for hardiness zones 7-9); Q. macrocarpa; Q. minima (= x succulenta -- a Quercus geminatacross); and, Q. stellata (= x harbisonii).In addition to hybrids, there are a number of live oak cultivars: Boardwalk ‘FBQV22’ with a pyramidalshaped crown, a strong central leader, and perpendicular branch angles; Cathedral ‘SDLN’ (PP#12,015) witha dense canopy, a strong central leader, and evenly spaced branches; Grandview Gold (gold colored foliage);Highrise ‘QVTIA’ (PP#11,219) with a strongly upright / columnar crown and dominant leader; Millennium‘CLTF2’ (PP# 11,097) with large dark green leaves, and strong stem and branch taper; Parkside ‘FBQV1’with a dense canopy broadly pyramidal in shape and with perpendicularly attached branches; and,Shadowlawn. Not all cultivars listed in the literature can be found currently in the commercial nursery trade.

According to Turner's Atlas of the Vascular Plants of Texas, Vol. 1, in Texas Q. virginiana occurs only as far west as eastern Williamson County and eastern Bell County. The majority of the occurrences are east and south of Bell County, mostly clustered along the Gulf Coast. Quercus fusiformis, on the other hand, occurs mainly west of the line of counties including McLennan, Bell, Williamson, Travis, Hays, Comal and Bexar—generally, the Edwards Plateau. There is also a grouping in the southern tip of Texas in the South Texas Plains. Additionally, there is an eastern line of counties (including Goliad, DeWitt, Lavaca, Colorado, Fayette, Bastrop, Washington and Brazos) where Q. fusiformis and Q. virginiana overlap. In its eastern range and especially where the two overlap, is where the confusion abounds. Robert Vines in Trees of Central Texas says about Q. fusiformis:
"Although it appears distinct in the western part of its distribution (beyond the Edwards Plateau area and into Mexico), on its eastern range it seems to pass into Q. virginiana with many intermediary variants."
Benny Simpson says this about Q. fusiformis:
"Escarpment Live Oak grows in mottes, attaining heights of 50 feet (72' has been recorded) on almost any alkaline to slightly acid, well-drained soil. It is rather rare on the the true Blackland Prairies, possibly because of the poor internal drainage of those soils, but it does occur in the West Cross Timbers and Grand Prairie, west and north of the Balcones Escarpment on the Edwards Plateau, and, to a lesser degree, east of the Balcones Fault Line on the Blackland Prairies. It grows in hybrid swarms of Quercus virginiana x Q. fusiformis from the Balcones Escarptment to the coastal area and then eastward to the Brazos River, where, on the east side, more or less pure forms of Q. virginiana are encountered."

From Flora of North America:
"The difficulty in distinguishing Texas populations of Quercus fusiformis from Q . virginiana is reflected in a variety of taxonomic treatments, including reducing Q . fusiformis to varietal rank under Q . virginiana . The latter disposition is problematic, however, because Q . fusiformis in northeastern Mexico is amply distinct from Q . virginiana and appears to be more closely related to Q . brandegei Goldmann, an endemic of Baja California, Mexico. Thus, here we assume that the intergradation of Q . virginiana and Q . fusiformis is a result of secondary contact, and is not primary clinal variation. Under this interpretation, Q . virginiana in typical form extends into Texas only as far west as the Brazos River drainage along the coast from there to the escarpment of the Edwards Plateau; most populations elsewhere are either intermediate between the two species or show greater affinity with Q . fusiformis . On the Edwards Plateau, the live oak populations are small trees forming rhizomatous copses (shinneries) and having mostly acute acorns."

Quercus fusiformis was described and the name validly published by John Kunkel Small in 1903.

John Kunkel Small, 1869-1938

From 1897-1933, Small split Q. virginiana into several additional species (e.g. Q. minima (Sargent) Small, and Q. fusiformis). However, Charles Sprague Sargent disagreed with Small and reduced Q. fusiformis to a varietal rank under Q. virginiana.

Charles Sprague Sargent, 1841-1927

In 1961 Cornelius Muller supported species recognition for Q. fusiformis. Muller reported acorn morphology as the major separation between Q. virginiana and Q. fusiformis. Muller also reported morphological integration between Q. virginiana and Q. fusiformis.

Cornelius Herman Miller, 1909-1997

Kevin C. Nixon reported that populations of Q. virginiana were limited to south and east Texas, whereas Q. fusiformis populations were generally located in the central area of Texas from the coastal plain to the Edward’s Plateau. He further reported introgression between Q. fusiformis and Q. virginiana on the Edward’s Plateau that resulted in populations that consist of complex mixes of hybridization between the two species. “The populations of live oak that occur in the area bounded by Columbus, Austin, and San Antonio, Texas can all be considered morphologically intermediate between the populations of Quercus fusiformis that occur on the Edward’s Plateau and Quercus virginiana of coastal southeastern Texas”.

Kevin C. Nixon, Cornell University

Previous research using hybridization studies between Q. virginiana and Q. fusiformis was conducted by H. Ness and by James Hardin. They both concluded that Q. virginiana and Q. fusiformis were one species that adopted different growth patterns in different environments. Presently Q. fusiformis and Q. virginiana are treated as two separate species with the ability to freely hybridize.

James Walker Hardin, North Carolina State

Q. fusiformis in Young County, Texas

Q. virginiana in Aransas County, Texas

Historic Tragedy - Live oaks have dense, hard, and strong wood which is resistant to weather, water, and mechanicalstrain. The massive, low, curved branches and sweeping stems were useless for straight-grained, dried lumberas made from other trees. But the natural growth pattern of live oak made the perfect structural components forwooden sailing ships. Live oak forests first seen by Europeans were storm pruned, extensive, and containedmany massive individual trees. Commerce and war of the 1700’s generated demand for this premium wood forship hull ribs, knees, and support parts. The old growth live oak forests were decimated by European nations,colonists, and early acts of our new nation. “Live-oaking” was a way of life for Northern ship builders. Live oaks accessible to water transportwere targets. Large trees were first cut to see if they were sound, and then divided into the largest and mosteffective parts for use in ship design. Many trees damaged by centuries of storms, were cut only to reveal theywere internally decayed and would not meet the stringent specifications of New England, Atlantic Canadians, orEnglish shipwrights. These cut trees were left to rot. No new trees were planted nor sprouts conserved.Sustainable forest management was nonexistent.Hired gangs of loggers and carpenters from all over were dispatched to hunt and convert live oaks intowooden ship components. The new United States of America federal government attached preserves, laws andbounties to live oak trees. Tree poaching, timber theft on public and private lands, federal agent corruption, andtimber pirates were so common (and results so lucrative), only the demise of easily accessible live oaks and ironboat hulls halted live oak tree slaying and forest destruction. Major parts of the Atlantic coast old-growth liveoak forests were gone by 1870. The Gulf coast live oaks were conserved more effectively for a longer periodof time.

Thinking Big - We today cannot imagine the tree sizes, numbers, and distribution of live oak forests of the 1700’s.What is lost cannot be recreated except through our appreciation of history and a celebration of some of theremaining tree giants (i.e. survivors). See Appendix 1. Live oaks are today visible pillars, ceilings, and walls ofold Southern coastal landscapes and line older streets, squares, and parks, while large wooden sailing ships ofcommerce and war are but a romantic memory.
Although the current accepted scientific name of Texas live oak is Quercus fusiformis, there is no full consensus among taxonomist concerning the taxonomic status of Texas live oak. Some still consider it to be a varietal cline of Quercus virginiana (called variety fusiformis). Moreover, to add to the name confusion in central Texas Q. fusiformis is known to readily hybridize with Q. virginiana. One thing we do know for sure is that Texas live oak is dense wooded and will buckle concrete.

Historical note: Quercus are concentrated in the Northern Hemisphere and number about 600 species. Quercus belongs to a genus steeped in prehistory of Europe and well known to Linnaeus who named it Quercus. This is from the fact that the ancient tree-worshipping tribes often queried very large old oak trees they believed contained powerful spirits that could foretell the future. Live oaks (evergreen oaks) are considered one of the noblest trees in the world and is virtually an emblem of the 'Old South' United States. Consider the following written by Dr. Oliver Wendell Holmes:

"There is a mother-idea in each particular kind of tree, which, if well marked, is probably embodied in the poetry of every language. Take the Oak, for instance, and we find it always standing as a type of strength and endurance. I wonder if you ever thought of the single mark of supremacy which distinguishes this tree from all our other forest trees? All the rest of them shirk the work of resisting gravity: the Oak alone defies it. It chooses the horizontal direction for its limbs, so that their whole weight may tell, and then stretches them out fifty or sixty feet, so that the strain may be mighty enough to be worth resisting. You will find that, in passing from the extreme downward droop of the branches of the weeping willow to the extreme upward inclination of those of the poplar, they sweep nearly half a circle. At ninety degrees the Oak stops short: to slant upward another degree would mark infirmity of purpose: to bend downwards, weakness of organisation."


Posted on February 11, 2019 03:17 by lanechaffin lanechaffin | 1 comment | Leave a comment

January 17, 2019

Identifying Ash trees in Texas

White ash (Fraxinus americana) is native to the eastern part of the state. White Ash typically grows 50-80' tall (up to 125') and 40-50' wide. The lateral leaflets with stalks are strongly whitened beneath. Leaflets are often entire or with very shallow teeth. The bud scars are U-shaped. (Important: A leaf scar is the major botanical feature when keying a green or white ash. The white ash will have a U-shaped leaf scar with the bud inside the dip; the green ash will have a D-shaped leaf scar with the bud sitting atop the scar.) White ash 5-9 elongate leaflets, usually 7. The leaves are 8 to 12 inches in length, with individual leaflets 2 to 6 inches in length. White ash is typically a forest tree prefering moist, rich, deep soil and will grow well in a wide range of pH levels. Dark green leaves become yellow and/or deep purple and maroon in fall.

Some botanists believe that Texas ash (sometimes called Mountain Ash) is a smaller drought hardy variety of white ash (Fraxinus americana var. texensis), usually growing from 30-50' tall and 25-35' wide, from which it can be hard to distinguish. Texas ash (Fraxinus texensis) typically has 5-7 leaflets which are more rounded. Olive green to deep green leaves turn brilliant shades of orange, gold, purple or red in autumn. Texas ash is endemic to limestone areas of southern Oklahoma down through North Central Texas and across the Edwards Plateau.

Green Ash (Fraxinus pennsylvanica) typically grows 50-70' tall with an irregular crown up to 45'. sometimes called River Ash often found in riparian zones along rivers and creeks, floodplain forests and even inundated swamps, but it is adaptable to and often found in other growing environments as well. Green ash typically has 7 leaflets and is so named because the color of its leaves is green on both the upper leaflet surfaces and the lower leaflet surfaces. Lateral leaflets gradually narrowed at base into a narrow wing that runs down the upper part of the leaflet stalk. It is extremely variable in twig and leaf pubescence. Leaflets sometimes toothed. Its winter buds are brown and the bud scars flat-topped, half circles. Leaves are medium to dark green and become yellow in fall.

Berlandier or Mexican Ash (Fraxinus berlandier) is found in moist canyons and stream banks in Central Texas to Trans-Pecos Texas; southward into Mexico where it is called Fresno or Plumero. A smaller round-topped tree rarely over 30' tall. Widely planted as an ornamental in west and southwest Texas and Mexico. The leaves are dark green and thickish, 3-5 leaflets, lancelot or obovate, entire or remotely serrate, glabrous above, glabrous below or a few axillary hairs beneath.

Gregg Ash (Fraxinus greggii) Trans-Pecos found on rocky hillsides and arroyo banks. usually shrubby, to 25'. Leaflets usually 3, sometimes 5-7, thick, olive green above paler beneath, winged.

Fragrant Ash (Fraxinus cuspidata) is found in well drained soil in high altitudes in trans-pecos and in Mexico in rocky canyons. Shrubby, small tree to 25', sometimes forming thickets. Leaflets are 5-7, remotely serrate, lancelot or narrowly ovate, dark green, glabrous above paler below. This ash is unique in having floral fragrance and petals.

The Arizona ash tree (Fraxinus velutina) is commonly called the velvet ash and can reach 50' in height, with a 45-60' open crown in ideal conditions. It is an introduced species often sold at nurseries. Native range is in the high mountains and canyons of the Trans-Pecos and along streams, rivers, and dry streambeds. Marketed as being fast growing and drought resistant, but often problem prone and not recommended in most locations. However, the tree will thrive in less than ideal situations such as urban pollution and poor draining soil. Leaflets 5-7, occasionally 3. The upside and underside of the leaf are often tomentose. The leaf margin is serrated. Fraxinus velutina is closely related to Fraxinus pennsylvanica (Green Ash). Foliage turns yellow in autumn.

Fraxinus americana range

Fraxinus texensis range

Fraxinus pennsylvanica range

Fraxinus berlandier range

Fraxinus cuspidata range

Fraxinus velutina range

Posted on January 17, 2019 17:27 by lanechaffin lanechaffin | 1 comment | Leave a comment

Identifying Redbuds in Texas

The botanical name for the Eastern, or American redbud is Cercis canadensis, and it is a member of the pea family, Fabaceae. Some taxonomists consider both the Texas redbud (Cercis canadensis var. texensis) and the Mexican redbud (Cercis canadensis var. mexicana) natural localized variations of the Eastern redbud.
In East Texas, in well-drained acidic soil, with regular moisture, the Eastern redbud (Cercis canadensis canadensis) in its typical form is found. It can be identified by its medium sized, dull green leaves, which, like all redbuds, emerge after the blossoms have fallen.

In Central Texas and southern Oklahoma, Texas redbud (Cercis canadensis texensis, formerly C. reniformis) is identified by its medium sized, glossy-green leaves and wavy margins, and its ability to tolerate drier, more alkaline soils. more suited to the harsher conditions of Dallas-Fort Worth, Austin and San Antonio landscapes.

The Mexican redbud (Cercis canadensis mexicana) is smaller in stature, ususally multi-trunked, and found in west Texas and northern Mexico. It is extremely drought tolerant, with smaller leaves and ruffled, wavier margins than the var texensis. The leaf pedicels and young branchlets of Mexican Redbud are densely woolly-tomentose and leaves slightly so. No doubt intermediate forms exist in various locations. Some botanist consider Mexican Redbud to be merely a hairy form of Texas Redbud instead of a distinct variety of Eastern Redbud. However, since forms resembling Mexican Redbud have been found in Dallas and Hood Counties it may be more likely to have derived from Eastern Redbud. Source: Robert A. Vines, Trees of Central Texas

All of these native redbuds have similar flowers in early spring. Typical redbud flowers are, of course, not red. They are normally in the purple-pink range, but also can be rosy pink or white.

Cercis canadensis range map

Posted on January 17, 2019 14:50 by lanechaffin lanechaffin | 0 comments | Leave a comment

January 04, 2019

Id these sometimes difficult trees

*Ailanthus altissima (Tree of Heaven, Chinese Sumac)- Leaves alternate, aromatic, usually odd pinnate, 9-41 leaflets, entire leaf margin except near the base where 1-2 pairs of blunt dentate teeth usually occur, fall color yellow. flowers in spring, fruit samara. polygamo-dioecious. Introduced/non-native/escapes cultivation/invasive. https://www.austintexas.gov/sites/default/files/files/Watershed/invasive/2013_Invasives_guide_small.pdf

*Sapindus saponaria L. var. drummondii (Western Soapberry, Jaboncillo)- Leaves alternate, not aromatic, usually odd pinnate, rachis may be winged. 9-18 leaflets (terminal often absent), entire leaf margin, veins of leaflets off center fall color yellow. flowers in spring. fruit translucent amber drupe. dioecios. Texas native. often suckers and forms groves.

*Pistacia chinensis (Chinese Pistache) - Leaves alternate, slightly aromatic, usually even pinnate, occasionally will have terminal leaflet, esp on sapling trees. 10-16 leaflets, entire leaf margin, fall color orange/red. flowers in spring before leaves, fruit is small red drupe turns blue when ripe. dioecious. Introduced/non-native/escapes cultivation/invasive

*Rhus lanceolata (Prairie Flameleaf Sumac)- Leaves alternate, aromatic, odd pinnate, rachis may be winged. 9-21 leaflets, typically 13-17, entire leaf margin, or with small teeth, fall color red. flowers in late spring early summer, fruit red-brown drupe in tight cluster. diocecios. Texas native.

*Juglans nigra (Eastern Black Walnut)- Leaves alternate, aromatic, odd pinnate 13-23 leaflets, finely serrate leaf margin, fall color yellow. flowers in spring catkins, fruit is round nut. monoecious. Texas native.

Posted on January 04, 2019 21:28 by lanechaffin lanechaffin | 3 comments | Leave a comment