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TEXAS
MOUNTAIN LAUREL
Texas Mountain Laurel (sophora secundiflora) is indigenous
to the Texas Hill Country and the Trans-Pecos region. This beautiful
evergreen flowering shrub is seemingly surrounded by a veil of intrigue
and mystery. Not well known or planted much outside its home range, Texas
mountain laurel could be utilized as an outstanding landscape specimen
over much of the state if it were better understood.
The controversy begins with attempting to define this plant as a tree or a shrub.
The simple definition has always been that a tree is something we can walk under
and a shrub is something we must walk around. Holding to this definition I would
have to say that Texas mountain laurel is mostly a shrub. Most authors seem to
agree.
Benny Simpson, the recognized expert on woody species in Texas, does not list
Texas mountain laurel in his book Texas Trees but does list Eve's necklace (sophora
affinis) a close relative as being a tree. In the "Texas Native Plants Database" (http://horticulture.tamu.edu:)
Mr. Simpson defines the mountain laurel as a shrub but gives average height as
being 15 to 35 feet (definitely tree size) with an average width of 10 feet.
Sally and Andy Wasowski in their book Native Texas Plants list the Texas mountain
laurel as an ornamental tree and estimate height as anywhere from 6 to 30 feet.
Go figure.
Actually what this should mean to the home gardener is that mountain laurel is
a large shrub or small tree (if you prefer) that may reach 30 feet or more given
enough time and the right conditions. Further study will reveal that most of
us shouldn't worry about that maximum height because this is not a fast growing
plant and by nature a 30 foot specimen would also have to be VERY old. So God
grant you should live long enough to have that problem. At any rate the slow
growth factor will make this shrub easy to control if necessary.
In the home landscape I like to use Texas mountain laurel as a focal point. It
works well anywhere you might use standard yaupon, crepe myrtle, or any of the
mid-sized junipers. The shiny dense evergreen leaves look good in all seasons
and the showy fragrant (reminds most people of grape soda) blossoms are a real
show stopper in early spring. I especially like to plant it where the prevailing
wind can drift that scent toward the house or sitting areas. In my opinion Texas
mountain laurel would not be a good choice for screening because of the slow
growth rate Unless you are very patient or you are lucky enough to find and be
able to afford large specimens to begin with.
Another intriguing issue concerning our mountain laurel is cold hardiness. Before
people like Benny Simpson began researching our native plants, there was little
information as to just how far outside their native habitat these plants could
be grown. Referring to the Texas Native Plants Database again, Mr. Simpson gives
the cold hardiness zone as USDA zone 8. He makes the observation that in climates
colder than zone 8, "flowering is not reliable because of late freezes." He
does not say that the plant will not survive in zone 7 or above he simply states
it may not flower well. However, in doing my own research I turned to the Atlas
of the Vascular Plants of Texas and found that some of the counties (particularly
in the Trans-Pecos) in which sophora secundiflora has been reported are apparently
in zone7.
To further confuse this issue, we recently received a new hardiness zone map
just published by the American Horticulture Society which now pushes the northern
border of zone 8 to the Red River in North Central Texas. Whether this is due
to recent warming trends or a response to better weather data, it does seem to
show some justification for those of us in North Texas to continue to experiment
with zone 8 plants.
Some years ago I had the pleasure of being introduced to Steve and Sherry Bieberich,
owners of Sunshine Nursery in Clinton, Oklahoma. Clinton is smack dab in zone
6 where winter lows typically dip below the zero mark. Yet there is a Texas mountain
laurel growing in the demonstration gardens that judging from its size had been
there for awhile. According to Steve, this specimen had been grown from seed
collected from high elevations of the Guadalupe mountain range. Naturally I was
compelled to purchase a few offspring from his plant to experiment with at our
nursery in Wichita Falls.
Several years later a fine old specimen was found here in Wichita Falls by Phil
Hague, one of our former employees. That spring the plant was putting off a profuse
bloom which resulted in many seeds that were collected by Phil. Judging from
the age of the vacant house at which it was found, the shrub had to be at least
40 and may have been as much as 80 years old. Unfortunately, this venerable shrub
was destroyed the very next year when a new business bought the property, but
thanks to Phil the seedlings live on. This and other sightings of Texas mountain
laurel made it obvious that it had been used as a landscape plant here in North
Texas in years gone by.
My conclusion from all this is that Texas mountain laurel apparently is cold
hardy at least to southern areas of zone 6 and that further experimentation and
selection of hardier genotypes may push it even further north. In the past 12
years I have not seen our mountain laurels damaged by winter cold at all. But
I do agree with Mr. Simpson that the flowers may be lost to late freezes in some
years.
One last bit of intrigue that may help explain the general lack of popularity
is that the plant is quite poisonous. The flowers smell good and the bright red
seeds do resemble some types of candy. However, the seed are extremely hard to
extract from the pod usually requiring a hammer or some other tool to get them
open. History tells us that several Southwestern Indian tribes did use the beans
(also known as mescal bean) as a potion in certain rituals. Used in the right
amount this drug could induce powerful visions. Ingesting too much could certainly
kill a person. You may also find it interesting to note that one of the common
Anglo names for the plant was "big drunk bean." So perhaps a few of
the European settlers may have had a taste as well. While this may cause concern
among some folks the facts are that plant poisonings reported in the United States
are very rare. Besides if you do a little research you will find that you probably
already have some poisonous plants in your landscape. Don't deny yourself the
beauty or the ease of growing Texas mountain laurel. Just don't eat it. OK?
Other criteria for growing mountain laurel concerns soil and soil moisture. The
plant thrives in the highly alkaline limestone soils of the Edwards Plateau.
It will not tolerate soils with an acid ph. Positive drainage is also critical.
This is one of the most drought tolerant shrubs in the landscape industry. Once
established the plant will survive on rainfall alone. In heavy clay soils it
should be planted high and dry. The ideal raised bed for mountain laurel should
contain a good portion of compost mixed with plenty of limestone gravel. As you
may have already guessed, hot weather is not a problem.
Although Texas mountain laurel does spill across the border into Mexico and New
Mexico, Texas is its true home. Indeed, it is found no other place in the world.
In my opinion, sophora secundiflora (a close cousin to our bluebonnet) should
be nominated as our state shrub. Currently the crepe myrtle (from Asia) holds
that honor and distinction. While I do love the crepe myrtle for all its beauty
it seems to me that the plants we choose for the official state emblems should
by their very nature be true Texas natives. Texas mountain laurel accurately
reflects the spirit and tenacity of Texans as it remains green in the cold of
winter, flourishes in the heat of summer, and brings forth astonishing beauty
each spring. Now.......do I hear a second to the nomination? |
