Rent Shop Volunteer Join

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Friday - September 09, 2016

From: Bandera, TX
Region: Southwest
Topic: General Botany, Propagation, Trees
Title: Propagating a white cultivar of Texas Mountain Laurel (Sophora secundiflora
Answered by: Nan Hampton

QUESTION:

I am trying to propagate a white cultivar of the Texas Mountain Laurel. I plan to use bee sticks and pollinate the plant. Are the plants self fruiting or do I need to find another white mountain laurel somewhere to try and do this? What would be a good item to cover the blooms with to avoid promiscuity?

ANSWER:

First, let's talk about the breeding system of Sophora secundiflora (Texas mountain laurel).  They have perfect flowers with both male and female components within each individual flower.  The flowers of Texas mountain laurel are typical "pea" flowers with the stigma (female part) and the stamens (male parts) enclosed within the keel of the flower.  This would seem to be an ideal setup for self-fertilization inside the unopened keel of the flower.  However,  the very fragrant flowers are enthusiastically visited by bees and other insects that are able to push inside the keel to obtain the nectar and, in the process, collect pollen.  It is VERY unlikely that the flowers self-fertilize in this way.  However, we don't have any information as to whether the flowers are self-compatible or not.  In other words, if a bee visited one flower on the tree and then brought the pollen from that flower to a different flower on the tree, would the pollination result in fruit?   It is certainly worth trying to pollinate the flowers with pollen from other flowers on the tree. 

If you have access to another Texas mountain laurel with white flowers, it would be good to try using pollen from that tree, too, because, even if the flowers on the same tree are self-compatible, the introduction of genetic diversity is likely to increase the amount of fruit set over those of the self-pollinated flowers. That said, you need to realize that white cultivars can be from mutations of different genes and the combination of the two might result in the two compensating for the mutation that the other has and not resulting in white flowers at all.

An article on Wikipedia discusses pollination bags and lists bags made of different materials and their characteristics.  There is also a set of criteria for a good pollination bag.  Among those criteria are that the pollination bag:

  • be made of material strong enough to withstand abrasion from wind, rain, birds, etc.
  • be porous enough that air and moisture is able to pass through, but not so porous that pollen grains can enter
  • allow the penetration of sunlight so that photosynthesis can continue to occur to tissues within the bag

The main criteria for a good pollination bag should be that ambient conditions are maintained within the bag while preventing the entrance of pollinators or wind-blown pollen.

Here are some suppliers of pollination bags that I found on the Internet:

You can find more suppliers by searching the Internet for "pollination bags".

The pollination bag that you use will be tied around the stem of the flower cluster as soon as the flower buds form to prevent insect pollinators from entering the flowers.  In order to prevent injuring the stem, you can first wrap a cotton ball around the stem before you tie the bag, with a string or twist tie, securely around the stem.

Finally, you could make your own bee sticks, buy pollination wands or use a small paint brush like Gregor Mendel used in his famous pea plant crosses.

 

From the Image Gallery


Texas mountain laurel
Sophora secundiflora

More Trees Questions

Are Ashe Junipers dying from mite damage in Austin?
August 08, 2011 - If Ashe Juniper needles are turning brown and dropping off the trees because of drought, and not disease, do the needles ever come back, or have the tree limbs died? What if the cause is mites, not ...
view the full question and answer

Tree that will not interfere with hardscape in San Diego
February 07, 2009 - I am looking for a small tap root tree that will reach max height of 20-25 ft. The area is only about 4 to 6 ft. to the house slab or driveway which I need to be very careful so it doesn't crack the...
view the full question and answer

Non-flowering mimosas in Texas
July 08, 2008 - I have two mimosa trees, about 3 years old. Both were grown from volunteer seedlings. Neither have flowers nor have they produced seed pods. Are they too young or do they need a source of pollenation...
view the full question and answer

Grey Goo Coming from red Oak in Manchaca TX
May 13, 2013 - I have a large Red Oak in my yard that appears to be weeping some sort of grey goo from parts of the trunk. What is this goo and do I need to treat it and if so how? I'm happy to come by the Wildflow...
view the full question and answer

Need help with a misshapen Monterey Oak in Austin, TX
March 11, 2010 - In the Fall of 2008, I purchased a very tall Monterey Oak from TreeFolks at the Burger Center Sale. Since the wind was so high, all the tall trees were on the ground, and I guess that is why I did no...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.