David Touchon, NPSOT Boerne Board Member & Secretary
The other day while working with a client on a couple of riparian restoration projects along the Guadalupe, I had the great opportunity to put on the Outdoor Education hat! The primary goal of these riverside efforts is to establish targeted access points along the Guadalupe River, while creating an aesthetically pleasing armored trail between the Riparian riffle areas for my client’s grandchildren’s usage.
The project area was well worn from the July 2025 flood event, and additionally manipulated from debris removal efforts, which sets the table for a creative opportunity. As we walked through the riverbed, we observed a great deal of regrowth within the gravel bars and shoals that seemed to be “stitched” with the footprint of large machinery.
The presence of native pioneer species within the riverbed and the abundant “soft edge” woody species towards the riparian shoulders are proof of nature’s resilience. Bald Cypress, Switch Grass, Rattle Bush, Button Bush and Sycamores in the lower reaches give way to Pecan bottoms festooned with Mealey Blue Sage, Buffalo Ground and Jimsonweed. The upper reaches of the riparian shoulder reveal the classical foundation of Live Oak, Cedar Elm, Sugar Berry, Mustang Grape, Virginia Creeper, Rough Leaf Dogwood and Poison Ivy, albeit draped in light weight flood debris.
Through our walk of the project area, I noticed a couple of curiosities that were most definitely non-native! The presence of Castor Bean within the riverbed makes sense and yet does not completely make sense. I have observed Castor Bean upstream from Comfort, so it makes sense in the downstream areas. Despite being from Eastern Africa, how did this quasi-ornamental end up in the Guadalupe watershed?
Another curiosity within the riverbed was the pretty white florescence of the Poison Hemlock. I have observed Poison Hemlock in many locations along the Guadalupe River and so it makes sense that seeds can being moved around during highwater events. Poison Hemlock can rapidly colonize open/unused areas in a hurry, so be vigilant!
Every part of the Castor Bean and Poison Hemlock are poisonous, so make sure to wear your personal protective equipment! Manual pulling or applying foliar herbicide to Poison Hemlock in the early/late spring is your strongest control option. It is important to note that Poison Hemlock is in the carrot family, so removing the entire root is critical. Mowing or string trimming Poison Hemlock should be avoided, due to the sap becoming aerosolized and inhaled. Castor Bean stands/groves are “less noxious” in a different form, and are easily managed through direct pulling, cutting with lopping shears or a sharp machete.
So, what does this all mean?
There are seasons for everything, and having the timing within your management plan is foundational!
Seasonal variations allow us grow to the plants we enjoy and conversely limit the growth. May is peak Hemlock season while Castor Beans trend towards July. Be bold and fear not! Share your discoveries, carry seed collection jars, keep your work gloves close, and phone a NPSOT friend if you need help!
