Ask Mr. Smarty Plants

Before we get into your questions, we would like to ask if you asked permission from the San Antonia Museum of Art for permission to pick the seeds from the Merremia dissecta (Alamo vine)? Many parks and historic sites have strict rules about removing plant material of any kind from their premises. Even on private farm land, you should obtain permission before you remove anything. We realize that this plant is not protected and can even be invasive where it is growing, so probably no harm was done. However, everyone needs to respect the rights of private property. Oh, yes, you were wondering if the the common name, "Alamo vine," was given it because it grows nearby; probably so, but one of the stories about how the Alamo itself got its name is that there was a nearby stand of cottonwood trees and "alamo" is the Spanish name for cottonwood.

Beyond that, we don't believe we have an answer to your specific questions. You are right, it is native, as you can see from this USDA Plant Profile Map in both Bexar County, from which the plants were taken, and Travis County, where you propose to plant them. If you follow this plant link, Merremia dissecta (Alamo vine), to our webpage on the plant, you will learn all that we know about the plant, including that  native habitat is open and disturbed areas, stream banks, and dry soils in central Texas. Also, under Growing Conditions is this phrase: "Can be very aggressive." In fact, just about any member of the Convolvaceae (morning glory) family can pretty well take over any space. Here is our take on the specific questions:

1. How well does it hold the soil when it grows on streambanks? Our webpage specifically states that it thrives on streambanks.

2. Does it tend to overwhelm and choke out other natives, or would it serve, to some degree, as a nursery plant for the youngest of seedlings? Well, it is aggressive, but plants don't know the difference between native and non-native. If you have an invasive plant, it will push out natives just as readily as non-natives. In the same vein, we have no way of knowing if it can be a "nursery plant," and it is just as likely to "nurse" a non-native.

3. Would it be wise to use these seeds to restore native plants to a streambed here in Travis County where removing invasive species would leave almost nothing behind? It would certainly be worth a try but, again, invasive is invasive. The presently growing invasives in the areas you are concerned with have not only gotten a head start but no doubt have rhizomes and seeds in the ground waiting to quickly pop up when you clear the area. By the time you got the seeds in that you have started, they would likely already be behind.

All of this is not to say that it would not be worth the trouble. You would have to decide if you want to clear out a non-native invasive for an "aggressive" native, and how much work it is going to involve. Most morning glories prefer to climb up on something, trees, trellises, etc., but with nothing to climb they would surely spread on the ground.