NPSOT Logo
npsot_bluebonnet_full_color

Boerne Chapter

In The Battle Against Invasives—Save Some Seeds

By Delmar Cain

During the course of a year I usually go on several fieldtrips, most of which also include an opportunity to see and identify the birds that are the object of the trip or which happen to be along the route. I generally do okay for the birds that I see on a regular basis at my feeders and in my home area. But there is one group of birds where I offer my opinion on identity only if expressly requested—sparrows.

Moth on purple thistle
Julia’s skipper (Nastra julia) on Texas thistle

I have taken the courses (some more that once) by those who are experts. I see the distinctions in their presentations as well as those in the bird books and those in the smart phone bird apps. But when a vesper sparrow or a savannah sparrow flits out of the grass, I might as well flip a coin to give you an answer as to its identity (assuming there are the only two possibilities).

So I have some sympathy when a person asks me on a field trip whether a prickly plant along the trail is a Texas thistle or that other “bad thistle”, Musk-thistle. It can be especially difficult in the early spring when the rosettes of several thistle “cousins”, such as sow thistle, dandelion and white prickly poppy have only three or four leaves. On such occasions it may be best to follow the advice that I heard from one of Kip Kiphart’s friends who was asked the identify of a plant in the early spring. He said, “I will tell you in April.”

Well it is May now and I can do even better. I am including with this article two photographs that hopefully will help you if you are still having trouble making the decision on the thistle at your place. If the thistle is blooming it is easy to see that the flower of the Texas thistle is like small ball sitting on an inverted thimble-like base. There are small prickles on the thimble, but they are not intimidating.

Small spikey plant with buds
Musk-thistle (Carduus nutans)

The forming bloom on the Musk-thistle is larger and covered with sharp stout spines. When fully open, the Musk-thistle flower head may be as large as 3 1/2 inches wide, which is much larger than the small ball on the Texas thistle.

If the thistle in your yard is the “bad thistle”, here is a bit more advice. If you cut a Musk-thistle and it has a bloom on it, cut the bloom off and put it in a trash bag. If you leave the whole plant on the ground, the bloom will still open and allow the dispersal of seeds.

Unfortunately the photographs are probably too late to be of any benefit to Kendall County, which has already spent money on applying herbicide along right of ways of the streets in my neighborhood. There was no Musk-thistle along my street. Now the Texas thistles and the Mexican hats look sick. But the KR bluestem acts like it has just been thrown in the briar patch. There is nothing like giving a fighting chance to that grass imported from China.

Yellow flowers
Lindheimer sida or Showy fanpetals

Two species of plants, which I have found growing in the right of way in the past, are members of the Mallow family. I knew the more common of the two species as “sida” (Sida abutifolia), a plant found in Marshall Enquist’s book, “Flowers of the Texas Hill Country” [but shown with the scientific name of (Sida filicaulis)]. I was a bit surprised to find that, although the USDA Natural Resources Conservation Service plant database shows that it grows natively from Texas to California and also in Florida, sida is not listed in the database for the Wildflower Center in Austin.

In the USDA Natural Resources Conservation Service plant database, its common name is listed as a delicately descriptive “spreading fanpetals”. But don’t be deceived into thinking that it is a delicate plant. It grows in open grassy areas and on bare caliche, making it a natural for a road right of way.

Sida spreads from its base on several stems that hug the ground, sometimes reaching a length of 18 inches. Its serrate leaves are narrow and are 1/4 – 3/4 inch long. The yellow-orange flowers, which definitely resemble small fan blades, are only 1/4 – 1/2 inch wide and close in the shade of the evening.

Yellow flowers growing in gravel
Spreading fanpetals (Sida abutifolia)

The second species that I found on the country right of way is also listed in Enquist’s book. Commonly called Lindheimer’s sida (Sida lindheimeri), it is also known as showy fanpetals. It grows natively only in Central Texas, South Texas, in intermittent counties along the Texas Gulf Coast and in four parishes in Louisiana.

Lindheimer’s sida, named after Ferdinand Jacob Lindheimer, is not as widespread in our area as spreading fanpetals. Also a perennial, it seems to grow better in the sandy soils of its native habitats. In appearance Lindheimer’s sida looks similar to spreading fanpetals, except most of the stems are erect, reaching a height up to 18 inches. The long narrow leaves are 1 – 2 inches in length.

With a common name like showy fanpetals, one would expect a larger flower than that of the small flower of sida. The pale yellow-orange flowers of the showy fanpetals are 1 – 1 1/2 inch in diameter, but still resemble the blades of a fan. Perhaps the larger sized flowers come with a cost to the plant, since Lindheimer’s sida blooms only from May to August. Sida blooms from March to October.

Hopefully, I will still be able to find these two right of way plants in spite of the herbicide treatment. In any event I saved some seeds. Probably Texas thistle, an annual, is gone for the season. But Malta starthistle, that dreaded invasive, also was growing in the right of way. What a price we pay to fight exotic invasive species

A positive ending to this story could be that if you can’t preserve the habitat, at least save some seeds.

Receive the latest native plant news

Subscribe To Our News

Subscribe to emails from the Native Plant Society of Texas.

Receive emails when new posts are added 4-6 times per month, or receive an email once a month.

Or join us on social media