We ventured beyond the cracks of sidewalks and included patio pavers, driveway cracks and the danger zone crack between road pavement and curb.
I had a tremendous response from South Texas Border Chapter Texas Master Naturalist members. Thank you!
I’ll start with the most dangerous – not in regard to the plant but to its location.
Velma Schmidt offered this healthy, feathery-looking young growth that appears to be sprouting at a junction of patio pavers, a walkway and a building – and near some possibly important electrical business.
This is a tree – not anything as big as mesquite or hackberry, still it’s a fast-growing tree with a long, strong tap root whose growth might rapidly get stronger than the paver. It’s Mexican Caesalpinia, Caesalpinia Mexicana.
Although locally still called Mexican Caesalpinia, iNaturalist.org lists it as Mexican holdback, Erythrostemon mexicanus. According to a public.asu.edu website, “The Caesalpinia subfamily has been in a state of taxonomic flux over the last 30 years. . . .” I’m not qualified to discuss taxon or flux, just be aware, if documenting an observation of this species onto www.iNaturalist.org, it will be identified as Mexican holdback.
Regardless what we call it, it’s a worthy tree to have – in the right place. It is native to the extreme Lower Rio Grande Valley and south into Mexico. Blooms, seed pods and leaf shapes are classic Legume family – as is its proclivity to self-propagate.
Beautiful yellow clusters of flowers bloom then go to seed off and on throughout the year. The roots contain nitrogen-fixing nodules which allows this tree to grow in poor soil, so there’s a plus if you have problem soil.
The seedpods are fun, dehiscent, they open explosively, shooting far and wide, helping the species to colonize. In my experience, unwanted new growth can easily be pulled out of the soil before it gets taller than six inches. Be vigilant.
If Velma’s Edinburgh find has not already been removed from its confined quarters, it needs to be posthaste! With trees where they shouldn’t be, it’s best to cut the stem as close to the ground/pavement as possible and treat the remaining stump with a liquid like Bonide Vine & Stump Killer that can be purchased online if not found locally. Otherwise, bushy new growth will continue to sprout around the stump. It’s anyone’s guess what the roots are up to.
Obviously, no tree should be encouraged to prosper in the cracks of a sidewalk, driveway or next to the foundation of a structure. Someday nature will take back, certainly. Cement, concrete, blacktop, buildings and structures all will be overtaken, but not yet. If you’re not familiar with Alan Weisman’s 2007 book, “The World Without Us,” published by Thomas Dunne Books, it might settle any nature lovers mind who might be concerned about the amount of cement in the world.
Books aside, there is a mystery plant in our midst. A plant that keeps coming up in various places on our property. It has mystified me for quite a while. Roxanne Balousek sent a photo of a crack plant upstart she found in McAllen that looks awfully similar. iNaturalist.org identified it as annual saltmarsh aster, Symphyotrichum subulatum. I didn’t believe it.
I found a healthy upstart in the crack of our driveway that seems very similar. iNaturalist.org identified it as annual saltmarsh aster. I didn’t believe that either and noticed the second and third choices offered: tall dock and southern seaside goldenrod; fourth was swamp dock and fifth, coreopsis. I’m rather inclined to believe these are dock plants.
A little backstory, I’ve had one of these for several years coming up in our courtyard. The plant may grow to heights of nearly five feet, but never do anything other than grow and push out leaves. I generally get tired waiting for it to bloom and pull it up; I never see it complete a cycle, if indeed it has a normal life cycle, like stalk, leaves, flowers, fruit, seeds.
This year, I have hundreds of these plants all over our property, like a tsunami of weeds. They do not pull up out of the soil. I take solace in that they mow down. I’ve had many observations during bioblitzes of Southern annual saltmarsh aster and the leaves are different than depicted in these mystery plant photos.
Aster plant is shrubby, not a singular stalk and the plant blooms profusely long before it reaches two feet in height. Annual saltmarsh aster is similar to the Southern version. The other day, I spent some time wandering our property uploading to iNaturalist.org similar mystery plant growth. The general consensus is these leaf-only plants are a dock species of some sort. Choices seem to be curled, tall, climbing, swamp, fiddle and willow dock.
I spied a tall dock-like plant at the edge of the farm field adjacent to our property, in front of a red harvester ant residence entrance and surrounded by Guinea grass. Although it is tall, about five feet in height, it was identified as curled dock, Rumex crispus.
Instead of continuing my inexpert and somewhat confusing and frustrating investigation, I’m calling these plants some species in the genus Rumex, which includes about 200 species of dock and sorrels of annual, biennial and perennial herbs in the buckwheat family, Polygonaceae, according to Wikipedia, where it is also noted that the plants are common and have an almost native worldwide distribution.
Dock plants have a long tap root. Good luck pulling out of the cracks of a sidewalk, or from the earth, for that matter. They are leafy, the blooms of some I found at the edge of our resaca, look somewhat like a head of grain, like sorghum. Apparently, dock seedheads feed a lot of birds, who in turn spread the seed. The flowers are wind pollinated, which is interesting, and they are food plants for the larvae of a number of butterflies and moths, according to Wikipedia. I may track the one at the farm field for a while. If anyone can enlighten me about the identity of these mystery plants in the photos, please do so.
Next, let’s get on to one of my favorite plants. Chantel Ortiz and Rosa Flores both sent in pepperweed photos and both are worthy of note because of the artistry of their photos.
Chantel Ortiz found a beautiful example of Virginia pepperweed, Lepidum virginicum, that prospered in the crack where the curb meets the road. She framed it up in an artful composition, giving it a low, eye-level perspective in front of a receding horizon.
Rosa Flores sent in a Southern pepperweed, Lepidium austrinum, sprouting in a wispy, bright green starburst pattern in front of a contrasting white, curved patio stone, the dark soil in the cracks making excellent leading lines.
Well done to both photographers!
Both Southern and Virginia pepperweeds are in the Brassicaceae, or mustard family.
The difference between Southern and Virginia pepperweed: It’s complicated and tiny, so feel free to skip this paragraph. “The Southern pepperweed flowers at the top of the racemes are tiny and densely crammed together; the mature flat, roundish fruits on their pedicels look like green spoons. The flowers bear only two stamens; Virginia pepperweed flowers have four stamens.” A big thank you goes to author Jim Conrad in his “Naturalist Newsletter,” at Backyardnature.net for his original research.
Suffice it to say, Southern pepperweed is an annual herb and is endemic to Texas, Oklahoma and arid northeastern Mexico; Virginia pepperweed, on the other hand, is biennial or perennial, and common in North America coast-to-coast and south through Mexico and Central America and invasive in much of the rest of the world. (Same source as above paragraph.)
No matter which species, pepperweeds are short, bushy plants about 18 to 24 inches in height. Pepperweed can seem prolific but easy enough to pluck out, but really, why? There’s no problem in leaving them where you find them, even in the cracks of pavement. Pepperweeds are pollinated by a variety of insects and bees. Nectar and seeds are food sources. They are a host plant for some of the white butterflies, like the checkered, cabbage and great southern white butterflies. Some birds use a branch of two from the plant in nest building.
Another favorite of mine is plantain, specifically red seeded plantain, Plantago rhosdosperma, which seems to be the most prevalent in our yard. I keep the plants as long as possible wherever I find them and let them go to seed. This year, I found a tiny one growing in the crack of the driveway, the rosette was tiny, but not too tiny to be pushing up a flower head.
Plantain is an annual. It comes up in the winter in the Rio Grande Valley. Most people give it a cursory consideration but can’t really name it. It naturally occurs throughout much of Texas, the Great Plains and the southwest. It grows from a short taproot, first showing a rosette of broad leaves close to the ground. Soon, green spikes shoot up through the rosette that can reach to 14 inches in height. The spikes produce blooms, although the flowers are hardly noticeable.
Toward spring, hundreds of tiny seeds turn the spikes a rusty red color. Because of the short taproot, it’s easy to pluck up these plants if you don’t want them, but the plant actually has tremendous value. It’s used to revegetate wildlife habitats and rangelands for forage; in Texas, the foliage is eaten by Rio Grande wild turkeys, white-tailed deer, cattle, Texas tortoise, scaled and bobwhite quail, mourning doves and caterpillars of the pretty orange virbia moth.
As a conservation plant, plantain has been used in erosion control along streams in various parts of its range. The leaves have anti-inflammatory properties. Plantains are a valued member of our Texas habitat. It’s a keeper wherever it shoots up.
Chantel Ortiz found another street treasure along that road in southeast Weslaco -- one that hopefully survives its precarious position, a beautiful blooming creeper: rose vervain, Glandularia canadensis. It will root at the nodes as long as it can find some soil and form a mat. A good candidate for poor, sandy or rocky soils, a nectar source for butterflies, if not eaten up by rabbits. If Chantel's street crack plant survives a drought and its current road conditions and goes to seed, I’d recommend collecting the seeds (keeping safe from road traffic) and sowing them in the fall in a better environment.
Another offer by Chantel is a prickly sowthistle, Sonchus asper, that braved road/curb hazards.
Don’t turn your back on prickly sowthistle plants. They spring up overnight, especially in cold, crisp moist weather, like our mid-winter – hundreds of them, like a covert invasion. They push forth numerous pretty yellow flowers. Don’t be fooled; they are NOT the beloved dandelions of more northern climates. If you find this plant in your yard, don’t keep it around just to see what it will do and by no means, let it go to seed. The plants can shoot up two to four feet and taller while your back is turned. They have fiendishly jagged leaves. Do not grasp the stem barehanded to pull it up. There are fine, brutal hairs all along the stem and on the undersides of the leaves; it will feel as though you’ve taken hold of a tasajillo, Christmas cholla cactus – pass the tweezers, please.
Both prickly and common sowthistle, Sonchus oleraceus, (no wicked hairs) are a problem. They begin appearing in mid-winter. In the blink of an eye, they can take over a site. The species are native to Europe, Asia and northern Africa and considered invasive in many parts of the world. The deep-rooted plants have a few labels: aggressive, noxious weed, invasive and a difficult-to-control weed because of their rapid plant maturity and prolific production of highly dispersive seeds. Seeds are wind distributed on tufts of white hairs. The stems are hollow. One early spring, I walked through our yard and whacked the plants off near the ground with a machete. They seem to be back in force every year. It’s a continuing battle.
Velma and Roxanne both sent photos of tridax daisy, Tridax procumbens.
Velma’s photo shows the interesting erratic growth and the somewhat prostrate blooms and stems. A great plant to liven up the edge where a sidewalk meets a building.
Roxanne’s photo shows the leaves quite well and a little bud in the left top corner. The leaves are hairy, and in botanical speak, are broadly lanceolate with toothed margins. The plants bloom summer and fall.
Tridax daisy, also called coatbuttons, is a tropical plant native to Mexico and South America but has become an invasive problem around the world. Wikipedia reports that it is “best known as a widespread weed and pest plant.” It is listed as a noxious weed in the United States and has pest status in nine states, Texas being one of those. It is not listed on the Texas Invasive Database site: https://texasinvasives.org/plant_database/. Still, might want to consider clipping those flowers off before they develop seeds. Tridax daisy is a plant I’ve yet to come upon in my travels.
Another new-to-me plant, also offered by Roxanne, is Florida hammock sandmat, euphorbia ophtalmica, an interesting looking plant.
A University of Florida Research and Education web paper claims it as native to Florida, where they call it a landscape weed, which seems like a dichotomy of terms. Its range is from the Southern United States to South America. Apparently, it’s a common sight coming up "between sidewalk cracks along city streets" elsewhere, as noted in another edition of Conrad’s Naturalist Newsletter.
Roxanne happened upon a particularly attractive specimen of this prostrate annual in McAllen. It has classic euphorbia traits in shape, leaf, growth pattern and flowers.
Lisa Adam found the smallest ever blooming tropical sage, salvia coccinea, growing between patio pavers in Weslaco.
Great find, that. A favorite of hummingbirds, it is one of the few native plants that will grow in shade as well as in full sun. It doesn’t take more than one growing season for tropical sage to multiply to a hefty stand of these tubular flowers that bloom nearly all year long. I’ve read tropical sage is a host plant for the painted lady butterfly. Butterflies, bees, flies and wasps also draw nectar from salvia plants.
Lisa also found a tiny pink flower that possibly is a rose evening primrose, Oenothera rosea – the cracks of a sidewalk or patio are not the best growing medium for primroses.
These annual spring lovelies spread by seed and stoloniferous rootstocks. It is native to northern Mexico and Texas. Clusters of pink red-veined flowers bloom in colonies close to the ground. The flowers open in the morning and close in the evening but not before some of our sphynx moths hover around them at dusk, gathering nectar.
Look beyond the sidewalks for the next challenge – a perfect opportunity awaits us at the end of the month – April 26 – 29, 2024. It’s the annual City Nature Challenge - an opportunity for Texas Master Naturalists to earn volunteer hours. The opportunity is open to Rio Grande Valley residents and Winter Texans who want to help document the Valley's native habit by photographing everything around us, not just plants, but anything that moves -- or doesn’t move. Birds, bugs, beetles, mammals, fish, sea beans, shells and other stuff washed ashore – and as iNaturalist.org explains it, signs of life. Check it out, plan to join the challenge. https://www.citynaturechallenge.org/
Previous "Miniature Gardens in the Cracks of the Sidewalk:"
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