ALAMO — Think of this as a flower shop without the usual panic around the holidays.
The U.S. Fish and Wildlife Service’s Native Plant Nursery here, tucked behind the shoulder of the levee bordering the Rio Grande, this year will produce 80,000 native herbaceous plants, shrubs and trees for restoration efforts on federal lands.
Those efforts amount to 300 acres which will be returned to pre-1900 Rio Grande Valley habitat, one suitable for birds, native mammals and, with a little luck, even the endangered ocelot.
“We do everything from the very start of seed collection, seed processing, filling the growing containers — what we call plant bands — filling them with soil mix, propagating the seeds and growing them out,” said Kim Wahl, a plant biologist for the USFWS. “We do that for 80,000 plants here.”
And that number isn’t nearly enough, leading the USFWS each year to contract with native plant growers for even more seedlings to ensure each restoration acre planted receives the right mix of species.
“We grow certain species here, another nursery will grow a certain species, and each one brings them back here and then we get those site-specific mixes ready to go out,” Wahl said.
As you might expect, the native plant nursery here makes an effort to propagate the most difficult native species, like colima, also known as the lime prickly ash, or the heavily-thorned lotebush.
This is how they do it.
You may have heard about the Svalbard International Seed Vault in Norway on a remote Arctic peninsula. A repository there called “Noah’s ark” will hold as many as three million crucial seeds deposited in anticipation of a global catastrophe.
They do the same thing here at the Native Plant Nursery south of Alamo, just not for a zombie apocalypse.
Seeds here are collected and stored in a climate-controlled room in anticipation of a poor production year here in the Valley, one of those seasons of too much dry or, more of a rarity, too much wet.
“We have to have some back-stored so if we don’t have good seed production out there, we still have the ability to pull from our seed storage,” Wahl said. “So we need to have a buffer of five years’ worth of seed stored.”
As you’ve probably guessed by now, processing seeds doesn’t start and end with picking up a handful off the ground and tossing them into a paper bag.
There are four coolers and a freezer that at any one time hold thousands of processed seeds, which have been in some cases cleaned of their outer pulpy berries and sun-dried. Others without a pulp surrounding the seed are sun-dried and either placed in gallon plastic bags or vacuum-sealed.
“If you were to leave the fleshy fruit on there it would just, it would rot,” Wahl said. “So this is elbow bush. Elbow bush is going to have a purple fruit so we come back and de-pulp them by rubbing them against metal-mesh screens.
“We wash all of that fruit off, sun-dry it, and then put them into storage,” she said. “If we were not to sun-dry the seeds and put the seeds in to freeze when they still have too much moisture, the ice crystals would expand and break apart the embryo of the seed.”
With other seeds, like those of the Texas ebony tree, it’s just a matter of breaking the seeds out of the pods once they’re dry. But ebony seeds, alas, have their own special problem — insects and their larvae.
Instead of picking them over seed by seed, the ebony seeds are dumped in a bucket which is then filled with water and those penetrated by insects are found out.
“The bad seeds float, and the good seeds stay at the bottom,” Wahl said.
The seed orchard
The plant nursery uses its on-site orchard to stock the seed storage coolers, but also relies on the institutional knowledge of nursery workers Rene Ruiz and Tino Caldera.
Ruiz and Caldera harvest seeds not just from the orchard here but they collect specific seeds from different species in four counties in the Valley depending on need.
“Rene and Tino have been doing this for so long that they know where, if they’re looking for a certain species, if it’s the right time of year for a certain species, they know where to go to be the most efficient,” Wahl said.
“We’ve learned some pretty good tricks,” Caldera said.
The seed orchard here has several species which have proved more difficult to propagate. One is colima, or prickly lime ash.
“That one is extremely difficult to get it to germinate,” Wahl said.
“And then these don’t look that great right now, but this is lotebush,” she said of a thorny shrub with a sugar hackberry growing out of its center. “Lotebush is one that’s very difficult to get large quantities of seed from.”
Part of the difficulty in obtaining enough seeds from the fruit of some species, like Adelia vaseyi or Texas persimmon, is because they’re so tasty.
“Some of these that are really hard to get the seeds off are the ones that the birds beat us to it,” Wahl said. “The game we’re trying to play is ‘beat the birds.’”
Plant bands and slamming
When it comes to growing native plants, everything isn’t just botany or ecology. When it’s on a scale of production this big, hardware and processes count.
Before the seeds are ready to be sown and grown, the prep work is done to welcome them to their new soil home.
First a mixture of topsoil is sifted, vermiculite and a slow-release fertilizer are added, and topped off with a potting soil and sand mix in individual sleeves called plant bands which are about an inch square by 12 inches long.
These sleeves are made of a biodegradable, cardboard-like paper which will protect the seedling all the way through the planting process. Sixty-four plant bands go into a single crate, which weighs 45 or 50 pounds.
“We start filling that with the soil, and then we put it in here to then slam it,” Wahl said. “This is not anything super high-tech but it gets the job done.”
At the end of the plant band prep, the entire crate is “slammed” by ratcheting up the box a few feet on a pulley, then dropping it swiftly onto a hard surface with a whump six times. It’s no surprise everybody calls the device “the guillotine.”
“We use just gravity to get the compaction in the plant band just right,” Wahl said. “Because if it’s not packed in well enough, they’re going to fall apart during the handling process. We’ll never get it from here out to the field sites.”
The growing benches
The last stop in the production process is the growing benches, which have a total capacity of about 120,000 seedlings.
“We have our growing benches, which are the taller benches … and then we have our staging benches where they go right before we load them up into the trailers and take them into the field,” Wahl said.
Alyssa Stevens, an intern with the U.S. Fish and Wildlife Service this year, waters down crates of plant bands containing guayacan. The guayacan, with its purplish flowers, can reach the size of a small tree and was the first species planted this year.
“It’s our slowest-growing species that we have in the Rio Grande Valley,” Wahl said. “So we start the year with that and we start this as the first one because it needs the longest time to get to size.
“The next one that we start is amargosa, the next slowest-growing one, and then we move through the propagation season going to the fastest-growing seedlings that we have,” she added. “So we usually end with the trees such as ebony, tenaza, blackbrush, the acacia tree species, those are the ones that we end the propagation season with, because they’re going to grow faster than the ones we started with two or three months before.”
“We don’t grow mesquite, and if we did, you would see me with a backpack sprayer on spraying herbicide on all of them,” Wahl said.
Mesquite and huisache, she said, need no help from mere humans when it comes to re-establishing themselves in a restoration effort. They can get there on their own.
The seedlings on the growing benches have mostly been coddled and covered by mesh screens this summer. But now, with planting weeks away, it’s time to toughen them up with more heat and some direct sunlight.
“We’re really getting these ready to go from this stage, the growing stage, out to the planting stage,” Wahl said. “We want them to harden a little bit.”
From 2006 to today
The nursery for native plants used to be just to the east a couple of miles, on the property of the Santa Ana National Wildlife Refuge, before it was relocated here in 2006.
Things were, they say, crowded.
“We were always like, kind of in the way of the fire guys, maintenance, and of course the nursery is always going to be muddy, it’s going to be dirty,” said Rene Ruiz. “So they were always kind of telling us, ‘Hey, could you get these crates out of the way?” and stuff like that.
“Once we came over here, of course, that was not a problem,” Ruiz continued. “I believe it is 120,000 plant bands that we can accommodate here and then we have our staging benches for our stuff and the growers when they deliver it.”
Ruiz has toiled in the South Texas sun for 17 years for the USFWS, all in the pursuit of restoring native flora to its historic place in the Rio Grande Valley ecosystem.
Asked if he had a garden he tends at home as part of a relaxing weekend, Ruiz quickly answered, “No, I don’t do that.”
“I enjoy what I do here, but on the weekends, I would rather be doing something else,” he said.
5 — Nursery acreage
300 — Acres to be restored this year
80,000 — Plants grown this year
120,000 — Annual capacity
230,000 — Total plants put out