Tubb Canyon Desert Conservancy
Sahara Mustard is in Retreat. Let’s “do something.”
When the wildflower fields along Henderson Canyon Rd. were nothing but a thicket of Sahara mustard, when the weed seemed to line every road in town, when it was even growing in the planters at The Mall, a common refrain was, “Why didn’t we do something about Sahara mustard when there were just a few plants instead of the millions we have now?” That was the spring of 2011 when the destructive power of Sahara mustard was on full display, an awesome biological transformation of our desert ecosystem unfolding before our eyes. The take home lesson was the explosive capability of “just a few” Sahara mustard plants.
Although Borrego Springs has become the global leader in Sahara mustard genetic research, much remains to be learned (See “The Fight against Sahara Mustard Heats Up,” The Borrego Sun, 2/23/17). We are still several years from having a safe and effective biocontrol agent. So for the moment, we are left to defend our region with surveillance and manual eradication. Our good luck is that over the last four years Mother Nature has lent us a very big helping hand.
The last four years of drought suggest Sahara mustard seeds are not as hardy as the seeds of our native winter annuals, e.g. sand verbena, desert lily, desert primrose, and desert sunflowers. So in the spring of 2016, despite the fact Sahara mustard had created an extraordinary seed bank in 2011 in the Henderson Canyon fields, it was not the seeds of Sahara mustard that survived four years of drought, but rather those of our native annuals (See Photo 1). Yes, last year there was the occasional Sahara mustard plant—a few dozen per acre; but not the millions of Sahara mustard plants that had prevented the growth of virtually everything else in 2011 (See photo 2).
With the drought Mother Nature has effectively turned back the clock to a time when there are “just a few” Sahara mustard plants. Primarily they are in disturbed soils along the shoulders of roads. They can be easily seen along Borrego Springs Rd. There are some along Highway 78 between Tamarisk Grove and the mouth of San Filipe Canyon. There are plants to be found along portions of Country Club Rd. near Sunset and Church Lane. There are plants along Sunset.
There was a prodigious stand of Sahara mustard along Palm Canyon Dr. at the airport. There were numerous plants along the shoulders of Highway 78 in San Filipe Canyon. Kudos to the Mustard Busters who have removed those plants! It is particularly important to remove Sahara mustard from along our roadways because these are the plants that produce the seeds that hitch rides on our tires to infest new locations. It is also from these initial road shoulder infestations that Sahara mustard eventually spreads into open desert.
Although today’s plants number in the thousands, this is a more manageable number compared to the countless millions of plants that dominated our landscape five years ago. Mother Nature has given us the opportunity to “do something while there are just a few plants.” And that “something to do” is to pull those few plants up by the root—an activity the initiated refer to as “mustard busting.”
The rules for effective mustard busting are few and simple:
- Work in pairs. If you are an experienced mustard buster, take someone with you who has yet to learn the ropes. If you are inexperienced, find someone who can teach you what Sahara mustard looks like. There are a few look-a-likes that you will need to be able to identify and avoid. We find it takes about an hour of training to develop “pattern recognition” for Sahara mustard. Once you have it, your hikes and drive through the desert will never be the same. (See Identifying Sahara Mustard for pictures of Sahara mustard and its look-a-likes.)
- Now that you can identify Sahara mustard, pull each plant you find up by its root.
- If the Sahara mustard plant you have pulled from the soil has not yet begun creating seedpods, you may break off its taproot and leave both the taproot and the leafy portion on the ground. It will not re-root.
- If the Sahara mustard plant you have pulled from the soil has begun creating seedpods, you must break off the stem containing the seedpods, being careful not to dislodge or inadvertently spread the seeds. Place the stem containing the seedpods into a heavy-duty (3-4 mm) trash bag, 30 gallon capacity or greater. (You will need the larger capacity bags for serious mustard busting of mature plants, each plant capable of creating 15,000-20,000 seeds.) Break off the taproot from the remaining leafy portion of the plant. You may leave the taproot and the leafy portion (without seedpods) on the ground.
- Large, mature seedpod stems are rigid and can puncture even heavy-duty trash bags. If this happens, place the punctured bag inside a new bag to make sure you are not inadvertently spreading mustard seeds, which are red and tiny, about the size of the head of a pin.
- When you return home with your heavy-duty trash bags full of Sahara mustard seedpods, inspect your bag(s) to make sure there are no puncture holes. If there are, see #5 above. If there are no puncture holes, pour about a cup of water into the trash bag containing the seedpods. Tightly secure the neck of the bag to make it as air tight as possible. Leave the bag in a sunny location for 7-10 days. Do not open the bag. This process of “solarization” (rotting) will destroy the seeds, making them safe for disposal as ordinary garbage.
- Repeat steps 1-6 as often as possible!
J. David Garmon, MD