Florida natives are often surprised when we warn our northern visitors about sandspurs – and are met with blank stares or the innocent question: “What’s a Sandspur?”.
‘Sandspurs’ or ‘sandburs’ are a type of grass that produces many thorny and painful burs. On Shell Key, they are concentrated along the edge of the recently removed pine forest in the southern public use area. From a distance, it is hard to distinguish them from other native vegetation.
If you are exploring in this area, wear shoes and tread carefully. You may find yourself in a virtual minefield at any time. The burs stick easily into skin and are quite painful. To remove them, use a piece of cloth or leaf to gently grasp the bur and pull it off. Look for a small spike that may be left behind after removal. You might need tweezers to get it. These can be very painful and get quite sore if not removed.
Longtime visitors to shell key will recall a time with far fewer sandspurs. The current population boom is most likely due to the 10 year eradication effort to remove the ‘exotic’ Australian pine forest in the South Public Use area. For decades, these trees dropped nutrient rich leaves and twigs onto the soil. When they were cut, the richer soil was exposed to sunlight and the sandspurs had a field day (pun intended). Sandspurs are one of those ‘pioneer’ species that will move in to an immature, bare or newly disturbed environment – to restart the eventual progression to a forested area. Once the trees that were planted to replace the pines have matured in a few decades, the sandspurs will eventually die back in numbers … out-competed by a balanced and mature ecosystem.
Sandspurs are summer annuals. They create their “fruit” (burs) over the summer. In fact, sandspurs are an edible grain that can be processed into porridge and flour.
Those that are not carried away by a passing flip-flop will fall to the ground and produce next year’s crop. Like most annuals, sandspurs appear quickly in the spring. They are already nasty by this time, but you can usually remove them without leaving splinters. By late summer and autumn, the sandspurs become more brittle and are more likely to leave splinters. They are dry, sharp and ready to come off the stalk at the slightest bristle.
Eradication of sandspurs is reasonably straight forward in a controlled, home lawn situation. If they are mowed down, they will not be able to make next year’s crop. Although I have seen them adapt by growing sideways and making burs close to the ground. Otherwise, they can be dealt with in the spring – after the new plants have sprouted and before they make fruit (burs). At that time of year, they should be pulled from the ground by hand – being careful not to leave behind burs for next year.
This approach, however, would not work in a wild area like Shell Key. By removing sandspurs in this environment, we are really just resetting the clock to a less mature ecosystem. Remember that these grasses thrive in bare sand. Trying to eradicate sandspurs in a wild environment would be an exercise in futility.
The long-term control of sandspurs on Shell Key will rely on nurturing a mature ecosystem where a diverse and established community of plants and animals keep the sandspurs in check.