“How do I get rid of sandspurs?” Question from Rena of Morehead City, North Carolina
Answer: Anyone with a yard or beach plagued with sand spurs, most commonly the southern sandbur (Cenchrus echinatus) and the coast or field sandspur (C. spinifex), knows never to walk barefoot. Their painful spurred seeds are covered with needle-like protrusions ready to pierce through skin and even thick clothing like denim jeans. They can also do great harm to children and pets. Thankfully, there are some methods for getting rid of them.
I almost never advocate the use of chemicals, but really bad weeds like these require tough measures. Most experts recommend using pre-emergent herbicides that keep sandspur seeds from germinating in your lawn. Pre-emergent herbicides only work on seeds, not plants. Apply pre-emergents just before your lawn has begun to actively grow and reapply 6-9 weeks later because sandspur seeds do not sprout at the same time. Pre-emergents designed to kill crabgrass, like Preen Lawn Crabgrass Control, also stop annual grasses like sandspurs from sprouting. Be sure to follow the manufacturer’s application instructions.
These are chemicals that you use on weeds after they have sprouted. Very few post-emergent herbicides target sandspur, and most are quite toxic. There are some crabgrass killers that may target sandspurs, but research as shown that they are not that effective, so I do not recommend using them.
Mow your lawn on a schedule and never let it get over 4 inches high. In conjunction, be sure to irrigate it during dry periods to avoid stressing your grass. Mowing low can disable sandspurs from flowering and setting seed.
Plant Fresh Grass in Fall
In early fall, thatch your lawn and plant fresh grass seed suited to your growing area, such as a Bermudagrass blend. Grasses like these will compete with weedy annual grasses, like sandspur, giving them little space to grow. Be sure to fertilize your refreshed lawn once it has begun to grow to give it the best possible head start. There are lots of great organic fertilizers available for turf.
“How can you get rid of nutgrass (aka. yellow nutsedge)? Question from Michael of California.
Answer: What a pain of a weed! Huh? You pull it up, and it just seems to return again and again and again. Here’s why. Nutgrass or yellow nutsedge (Cyperus esculentus) is given its name for the little “nutlet” tubers it produces underground. These nutlets are kind of like little weed bombs because each one will develop into a whole new plant if left in the ground. It’s a devious way for the plants to be foraged or pulled and still remain in the soil ready to reroot, reshoot and grow as if never removed. This is also why foliar weed killers rarely touch it. Nutsedge grows best in moist soil but can tough it out almost everywhere. [As a side note, nutsedge nutlets are also edible and eaten in many cultures. Click here to read more.] We encourage you to view the nutlets and more images for ID on this Washington State webpage before starting the removal process.
Here are some truly effective ways to remove nutsedge without using chemicals.
For small garden infestations, dig up plants to a depth of 10 inches, place weeds and soil on a tarp, and gather up all plant parts, making sure you remove all the nutlets. Nutlets need to be fairly close to the soil surface to sprout and can survive in the soil for 2 to 4 years, so after eradicating most of the sedge from an area, opt for a no-till strategy to keep any deep nutlets from being brought too close to the surface. Then keep a lookout for newly sprouted sedges and just pull or lightly hoe them when they are tiny. Adding a thick layer of organic mulch is also wise.
For large garden infestations, dig it up plants as completely as you can, and then smother the area with weed cloth covered with an additional layer of mulch or leaf compost (for ornamental beds) or straw (for vegetable beds) to keep seedlings and nutlets from resprouting. After a few years, the residual nutlets should be gone and the weed cloth can be removed.
For both cases, keep a lookout for newly sprouted sedges and remove them on sight. Never let them get large enough to set seed.
“Can you tell me what this is and how to kill it? I thought I dug it out already, but it keeps coming back. Its roots run really deep.” -Question from Natalie of Oregon
ANSWER: Sadly, your garden has a field bindweed (Convolvulus arvensis) infestation. This is one of the most notoriously difficult perennial weeds to remove. The vine tightly twines up anything, producing little white flowers that look like tiny morning glories and produce lots of seeds.
Its fast-spreading white-rooted runners spread deep and wide, making them a challenge to dig and collect, especially when they become intertwined with the roots of your shrubs and perennials. Here is the three-stage approach I take to kill it. (BTY, weed killers won’t touch this weed, so put them away!)
Dig out as much of the root system as possible, and remove any vining stems that may have seed developing. When digging white underground runners, gently loosen the soil around each with a trowel, following each until it is fully removed. If you keep even a small piece in the ground, it will re-root and grow. This can be a challenge when working around your garden plants, but be diligent. In some cases, you may have to dig up perennials, remove the bindweed roots from their base, and replant them. Keep watch for any new bindweed shoots that appear and dig them out immediately.
To keep underground stems from returning in really infested areas, cover the area with mulch cloth and mulch it over. After a season, all parts should be smothered, and you can pull up the mulch cloth and resume gardening as usual.
Keep an eye out for nearby bindweed outside of your yard, and at best try to keep it from flowering and moving back into your yard. Talk to your neighbors, if need be.