One weed, spotted spurge, is very common in lawns, and the other, nutsedge, is the scourge of the landscape.
Spotted spurge is a summer annual usually found in or around the lawn, but it also can be found in flower beds. This spurge forms a dense mat by growing close to the ground and has small green leaves growing on each side of a stem. The leaves often have a red spot about halfway down the center vein. When a stem is broken it secretes a milky sap that can be a skin and eye irritant.
Spotted spurge takes over open areas of soil, doesn’t like competition and is a prolific seed producer. Luckily, it’s relatively easy to control. To prevent it’s growth in a lawn, just develop a good, reasonably thick stand of grass that is mowed higher rather than lower, and try to limit any excessive thatch. Early next spring, about the time the forsythia bush blooms or approximately mid-March, apply a pre-emergent such as pendimethalin, which can help limit both crabgrass and spotted spurge along with other broadleaf weeds. Being a summer annual there really isn’t a point in spraying the plant with a herbicide.
Nutsedge is a perennial that can be found throughout the landscape. It is the scourge of the landscape due to its fast-spreading growth and how difficult nutsedge is to control. Nutsedge is often referred to as nutgrass, but it’s not a grass, it is a true sedge that starts from a tuber in the ground that many call a “nut.” Since it’s not a grass, products specific for grass control won’t harm nutsedge.
The most common nutsedge we see is yellow nutsedge, which has leaves thicker than most grasses. If you were to cut the stem of a nutsedge you would see that it is triangular and solid, while grass stems are usually round and hollow. Nutsedge also grows through the use of rhizomes, which are underground stems that then develop into new plants, helping the plant to spread.
Once established, nutsedge can be very difficult to control. However, there are ways to limit the problem. Probably the most environmentally friendly control method – but the hardest on your back and legs – is to simply pull the nutsedge out of the ground as it grows. If you can pull the nutsedge before it gets more than five or six leaves, you can stop it from producing more tubers. If you miss that point and it’s grown larger, just continue pulling it as often as possible and slowly you will deplete the energy reserves of the tuber. However, the tubers can re-sprout three times or more before completely dying, so if you forget and the plant grows back to where it’s again large and healthy, it takes even longer to control.
Plants growing away from other plants can be controlled by spraying – usually more than once – with glyphosate (Roundup). For plants in bluegrass or fescue lawns, you can use MSMA or halosulfuron, which should be applied while the nutsedge plants are small. With larger plants, the herbicides will kill the top part of the plant but not affect the tuber portion, so, again, it can take multiple applications. While there are other products that kill nutsedge, many are not for cool season lawns or for use around all the different plants found in many perennial beds. So read the label first before applying.
Thought for the day: “These days you have to move very fast even to stand still.” —Author unknown.
For more information about these topics call the Utah State University Extension Grand County office at 259-7558 or email Mike Johnson at firstname.lastname@example.org.