If you live in the desert, you already know that keeping a green lawn takes work. But the real battle is against the common lawn weeds in Arizona that seem to thrive no matter what you do. These weeds are tough, fast-growing, and perfectly adapted to our heat and dry soil.
Let’s be honest: nobody wants a yard full of stickers and ugly patches. The good news is that you can win this fight. You just need to know what you’re up against and how to handle each weed the right way.
Common Lawn Weeds In Arizona
Before you grab a spray bottle, you need to identify the enemy. Arizona lawns face a unique set of weeds that laugh at heat and ignore drought. Below is a breakdown of the most persistent offenders, how to spot them, and what actually works to get rid of them.
Bermudagrass As A Weed
Yes, bermudagrass is a common lawn grass here. But when it invades flower beds or takes over a fescue lawn, it becomes a weed. It spreads fast through runners and underground rhizomes.
- Identification: Fine-textured, light green leaves that form a dense mat. It grows low to the ground.
- Why it’s tough: It goes dormant in winter but comes back strong in spring. It survives heat and foot traffic.
- Control: You can’t just pull it. Use a selective herbicide with fluazifop or fenoxaprop. Apply in late spring when it’s actively growing.
Spurge (Prostrate Spurge)
This weed hugs the ground and forms a flat, circular mat. It loves compacted soil and full sun. If you see a weed that looks like it’s glued to the dirt, it’s probably spurge.
- Identification: Small, oval leaves arranged opposite each other. Stems have a milky sap when broken.
- Why it’s a problem: It produces thousands of seeds. One plant can take over a large area quickly.
- Control: Hand-pull when soil is moist. For large areas, use a pre-emergent in early spring. Post-emergent herbicides with 2,4-D work well.
Goosegrass
Goosegrass looks like a clump of coarse grass. It’s common in thin lawns and along sidewalks. It loves heat and compacted soil, which makes it a perfect fit for Arizona.
- Identification: Flat, dark green leaves that grow in a rosette pattern. The center of the plant is white or silver.
- Why it’s stubborn: It germinates later than crabgrass and survives mowing well.
- Control: Pre-emergents applied in late spring are key. For existing plants, spot-treat with a non-selective herbicide or pull by hand.
Dandelion
Everyone knows dandelions. They have bright yellow flowers that turn into white puffballs. In Arizona, they appear in cooler months and early spring.
- Identification: Deeply lobed leaves in a rosette. Single yellow flower on a hollow stem.
- Why it’s annoying: The taproot goes deep. If you don’t remove the whole root, it grows back.
- Control: Use a dandelion weeder to pull the entire root. Apply a broadleaf herbicide in fall for best results.
Purslane
Purslane is a succulent weed with fleshy, reddish stems. It grows flat on the ground and can survive extreme drought. It’s actually edible, but you probably don’t want it in your lawn.
- Identification: Thick, paddle-shaped leaves. Stems are red or purple. Small yellow flowers.
- Why it’s persistent: It stores water in its leaves. Even after you pull it, pieces left on soil can reroot.
- Control: Hand-pull and remove all plant parts. Use a pre-emergent in spring. Post-emergent herbicides with dicamba work well.
Nutgrass (Nutsedge)
Nutgrass looks like a tall, bright green grass, but it’s actually a sedge. It grows faster than your lawn and stands out like a sore thumb. It loves wet spots and overwatered lawns.
- Identification: Triangular stem (roll it between your fingers). Shiny, yellow-green leaves. Grows in clumps.
- Why it’s hard to kill: It has underground tubers (nutlets) that store energy. Pulling leaves doesn’t kill the tubers.
- Control: Use a selective herbicide made for sedges, like halosulfuron. Apply when nutsedge is actively growing. Do not pull it; that spreads the tubers.
Clover (White Clover)
Clover is a low-growing weed with three round leaflets. It has white or pink flowers. It thrives in lawns that are low on nitrogen.
- Identification: Three leaflets, often with a white chevron. Creeping stems that root at nodes.
- Why it appears: It’s a sign of poor soil fertility. It fixes its own nitrogen, so it outcompetes grass in poor soil.
- Control: Fertilize your lawn properly to make grass stronger. Use a broadleaf herbicide with 2,4-D and dicamba. Hand-pull small patches.
Spotted Spurge
This is a close relative of prostrate spurge. It has a red or purple spot in the center of each leaf. It grows fast and spreads wide.
- Identification: Small, hairy leaves with a red spot. Milky sap. Grows flat.
- Why it’s tough: It produces seeds within weeks of germinating. It can complete its life cycle fast.
- Control: Same as prostrate spurge. Pre-emergent in early spring. Post-emergent with 2,4-D. Hand-pull small plants.
Wild Onion And Wild Garlic
These weeds look like thin, wispy grass blades. But when you crush a leaf, it smells like onion or garlic. They grow in clumps and can take over thin lawns.
- Identification: Hollow, round leaves (onion) or flat, solid leaves (garlic). Smell is the giveaway.
- Why they’re annoying: They grow from bulbs. If you don’t remove the bulb, they come back.
- Control: Dig up the bulbs in early spring. Use a herbicide with 2,4-D or dicamba in fall when bulbs are storing energy.
Prevention: Stop Weeds Before They Start
Stopping weeds is easier than killing them. A healthy, thick lawn is your best defense. Weeds love bare spots and thin grass.
Mow At The Right Height
Mowing too short stresses your grass and gives weeds sunlight. Keep bermudagrass at 1 to 1.5 inches. Keep fescue at 2.5 to 3 inches. Taller grass shades the soil and prevents weed seeds from germinating.
Water Deeply But Infrequently
Frequent, shallow watering encourages weed seeds to sprout. Water deeply to encourage deep grass roots. Let the soil dry out between waterings. Most Arizona lawns need water every 3 to 5 days in summer.
Fertilize Properly
Weeds like clover and spurge thrive in poor soil. A balanced fertilizer helps grass outcompete them. Use a slow-release nitrogen fertilizer in spring and fall. Don’t over-fertilize; that can burn grass and feed weeds.
Use Pre-Emergent Herbicides
Pre-emergents create a chemical barrier that stops weed seeds from growing. Apply them twice a year: once in late winter (for summer weeds) and once in early fall (for winter weeds). Water them in after application.
- Spring pre-emergent: Apply when soil temperature reaches 55°F (usually February or March).
- Fall pre-emergent: Apply in September or October.
- Products: Look for prodiamine, dithiopyr, or pendimethalin.
How To Kill Existing Weeds
If weeds are already growing, you need a plan. Here’s a step-by-step approach.
Step 1: Identify The Weed
Use the descriptions above to figure out what you’re dealing with. Different weeds need different treatments. Spraying the wrong herbicide wastes time and money.
Step 2: Choose The Right Herbicide
There are two main types: selective and non-selective.
- Selective herbicides: Kill specific weeds without harming grass. Good for broadleaf weeds in lawns.
- Non-selective herbicides: Kill everything they touch. Use for spot-treating weeds in cracks or bare areas.
For most lawn weeds, a selective herbicide with 2,4-D, dicamba, and MCPP works well. For grassy weeds like goosegrass, you need a different product.
Step 3: Apply At The Right Time
Herbicides work best when weeds are actively growing. Apply in the morning when temperatures are below 85°F. Avoid windy days to prevent drift. Don’t apply before rain.
Step 4: Follow Up
Most weeds need more than one treatment. Wait 2 to 3 weeks and reapply if needed. Hand-pull any survivors. Keep your lawn healthy to prevent new weeds.
Organic And Natural Control Methods
If you prefer not to use chemicals, there are options. They take more work but can be effective.
Hand-Pulling
For small patches, hand-pulling works. Water the area first to loosen soil. Use a weeding tool to get the whole root. Remove all plant parts, especially for purslane and spurge.
Corn Gluten Meal
This is a natural pre-emergent. It stops weed seeds from germinating. Apply it in spring and fall. It also adds nitrogen to the soil. It won’t kill existing weeds, so use it as prevention.
Vinegar Solutions
Household vinegar (5% acetic acid) can kill young weeds. It works best on sunny days. It’s non-selective, so be careful around grass. For tougher weeds, use horticultural vinegar (20% acetic acid). Wear gloves and eye protection.
Boiling Water
Pouring boiling water on weeds in cracks or patios kills them instantly. It’s cheap and chemical-free. Be careful not to splash your grass or plants.
Mulching
In garden beds, a thick layer of mulch prevents weed seeds from getting sunlight. Use wood chips, bark, or gravel. Apply 2 to 3 inches deep.
Seasonal Weed Calendar For Arizona
Weeds have seasons. Knowing when they appear helps you plan your attacks.
Winter Weeds (November To March)
These weeds grow during cool weather. They include:
- Annual bluegrass (Poa annua)
- Henbit
- Shepherd’s purse
- Wild onion and garlic
Apply pre-emergent in October. Hand-pull or spot-treat in winter.
Summer Weeds (April To October)
These weeds love heat. They include:
- Crabgrass
- Goosegrass
- Spurge
- Purslane
- Nutgrass
Apply pre-emergent in February or March. Use post-emergent herbicides in late spring and summer.
Year-Round Weeds
Some weeds, like bermudagrass and dandelion, can appear any time. They are more active in warm months but can survive mild winters.
Common Mistakes When Dealing With Arizona Lawn Weeds
Even experienced gardeners make errors. Avoid these common pitfalls.
- Mowing too short: Scalping your lawn invites weeds. Keep grass at the recommended height.
- Overwatering: Wet soil encourages nutgrass and spurge. Water only when needed.
- Using the wrong herbicide: Spraying a broadleaf killer on grassy weeds won’t work. Identify first.
- Applying herbicide in heat: High temperatures can burn your lawn and reduce herbicide effectiveness.
- Ignoring soil health: Compacted, poor soil grows more weeds. Aerate and fertilize regularly.
FAQ: Common Lawn Weeds In Arizona
What is the most common weed in Arizona lawns?
Bermudagrass invading other grass types is very common. Spurge and goosegrass are also widespread. It depends on your lawn type and care routine.
How do I get rid of nutgrass in my Arizona lawn?
Use a selective herbicide made for sedges, like halosulfuron. Apply when nutgrass is actively growing. Do not pull it; that spreads the tubers. Improve drainage to reduce wet spots.
Can I use vinegar to kill weeds in my lawn?
Yes, but carefully. Vinegar is non-selective and will kill grass too. Use it only for spot-treating weeds in cracks or bare areas. It works best on young weeds in full sun.
When should I apply pre-emergent in Arizona?
Apply pre-emergent twice a year. First in late winter (February or March) for summer weeds. Second in early fall (September or October) for winter weeds. Water it in after application.
Why do I have clover in my lawn?
Clover often appears in lawns that are low on nitrogen. It fixes its own nitrogen, so it outcompetes grass in poor soil. Fertilize your lawn properly to reduce clover. You can also use a broadleaf herbicide.
Final Thoughts On Arizona Lawn Weeds
Dealing with common lawn weeds in Arizona is an ongoing job. But you don’t have to live with a weedy yard. Start by identifying what you have. Then choose the right control method. Prevention through proper mowing, watering, and fertilizing is your best long-term strategy.
Remember that no lawn is perfect. A few weeds here and there are normal. Focus on keeping your grass healthy and thick. That alone will reduce most weed problems. Be patient and consistent. Your lawn will thank you.
If you need more help, talk to your local extension office or a trusted garden center. They know what works in your specific area. And don’t be afraid to ask questions. Every Arizona lawn owner has been where you are now.
Keep at it. Your green lawn is worth the effort.