Common Noxious & Invasive Weeds in Pinal County Ditches

Irrigation ditches, roadsides, and disturbed soils often become entry points for invasive weeds. These species spread quickly, compete with native plants, disrupt wildlife habitat, and can interfere with irrigation systems or increase wildfire risk.

Sahara Mustard (Brassica tournefortii)

Habitat
Disturbed soils, roadsides, fields, desert washes

Problems
Forms dense stands that crowd out native wildflowers and reduce biodiversity.

Spread
Produces thousands of seeds that spread easily by wind, vehicles, and soil disturbance.

Stinknet (Oncosiphon piluliferum)

Habitat
Roadsides, vacant lots, disturbed desert soils

Problems
Forms dense infestations that displace native plants and create highly flammable vegetation.

Status
Arizona Class B Noxious Weed

Buffelgrass (Cenchrus ciliaris)

Habitat
Roadsides, disturbed desert slopes

Problems
Creates continuous fuel that allows fire to spread across desert landscapes that historically rarely burned.

Salt Cedar / Tamarisk (Tamarix spp.)

Habitat
Ditches, riverbanks, washes

Problems
Alters water flow, increases soil salinity, lowers water tables, and replaces native riparian vegetation.

Russian Thistle (Salsola tragus) – Tumbleweed

Habitat
Agricultural fields, roadsides, disturbed soil

Problems
Spreads by tumbling seed heads and rapidly colonizes bare ground.

Red Brome / Chismus (Bromus rubens)

Habitat
Disturbed desert soils, roadsides, washes

Problems
Creates dense annual grass cover that increases wildfire risk.

London Rocket (Sisymbrium irio)

Habitat
Urban areas, roadsides, disturbed soils

Problems
Common winter annual that quickly dominates disturbed ground after rainfall.

Johnson Grass (Sorghum halepense)

Habitat
Agricultural ditches, irrigated fields, disturbed soils

Problems
Aggressive perennial grass that spreads through rhizomes and seed. Competes with crops and native plants.

Bermuda Grass (Cynodon dactylon)

Habitat
Irrigation ditches, lawns, agricultural areas

Problems
Spreads aggressively through stolons and rhizomes, forming dense mats that are difficult to remove.

African Rue (Peganum harmala)

Habitat
Roadsides, disturbed soils, desert flats

Problems
Highly drought tolerant invasive plant that can dominate disturbed desert landscapes. Toxic to livestock.

Puncturevine / Goathead (Tribulus terrestris)

Habitat
Roadsides, disturbed soils, urban areas

Problems
Produces sharp seed burrs that injure livestock, pets, and bicycle tires.

Why Ditch Weed Management Matters

Irrigation ditches and disturbed soils often act as invasion corridors where weeds establish and spread into nearby farms and desert habitats.

Early detection and control helps:

  • Maintain irrigation infrastructure
  • Reduce wildfire risk
  • Protect native plants and wildlife
  • Prevent weeds from spreading into surrounding desert ecosystems

Beneficial Native Plants for Ditches and Disturbed Desert Areas

Globe Mallow (Sphaeralcea spp.)

Habitat
Roadsides, washes, disturbed soils

Beneficial Insects
Mallow bees (Diadasia species), sweat bees, leafcutter bees

Butterflies
Painted lady, gray hairstreak, checkered skipper

Birds
Lesser goldfinch, house finch, insect-eating birds

Ecological Role
One of the most important pollinator plants in disturbed desert habitats.

Desert Milkweed (Asclepias subulata)

Habitat
Desert flats, washes, disturbed soils

Beneficial Insects
Milkweed bugs, milkweed beetles, native bees

Butterflies
Monarch butterfly (host plant), queen butterfly

Birds
Verdins, gnatcatchers, insect-eating birds attracted to caterpillars

Ecological Role
Essential host plant for monarch butterflies and supports many pollinators.

Desert Broom (Baccharis sarothroides)

Habitat
Ditches, washes, disturbed soils

Beneficial Insects
Native bees, hoverflies, parasitic wasps

Butterflies
Painted lady, skipper butterflies

Birds
Verdins, phainopepla, sparrows

Ecological Role
One of the most important late-season nectar plants in the desert.

Sacred Datura (Datura wrightii)

Habitat
Washes, desert edges, disturbed soils

Beneficial Insects
Native bees, beetles

Butterflies / Moths
Hawk moths (sphinx moths)

Birds
Birds feed on insects attracted to the plant

Ecological Role
Supports important nighttime pollinators.

Fourwing Saltbush (Atriplex canescens)

Habitat
Desert flats, washes, disturbed soils

Beneficial Insects
Native bees, beetles

Butterflies
Hairstreak butterflies

Birds
Gambel’s quail, sparrows, doves

Mammals
Jackrabbits, mule deer

Ecological Role
Excellent soil stabilizer and wildlife forage plant.

Bush Muhly (Muhlenbergia porteri)

Habitat
Desert slopes, washes, disturbed soils

Beneficial Insects
Grasshoppers, beetles

Butterflies
Skipper butterflies

Birds
Sparrows, quail, seed-eating birds

Ecological Role
Provides cover and seed for birds while stabilizing soil.

Brittlebush (Encelia farinosa)

Habitat
Desert slopes, roadsides, disturbed soils

Beneficial Insects
Native bees, hoverflies, beetles

Butterflies
Painted lady, checkered white

Birds
Finches and insect-eating desert birds

Ecological Role
Important early-season pollinator plant.

Why These Plants Matter

These native plants support insects that feed birds, reptiles, and small mammals. Those animals then support predator species such as hawks and owls.

Healthy native vegetation helps rebuild the natural food chain:

Plants → Insects → Birds & Small Mammals → Owls & Hawks

Supporting native plants is one of the most effective ways to improve wildlife habitat while reducing pest problems naturally.

Do’s and Don’ts of Weed Management

Effective weed management focuses on early intervention, selective control, and restoring native plant systems. Poor management practices can unintentionally worsen invasive plant problems.

DO

Target Specific Problem Species

Focus on selective weed removal rather than eliminating all vegetation. Removing only invasive plants helps protect beneficial native plants and the wildlife they support.

Address Problems Early

Control weeds while infestations are small. Early removal prevents large seed production and reduces long-term management costs.

Spray Herbicides When Plants Are Actively Growing

Herbicides are most effective when plants are healthy and actively growing, allowing the plant to absorb and transport the treatment through its system.

Combine Weed Removal with Native Plant Restoration

After removing invasive plants, reseed or plant native species. Healthy native plant communities help prevent invasive weeds from returning.

Improve Soil Conditions

Maintaining healthy soils and appropriate ground cover reduces open space where invasive weeds can establish.

Manage Water in Problem Areas

Reduce unnecessary water in areas prone to invasive weeds. Many invasive species thrive in over-watered or disturbed environments.

DON’T

Don’t Use Blanket Herbicide Treatments

Broadcast herbicide applications can kill the native seed bank and beneficial plants, leaving bare ground where invasive weeds can quickly return.

Don’t Cover Soil with Decorative Rock

Rock landscaping often creates ideal conditions for weeds. Seeds accumulate between rocks and are difficult to remove without herbicides.
Sand or natural soil surfaces are easier to maintain and allow native plants to establish.

Don’t Leave Bare Soil

Bare ground encourages invasive plants such as Sahara mustard, stinknet, and Russian thistle to establish quickly.

Don’t Ignore Early Infestations

Small patches of invasive weeds can quickly expand if not addressed early.

Best Long-Term Strategy

Successful weed management combines:

  • Early detection
  • Selective removal of invasive species
  • Strategic herbicide use when necessary
  • Native plant restoration

Healthy native plant communities are the most effective long-term defense against invasive weeds.