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Say “No” to Noxious Weeds: Salt Lake Valley’s Perennial Intruders

All residential weeds are annoying, yes…but some are actually noxious.

A plant is deemed to be noxious if it poses significant danger to the surrounding ecosystem, agriculture, recreation, and health of the community. 

Sadly, the Salt Lake Valley has no shortage of these obnoxious intruders. On top of opting for professional care for your yard, you can help preserve Utah’s precious resources by keeping an eye out for these perennial leafy lurchers:

Hoary Cress — Lepidium draba

Also known as “Whitetop”, this plant’s small white flowers have four petals, giving it a pretty flat-topped appearance— Don’t let it fool you, though!

Flowering May through June, this forb grows 10 to 24 inches tall and forms dense monocultures that displace our beloved native plants. Not only that, but it can cause respiratory allergies!

Keep an eye out for blue-green lance-shaped leaves and heart-shaped seed capsules— They are being fueled by about 30-inch roots!

The hoary cress’s extensive root system requires diligent care to do away with: 

  • Call up a lawn care expert for the correct weedicide
  • Remove new shoots within 10 days of emergence
  • Mow often to stress it and support chemical effectiveness 

Field Bindweed — Convolvulus arvensis

This weed’s whitish pink flowers are shaped like a funnel, flaunt two bracts below their base, and only last for a day— Despite their short life, the stems below them cause double the trouble!

Blooming in late June, this forb’s fast-growing vine-like stems can strangle your precious hedges, flowers, and veggies.

Look out for blue-green leaves that are shaped like arrowheads— Then, get ready for battle!

The field bindweed’s seeds are super persistent, so it’s important to:

  • Call up your local lawn guys for bio or chemical warfare
  • Consistently remove every plant
  • Mow carefully so you don’t spread its tenacious seeds

Myrtle Spurge — Euphorbia myrsinites

This plant sports small flowers surrounded by vibrant yellow bracts— Despite their small stems and inconspicuous flowers, these forbs pose a threat to your yard and local ecosystem!

These 8 to 12-inch plants can project seeds up to 15 feet, choking out large areas of your lawn and other natural neighbors. 

The myrtle spurge produces thick sap that resembles latex, causing skin and eye irritation to most that come in contact!

If you spot blue-green leaves growing in a spiral and bright yellow bracts between March and May:

  • Hire an expert to treat your lawn and follow up for years to come
  • Pull them out by hand when the ground is moist
  • Bag or burn all flowers to prevent seeds from getting back into the soil

Dalmatian Toadflax — Linaria genistifolia ssp. dalmatica

From May until August, this plant showcases yellow flowers that resemble snapdragons— However beautiful they may seem, they steal precious resources from your other plants!

The 3-foot tall forbs have roots that can additionally reach 3 feet down into the dirt. These disruptive roots can even grow horizontally and sprout new plants in the surrounding area—soaking up the water and nutrients your lawn is thirsty for!

Locate broad, waxy, heart-shaped leaves and orange-throated yellow flowers that seem to be trying to impersonate snapdragons— Then, unmask them for what they truly are, and:

  • Ask your local yard professionals about biological solutions
  • Hand pull all weeds, ensuring you take out the whole root
  • Till repeatedly if they appear in your garden

Purple Loosestrife — Lythrum salicaria

Often mistaken for fireweed, this plant grows purply-pink flowers in vertical spikes and germinates faster than most any other native wetland species.

Flowering from July to mid-September, these woody sub-shrubs displace healthy native plants, rapidly eliminating the homes of important wildlife and thus throwing the local ecosystem off balance.

The purple loosestrife can produce up to a million seeds per plant, so even a single rootstalk can pose a huge problem!

If you see 1.5 to 8-foot stems with spikes of pink flowers with 5 to 7 petals each:

  • Hire a lawn care professional to spray your yard
  • Remove them by hand, ensuring you take the entire rootstalk
  • Remove and bag all flower stalks to prevent seed spread

Russian Knapweed — Rhaponticum repens

Commonly found near the Jordan River, this forb produces spiky purples flowers in clusters of 2 to 5. It not only threatens the survival of other plants but is also highly toxic to horses.

Blooming bright purple flowers that stand out against the crowd mid-summer, the Russian knapweed’s prominent bracts and leaves are dangerously spiky. 

If you happen upon large, irregularly-lobed leaves with sharp yellow spikes and a coating that looks like cotton candy, it’s time to take them down!

This thistle-like intruder can reach up to 12 feet tall— To prevent it from spreading its seeds and cultivating a larger tribe:

  • Sever each root below the surface of the dirt
  • Mow carefully to prevent seed propagation
  • Bag all plant pieces to stop seeds from spreading

Protect Your Yard & Community — Professional Lawn Care Services

At Lawngevity, we aim to protect Utah’s public health and natural biodiversity with our services, all while improving the aesthetic of yards all across the Wasatch Front. 

Even the prettiest perennials can cause detrimental damage to the long-term health of your lawn— Call us today to do away with noxious weeds and support the well-being of our beautiful state!

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