Identifying Common Northern Arizona Weeds
Northern Arizona spans the south-western portion of the Colorado Plateau and all of the Transition Zone beneath. This unique region of the Southwest hosts a surprising variety of weeds, all with their own unique traits and challenges. Understanding the weeds that grow here is the first step in managing and maintaining your landscape. We created this guide to help you both understand the different weed categories and to identify specific problem weeds in your area.
Image Credit: https://commons.wikimedia.org/wiki/File:Physiographic_regions_of_Arizona.svg
Annual vs Perennial Weeds
Weeds are generally classified by their life cycle: annuals, which complete their growth in a single season, and perennials, which live for multiple years. Understanding the difference is key for dealing with them effectively, as their growth habits, reproduction, and control methods will vary depending on what kind of weed you are dealing with.
Annual Weeds
Annuals are the “sprinters” of the weed world as they germinate, grow, flower, set seed, and die all within a single growing season. They grow very fast, are opportunistic, and are usually the first plants to colonize bare soil. Because they die at the end of their growing season, they rely on seeds to persist. A single plant can produce thousands of seeds that remain viable in the soil for years creating a seed bank under the ground. Because of their annual nature, they become a recurring problem year after year.
Some examples of annual weeds in Arizona include Puncturevine, Spotted Spurge, and the infamous Tumbleweed.
Perennial Weeds
Perennial weeds are the “survivors” of the weed world. They grow strong root systems underground that allow them to come back season after season. Many will grow back even if mowed or partially pulled out, as even fragments of a root or rhizome of certain weeds remaining in the ground can regrow into a new plant. This makes them harder to completely eliminate.
Some examples of common Northern Arizona weeds that are perennials include Silverleaf Nightshade and Horehound.
Grassy Weeds vs Broadleaf Weeds vs Sedge Weeds
In addition to Annual vs Perennial, another way to classify weeds is by Grassy vs. Broadleaf vs Sedge weeds. Grassy weeds resemble turf grass in appearance with long narrow leaves that grow from nodes on the stem. Typically they grow in parallel veins. They spread fast which makes them hard to distinguish from the grass you may want in your landscape. Broadleafs on the other hand are easier to spot because they have wider leaves. They grow more upright or spread and often sprout flowers. Sedge weeds are often mistaken for grasses, but they are a different category entirely. Sedges have a solid, triangular stem and typically grow in three ranks rather than two. Their leaves are often glossy and thicker than most grasses. Knowing the difference between the three will help you better manage and prevent them growing in your landscape.
Grassy Weeds
Grassy weeds look very similar to the grass that grows in one’s yard or pasture and can make them tricky to spot before they spread. They have slender bladelike leaves that emerge one at a time from the soil. Many grassy weeds are annuals and spread quickly through seed production.
Common examples of grassy weeds include crabgrass, goosegrass and foxtail.
Broadleaf Weeds
Broadleaf weeds are usually easier to spot on your property because of their wide leaves, branching veins, and often colorful flowers. Broadleaf weeds have varied life-cycles and can be annual or perennial depending on the plant. They are hardy and spread through seeds or underground roots. Because of how they can regrow, they can be resilient to mowing or hand-pulling.
Examples of Broadleaf weeds found in Northern Arizona include: Puncturevine, Ragweed, and several varieties of Thistle
Sedge Weeds
Sedge weeds are often mistaken for grassy weeds because they have narrow leaves and grow upright, but they are a separate plant family altogether. A key difference is their solid, triangular stems. One helpful reminder is “sedges have edges.” Their leaves typically grow in groups of three and are often thicker and glossier than turf grass. Sedges commonly thrive in compacted soil or areas with poor drainage.Many sedges are perennial and spread aggressively through underground tubers or rhizomes, which makes them difficult to control with mowing alone.
Examples of sedge weeds found in Northern Arizona include: Yellow Nutsedge, Purple Nutsedge, and Green Kyllinga.
Noxious Weeds per the State of Arizona
The Arizona Department of Agriculture maintains a noxious weeds list: https://agriculture.az.gov/pestspest-control/agriculture-pests/noxious-weeds
The definitions are as follows:
Class A Noxious Weed is a “species of plant that is not known to exist or of limited distribution in the State and is a high priority pest for quarantine, control, or mitigation”.
Class B Noxious Weed is a “species of plant that is known to occur, but of limited distribution in the State and may be a high priority pest for quarantine, control or mitigation if a significant threat to a crop, commodity, or habitat is known to exist.”
Class C Noxious Weed is a “species of plant that is widespread but may be recommended for active control based on risk assessment.”
The Arizona Department of Agriculture lists the following restrictions:
“No Class A, B, or C Noxious Weed, or commodity infested or contaminated with a Class A, B, or C Noxious Weed, shall be admitted into the state unless otherwise authorized by the Associate Director.”
“The Department may quarantine and abate an area infested or contaminated with a Class A or Class B Noxious Weed if it has been determined by the Associate Director that an imminent threat to agriculture or horticulture exists.”
Invasive weeds
Finally, there are invasive weeds which are not native to the region and pose a serious challenge to the ecosystem. Where possible these plants are noted as well below.
https://www.invasivespeciesinfo.gov/subject/lists
https://dffm.az.gov/forestry-community-forestry/forest-health/invasive-plants
Without further ado, here is a breakdown on the most common Northern Arizona weeds.
Common Broadleaf Weeds of Northern Arizona
Here are some of the most common broadlead weeds you will find here in Northern Arizona.
Scotch Thistle
About: Scotch Thistle (Onopordum acanthium) is an aggressively-growing biennial weed from the sunflower family. It is an invasive plant originally from Europe and likely gets its name due to its similarity to Spear Thistle (Cirsium vulgare), the national flower of Scotland. Each plant can yield up to 40,000 seeds, many of which remain viable in the soil for up to five years. In its first year, it is spiny and gray-green growing huge rosettes and leaves up to two feet long which are covered in dense hairs and edged with spines. In its second year, Scotch Thistle bolts upward and grows winged, spiny stems topped with clusters of reddish-purple to pink flowers which bloom June through September.
Quick Facts:
Life-cycle: Biennial
Size: Up to 10 feet tall.
Russian Thistle AKA Tumbleweed
About: Russian Thistle (Kali tragus) is another name for the infamous Tumbleweed. It was originally introduced from Russia (hence the name), but can now be found across the southwest United States. It grows up to three feet tall and thrives in dry, disturbed soil and fields. It grows rounded, branching stems that turn hard and prickly as they dry, often showing distinctive red striping. It has narrow spiny-tipped leaves and small greenish flowers that make it easy to miss until late summer. When it matures, it detaches from its base and rolls along with the wind scattering 10s of thousands of seeds wherever it goes.
Quick Facts:
Other Names: Other nicknames for Russian Thistle include: Tumbleweed, Windwitch, Tumbling Thistle, and Leap the Field.
Life-cycle: Annual
Size: Up to 6 feet, but usually smaller.
Bonus Weed Facts
One single tumbleweed can produce tens of thousands of seeds each year!
Here’s our video on Tumbleweed!
Puncturevine
About: Puncturevine (Tribulus terrestris) is another weed found throughout the state of Arizona. It was brought here from southern Europe and spread rapidly through most of North America. Puncturevine can be found everywhere, but especially alongside roads, fields, and less trafficked areas. The sharp spikey seedpods are the reason for the nickname, because they can puncture tires and injure people and pets when stepped on. The plant is also toxic to livestock. It flowers from March to October with yellow flowers. The fruit is fruit flat, breaking up into 5-nutlets with strong dorsal spines. It has a pinnately compound leaf with 6 to 12 green leaflets.
Quick Facts:
Other Names: Other nicknames for Puncturevine include: Goathead, Caltrops, Bullhead, and Mexican Sandbur.
Life-cycle: Annual
Size: Up to 3 feet but usually about 12 inches
Silverleaf Nightshade
About: Silverleaf Nightshade (Solanum elaeagnifolium) is one of the native plants on our list. In Arizona it grows at elevations of roughly 1,000 to 6,000 feet and grows alongside roads, in fields, and pretty much anywhere dry or irrigated. It is a forb or subshrub that spreads by creeping rhizomes. The silvery foliage is covered in fine whitish scales, and the stems have short but very sharp spines. The leaves are oblong and grow up to 6 inches in length, and range from greenish-blue to silvery, sometimes turning yellowish, with edges that can be smooth or coarsely toothed. The plant produces purple to violet flowers arranged in raceme-like clusters, each corolla measuring 3/4 to 1 inch wide with five lobes joined at the base and prominent yellow to orange anthers. Unlike some other nightshades, the calyx does not form a paper-like covering around the fruit. The fruit itself consists of small, round, bright yellow berries that are poisonous.
Quick Facts:
Other Names: Nicknames for Silver Nightshade: Silver-leaf Nightshade, Tomato Weed, White Horse-nettle, White Nightshade, Bull Nettle, Trompillo, White Horsenettle
Life-cycle: Perennial
Size: Up to 3 feet tall.
Bonus Weed Facts
Arizona has as many as 18 species of Solanum growing here!
Spotted spurge
About: Spotted Spurge (Euphorbia maculata) is a weed that is introduced or naturalized to North America, but has spread to Europe, South America, Australia, parts of Africa, and Asia. It grows quickly and particularly likes sunny areas like garden beds, fields, near railroad tracks, cracks in sidewalks, and anywhere it can sink roots. It is considered toxic and the sap is a skin irritant. Touching it should be avoided. It has small, oblong opposite leaves, which are covered in small thin hairs, and generally have a scalloped edge. The “spotted” in its name comes from the fact that each leaf is marked with a small brown spot in the middle. The Spotted Spurge flowers in the summer with flowers that grow in clusters. The flowers are small and leaf-like with a red calyx and white to pink petals when they bloom. When they fruit, it grows small, 3-lobed fruit which is covered in soft fine hairs.
Quick Facts:
Other Names: Other nicknames for Spotted Spurge include milk purslane or spotted sandmat
Life-cycle: Annual
Size: Up to 12 inches.
Meadow Goat’s Beard
About: Meadow Goat’s Beard (Tragopogon pratensis) is a biennial flowering plant in the sunflower family that can grow up to about 30 inches tall. It produces long, narrow, grass-like leaves that are smooth and gray-green with a white midrib. As the plant matures, it develops upright stems that produce bright yellow flowers resembling small dandelions. These flowers open in the morning sunlight but often close by midday, which gives the plant its nickname “Jack-go-to-bed-at-noon.” After flowering, it forms large round seed heads similar to oversized dandelion puffballs. These fluffy seed heads allow the plant to spread easily by wind. Meadow Goat’s Beard is commonly found growing in fields, roadsides, and other disturbed landscapes.
Quick Facts:
Other Names: Jack Go to Bed at Noon, Meadow Salsify, Noonday Flower, Noonflower, Noontide, Star of Jerusalem, Yellow Goat’s Beard
Life-cycle: Biennial
Size: Up to 30 inches tall
London Rocket
About: London Rocket (Sisymbrium irio) was originally introduced to America from Europe. It can be found throughout the southwest United States, around the Great Lakes, and it can also be found in the Carolinas and Florida. It is a very aggressive weed and does particularly well after fires. The sudden and swift growth of them after the Great Fire of London in 1666 is where the nickname originates. It grows most readily in fields, irrigated areas, and desert landscapes below 4,500 feet. It flowers in early spring with pale yellow flowers in small clusters on tips of branches. The fruit is a slender round pod. The leaves are green with varied shapes. Basal leaves can reach up to 6 inches and are often lobed, while stem leaves are narrower and may attach by stalks or directly to the stem. The foliage has a bluish tint and is mostly smooth.
Quick Facts:
Other Names: Nicknames for London Rocket include Rocket Mustard, (Spanish: Mostaza, Pamita)
Life cycle: Annual
Size: 2 feet or more.
Wild Mustard
About: Wild Mustard (Sinapis arvensis) is an annual winter or summer weed of the mustard family. It begins as a basal rosette of hairy, lobed leaves with prominent veins. As it matures, it develops upright stems that can grow up to about three feet tall, often branching near the top. The plant produces clusters of bright yellow, four-petaled flowers, followed by long, narrow seed pods containing dark round seeds, which allow it to reproduce and spread quickly. Wild Mustard can be found almost all over Arizona, but it particularly favors pastures, fields, roadsides, cultivated places, and disturbed ground.
Quick Facts:
Other Names: Field Mustard, Charlock, or Charlock Mustard
Life cycle: Annual
Size: 12-36 inches (occasionally ~40 inches)
Musk Mustard
About: Musk Mustard (Chorispora tenella) is an annual flowering plant in the mustard family that can grow up to about 20 inches tall. Native to parts of Eurasia, it has spread throughout many temperate regions as an introduced weed. The plant produces slender upright stems with narrow, slightly wavy-edged leaves that grow alternately along the stem. In spring, it develops clusters of small four-petaled flowers that range from lavender to pale purple, sometimes giving heavily infested fields a faint purple color. After flowering, the plant forms long narrow seed pods containing small reddish-brown seeds. These pods eventually split open, allowing the seeds to spread quickly
Quick Facts:
Other Names: Purple mustard, blue mustard, musk mustard, crossflower
Life-cycle: Annual
Size: Up to 20 inches tall (occasionally taller)
Tansy Mustard
About: Tansy mustard (Descurainia pinnata) is an annual flowering plant in the mustard family that commonly grows between 6 and 24 inches tall. Native to western North America, it is widely found across desert and semi-arid regions where it often appears as a winter or early spring weed. The plant produces thin branching stems with finely divided, feathery leaves that give it a soft, fern-like appearance. In spring, it develops small clusters of tiny yellow four-petaled flowers at the ends of upright stems. After flowering, the plant forms numerous slender seed pods that stand upright along the stems. These pods eventually dry and split open, releasing many tiny seeds that allow the plant to spread easily.
Quick Facts:
Other Names: Western tansy mustard, Pinnate tansy mustard
Life-cycle: Annual
Size: Typically 6-24 inches tall (sometimes taller)
Horehound
About: Common horehound (marrubium vulgare) is a flowering weed in the mint family (Lamiaceae). It is native to Europe, Africa, and parts of Asia, but can be found on all continents now. It has grey leaves, which are up to 2 inches long with a crinkly surface covered in downy hairs. It has white flowers which grow in clusters towards the top part of the main stem. It has seen use in food and medicines as far back as the 1st century BC, including use as a livestock medicine. Horehound likes to grow in disturbed areas, especially where animals have grazed, even though most livestock avoid it.
Quick Facts:
Other Names: Horehound also goes by White Horehound.
Life-cycle: Perennial
Size: 10-18 inches tall
Cheeseweed Mallow
About: Cheeseweed Mallow (Malva parviflora) is a low-growing weed that can spread along the ground or grow upright, typically reaching 1 to 3 feet tall. It has round, slightly lobed leaves with shallow, toothed edges, often forming a dense patch as it grows from a taproot that helps it tolerate dry conditions. The plant produces small white to pale pink flowers at the base of the leaf stalks, followed by distinctive round seed clusters that resemble tiny wheels of cheese, which give the plant its name.
Quick Facts:
Other Names: Cheeseweed, Little mallow, Small-flowered mallow, Egyptian mallow.
Life-cycle: Annual (sometimes short-lived biennial)
Size: Up to 3 feet tall
Common Sowthistle
About: Common Sowthistle (Sonchus oleraceus) is a part of the sunflower family. It was possibly introduced here from Europe. It can now be found throughout almost the entirety of North America. It’s an annual (in some places biennial) plant which can grow up to 3 feet tall or more.
It is a leafy weed with tall, hollow stems that leak a white, milky sap if they’re broken. The leaves grow one after another up the stem and can look a bit different depending on where they are. Some are long and narrow, others broader, but many have spiny, deeply cut edges and small “wings” at the base. In spring and summer it sends up clusters of bright yellow flowers about the size of a dime to a quarter, which look a lot like dandelions and usually open in the morning.
After blooming, the flowers turn into fluffy seed heads with white hairs that catch the wind, helping the plant spread to new spots. It flowers from March/April to September/October normally but in the southern states it can be all year round. It is not picky in terms of growing location and can be found pretty much anywhere in Arizona.
Quick Facts:
Other Names: Nicknames for Common Sowthistle include Common Cow Thistle, Hare’s Thistle, Milk Thistle, Laiteron, Hare’s Colwort.
Life-cycle: Annual
Size: About 1 – 3 feet tall
California Burclover
About: California burclover (Medicago polymorpha) is an annual plant in the legume family that commonly grows low to the ground, forming spreading mats across soil and gravel landscapes. Native to the Mediterranean region, it has become widely naturalized throughout many parts of North America and is a common winter weed in dry climates like Arizona. The plant produces creeping stems covered with small clover-like leaves, each leaf made up of three rounded leaflets with slightly toothed edges. In spring, California burclover develops tiny yellow pea-like flowers that can grow singly or in small clusters. After flowering, the plant forms distinctive spiral-shaped seed pods covered with small hooked spines. These burs easily attach to clothing, animal fur, and equipment, helping the seeds spread to new locations. California burclover commonly appears in lawns, gravel yards, roadsides, and disturbed soils.
Quick Facts:
Other Names: Bur clover, burr medic, toothed medic
Life-cycle: Annual
Size: Typically 4-12 inches tall but can spread outward several feet across the ground
Common stork’s-bill
About: Common stork’s-bill (Erodium cicutarium) is a herbaceous, flowering annual plant (sometimes biennial in warmer climates). It was brought to the Americas in the 1700s, but has since been naturalized, especially in the southwestern United States. It grows in rosettes flat and close to the ground. It features a deep taproot that allows it to survive dry climates like here in Northern Arizona.
The reddish or green stems can sprawl up to 2 feet long with hairs along it that grow denser towards the top. This plant has long seed-pods that are shaped like a stork’s bill (hence the name). When ripe these seed pods break open spreading seeds into the air. Each flower has five rounded petals, typically pink to violet with darker veining, and blooms on slender stalks rising above the low-growing rosette.
Quick Facts:
Other Names: Nicknames for Redstem Filaree, Redstem Stork’s Bill or Pinweed.
Life-cycle: Annual (Biennial in warmer climates)
Size: 10-18 inches tall
Common Groundsel
About: Common Groundsel (Senecio vulgaris) is a fast-growing annual weed that typically reaches 6 to 16 inches tall with upright, branching stems. Its leaves grow alternately along the stem and are deeply lobed with toothed edges. The plant produces small yellow flower heads that are mostly hidden by green bracts. This gives them a cylindrical appearance rather than the typical open daisy shape we might expect. After flowering, it forms fluffy white seed heads similar to tiny dandelions, which allow the plant to spread quickly by wind-blown seeds. Common Groundsel is unwelcome for a handful of reasons. First, it is listed as a noxious weed in some parts of the United States. Second, it contains compounds that can cause liver damage in livestock if consumed. Third, it can act as a host for a fungus that causes black root rot in many more desirable plants like peas, carrots, and tomatoes.
Quick Facts:
Other Names: Groundsel, Old-man-in-the-spring, Simson, Birdseed
Life-cycle: Annual
Size: Up to 16 inches tall.
Buffalobur Nightshade
About: Buffalobur Nightshade (Solanum rostratum) is an annual plant in the nightshade family, typically growing about 1 to 2 feet tall. It has sharp yellow prickles that cover its stems and leaves, as well as the star-shaped hairs that give it a slightly rough look. The green leaves are deeply lobed and can range from 1 to 6 inches long, with broad, irregular segments. In summer, clusters of bright yellow flowers appear, each about an inch wide. The flower’s five anthers aren’t all alike, as four are straight and one is curved, along with a gently curved style in the center. After blooming, the plant produces small, dry berries that remain enclosed by the papery calyx. It flowers from June to August in Arizona and thrives in plains, fields, roadsides, and any disturbed ground. This weed is highly toxic to both livestock and humans.
Quick Facts:
Other Names: Nicknames for Buffalobur Nightshade include Colorado Bur, Horned Nightshade, Kansas Thistle, Mexican Thistle, Texas Thistle
Life-cycle: Annual
Size: typically 1-2 feet tall
Common Mullein
About: Common Mullein (Verbascum thapsus) is part of the Figwort Family. It was introduced here to America from Europe, North Africa, and Asia. It usually lives for two years and can grow six feet tall or more. In its first year, it forms a low rosette of big, soft, gray-green leaves that feel almost like felt. During its second year a single tall flower stalk shoots up, lined with fuzzy, narrow leaves that run partway down the stem. In summer the stalk is topped with a thick spike of bright yellow flowers.
Each individual bloom lasts only a short time, but new ones keep opening, so the spike stays colorful for weeks. After flowering, the plant forms small, hairy seed capsules that can remain standing through winter, giving it a distinctive silhouette even when the flowers are gone. It flowers from June to September in Arizona and California. It particularly does well in waste ground, disturbed areas, and roadsides.
Quick Facts:
Other Names: Nicknames for Common Mullein include Big Taper, Flannel Mullein, Flannel Plant, Velvet Plant, Woolly Mullein
Life-cycle: Biennial
Size: Up to 6 feet or more.
Bonus Weed Facts
Thanks to Michigan State University’s Beal Seed Experiment, we now know that Mullein seeds can lie dormant and viable in the ground for over 140 years!
Henbit Dead-Nettle
About: Henbit Dead-Nettle (Lamium amplexicaule) is a low-growing winter annual that typically grows 4 to 10 inches tall with soft, often slightly hairy square stems. It has rounded, scalloped leaves that grow opposite each other along the stem, with the upper leaves clasping the stem. In late winter and early spring, the plant produces small pink to purple tubular flowers in clusters near the top of the plant. Henbit spreads by producing hundreds of seeds, allowing it to quickly take over lawns, gardens, and disturbed soils.
Quick Facts:
Other Names: Henbit, Henbit deadnettle.
Life-cycle: Annual
Size: 4-12 inches, but occasionally taller in ideal conditions.
Common Purslane
About: Common Purslane (Portulaca oleracea) is an annual plant in the purslane family that grows low to the ground, usually spreading outward up to about 20 inches. Its smooth, reddish-green stems are succulent and prostrate, with tiny hairs found at the stem nodes. The fleshy green leaves are also succulent, flattened, and range up to about 1 inch long, typically shaped like small spoons (obovate to spathulate). Small yellow flowers appear singly or in clusters of two to five at the tips of the stems. Each flower has green or sometimes reddish sepals, five yellow petals, and 5 to 20 stamens. After flowering, the plant forms a capsule-shaped fruit that releases black or dark brown, flattened seeds. It flowers roughly from mid-summer through fall.
Since being introduced it has spread throughout North and Central America.
Quick Facts:
Other Names: Nicknames for Common Purslane include Akulikuli-kula, Duckweed, Garden Purslane, Little Hogweed,, Pursley, Verdolaga, Wild Portulaca
Life-cycle: Annual
Size: Up to about 20 inches
Shepherd’s Purse
About: Shepherd’s Purse (Capsella bursa-pastoris) is an annual weed in the mustard family found throughout Arizona and much of the United States. It can be found in fields, gardens, lawns, roadsides, and other disturbed landscapes. The plant begins as a low rosette of lobed leaves close to the ground. From this base, a slender upright stem grows upward, usually reaching between 4 and 20 inches tall. Small white flowers appear in clusters along the stem and bloom throughout much of the growing season. Shepherd’s Purse is easily recognized by its distinctive seed pods. These pods are small, flat, and triangular to heart-shaped, resembling a tiny purse or pouch, which is where we get the name for the weed. Each pod contains numerous tiny seeds that allow the plant to spread quickly.
Quick Facts:
Other Names: Shepherd’s Purse, Lady’s Purse
Life-cycle: Annual (sometimes biennial)
Size: Typically 4-20 inches tall
Ashen Milkvetch
About: Ashen milkvetch (Astragalus tephrodes) is a native perennial plant in the legume family commonly found in the southwestern United States, but especially throughout northern Arizona. This low-growing herb typically forms a spreading, ground-hugging plant with short, prostrate stems covered in fine grayish hairs. This gives it a soft, ashen or silvery appearance. Its leaves are pinnately compound, made up of many small leaflets that contribute to its feathery look. From spring into early summer, Ashen milkvetch produces clusters of relatively large, showy flowers that range from purple to pink-purple. After flowering, the plant develops distinctive seed pods with ridged surfaces. It commonly grows in rocky soils, dry slopes, and open pine forest areas at mid to high elevations.
Quick Facts:
Other Names: Ashen Milk-Vetch (alternate spelling)
Life-cycle: Perennial
Size: Up to 20 inches
Bonus Weed Facts
There are over 3,000 species of Milkvetch (Astralagus)!
Morning-Glory
About: Several species of morning-glory grow in Arizona all of which are members of the Convolvulaceae (morning-glory) family. These native or regionally occurring plants are generally annual or perennial vines with slender to twining stems, heart to lobed-shaped leaves, and funnel-shaped flowers. Their blooms typically open in the morning and close by afternoon. Their height can vary depending on what plants they are able to wind their vines around.
Here is the rundown on the various varieties that we find here in Arizona. These morning-glory species share common traits (twining stems, morning-blooming funnel flowers, and capsule fruits) but each has distinctive leaf shapes and flower colors that help with identification.
Here are some of the more common varieties of Morning Glory we have here:
Local Morning-glory varieties:
Canyon Morning-glory (Ipomoea barbatisepala) is an annual plant with 5-7 lobed leaves. They have either purplish-pink or white flowers with short stalks which flower from July–September (sometimes into October).
Fun Fact: This particular variety is not as common across the US as the others and pretty much only grows in Arizona, New Mexico, and some of Texas.
Purple Morning-glory (Ipomoea capillacea) is an annual that prefers oak woodlands and ponderosa pine areas. It has green sessile linear leaves and pretty purple flowers that grow solitarily off of the branches. It flowers from July to September and likes elevations of 5-6,000 feet.
Crestrib Morning-glory (Ipomoea costellata) is an annual plant that has green palmately-lobed leaves typically with three lobes. The flowers range from a pale-pink to lavender and grow solitarily on long pedicels. They flower from July to October and grow at elevations of between 3,500 and 6,000 feet. They like dry plains, mesas, and pine-forests.
Trans-Pecos Morning-glory (Ipomoea cristulata) are also called Scarlet Creeper and Scarlet Morning-glory. They are an annual plant that have palmately lobed (3–5 lobes) leaves. The flowers are red, ranging from scarlet to reddish orange. They flower from June–September, occasionally into October, and tend to grow at elevations of 2,500 and 9,000 feet.
Ivyleaf Morning-glory (Ipomoea hederacea) is also known as Entireleaf Morningglory, and Mexican Morningglory. It is an annual plant with leaves that are variable with 3-5 lobes. It has blue to light-blue flowers, which flower from July to November. It grows best at altitudes of 1,000 to 5,000 and tends to thrive in fields and along roadsides.
Pinkthroat Morning-glory (Ipomoea longifolia) is perennial plant also known as Longleaf Morning Glory. It has elongate green leaves and white flowers that have a deep pink throat. They flower from July to August and tend to grow at elevations of 4,000 to 6,000 feet.
Tripleleaf Morning-glory (Ipomoea ternifolia) is an annual plant which has purple flowers that flower from August to September. It thrives at 4,000 to 7,000 feet and prefers desert scrub and grassland.
Common Grassy Weeds of Northern Arizona
Here are some of the most common grassy weeds you will find here in Northern Arizona.
Cheatgrass
About: Cheatgrass (Bromus tectorum) is an invasive annual grass found throughout Arizona and much of the western United States. Originally brought from Europe and Asia in the 1800s, it spread rapidly across rangelands, roadsides, and open desert areas. Cheatgrass is especially common in disturbed soils and overgrazed fields. It germinates early in the season, grows quickly, and then dries out by late spring or early summer. When dry, it becomes highly flammable, contributing to increased wildfire risk. The plant produces soft green seed heads that turn reddish-purple and then tan as they mature. Its barbed seeds can cling to clothing or animal fur, helping it spread easily.
Quick Facts:
Other Names: Downy brome, June grass, Military grass
Life-cycle: Annual
Size: Up to about 6 to 35 inches
Annual Bluegrass
About: Annual Bluegrass (Poa annua) also known as Annual Meadow-Grass is a common low-growing turfgrass which thrives in temperate climates like Arizona. Annual Bluegrass has a shallow fibrous root system with a stem that grows 4 to 12 inches tall. The leaves are mostly smooth on the top and bottom, but are slightly rough along the edges. In some locations it can flower the entire year. Typically though it flowers late winter through spring and can flower very early compared to other grasses. The seeds are deposited repeatedly throughout its growing season.
Quick Facts:
Other Names: Annual Meadow Grass, Poa Annua
Life-cycle: Annual
Size: 4–12 inches tall