Weeds are a big threat to agriculture. Iowa farmers are usually concerned about the prolific and aggressive weeds like bull thistle, common buckthorn, creeping charlie, clover, hawkweed etc.
They take preventive measures to destroy seeds that can reach nearly 500,000 on every plant. Seeds from invasive weeds can easily germinate the next blooming season again, moving from one field to another and choking out other desirable crops.
Moreover, many of these invasive weeds are resistant to various herbicides. In addition, weeds utilize the optimal opportunity to pop up in lawns in warmer weather conditions in Iowa. So when summer temperatures elevate, weed control becomes a top priority for lawn owners.
However, for the best weed control in Iowa, it’s important to be aware of the weeds you should look out for in Iowan lawns or gardens. With this in mind, this article lists some of the most common weeds invading properties, causing headaches for Iowa farmers and gardeners. So let’s dive into it!
Common Weeds of Inova Lawns
Iowa gardeners may need to take aggressive steps to eliminate weeds. Of course, your aim should also be to reduce the seeds likely to germinate again the rapidly growing poisonous weed species in the next spring. But it’s foremost necessary to identify the weeds of Iowa and take quick steps to eradicate them. And this article will help you with it.
1. Bull Thistle
|Spear thistle, Common thistle, Lance-leaved thistle, Plume thistle.
This widespread biennial thistle can colonize large areas, including pastures, hay fields, woodlands, and ditch banks. Bull thistle loves open, sunny areas to sprout, but this weed can even thrive in various conditions, from dry to moist soils.
Within a two-year life cycle, bull thistle starts flowering and produces seeds in the second year. Although short-lived on the soil, their seeds can survive despite being buried for several years. However, seeds usually germinate during the fall and spring.
Bull thistle has oval-shaped cotyledons with broader apex. Young plants also have early oval leaves with a spine-like fringe. However, the second true leaves feature dense white hairs on the upper surface and are dark green. The following year, longer leaves appear with spine-like lobes.
Moreover, young leaves emerge as basal rosettes. You will see lance-shaped, deeply lobed, and alternate leaves. On the other hand, older leaves show apparent stiff spines on the edges with soft white hairs on the lower surface and stiff hairs above.
A mature bull thistle develops erect and branched stems that can grow over 5ft in height and an extensive taproot system. The leaves extend to the stem, appearing as winged. However, bull thistle starts producing flowers in June and continues till October.
Flowers emerge as single heads at the branch ends in purple to deep pink, featuring spines at the flower base. On the other hand, seeds flaunt a feathery structure that helps in dispersal, and each flower can harvest up to 300 seeds.
And fascinatingly, this weed reproduces only by seeds. Thus, preventing the plant from seeding and dispersing the seeds are the key to stopping new infestations.
Make sure not to leave cut flower stems on the soil surface, as they can sprout again.
2. Common Buckthorn
|European buckthorn, European waythorn, and Hart’s thorn.
Common buckthorn is known to be a highly adaptable and tough weed species that can thrive in different soil conditions, from fully sunny areas to shady and alkaline soils. Leaves start to fall in the early spring and again appear during the fall. Buckthorn lends a competitive advantage over native bushy plants, especially after they mature. Eventually, it can decrease overall plant diversity.
And once established, buckthorn entirely inhabits wooded areas. This plant prolifically produces small, blue-black fruits that birds consume and then spread the seeds through their droppings. Thus, buckthorn tends to infest more in fencerows, windbreaks, or hedges.
However, they can infest any lawn, garden, or properties that receive no or little care. Buckthorn seeds sprout in late summer; interestingly, many seeds can stay asleep in the soil for many years.
This tall, understory shrub or small tree can reach up to 25 feet in height. One to several stems emerge from the base, branching towards the crown. You will find twigs with thorns, usually near the tips. The bark is gray to brown, peels with age, and is dotted with light-colored lenticels. Moreover, the inner bark is orange.
Leaves are oval, opposite to sub-opposite, and dark green in color. They are even shiny and smooth. You will find small teeth along the edges, and veins bend from the base towards leaf tips. Small, four-petaled, and green-yellow flowers grow in clusters at leaf axils between May and June.
Fruits appear as pea-sized, round, and blackberries on female plants. Moreover, they are persistent through winter. Another characteristic feature is the extensive fibrous root system.
Hand-pulling and digging small plants or seedlings are effective ways to control buckthorns. However, the foliar spray might be the best defense against large populations.
3. Creeping Charlie
|Ground ivy, Creeping jenny, Gill-on-the-ground, Catsfoot, Tunhoof, Alehoof, Run-away-robin, and Feld balm.
Creeping Charlie is an evergreen, perennial and aromatic creeper that belongs to the mint family. This herbaceous plant spreads by creeping stems (stolons) and by seed. Creeping Charlie is also known as ‘ground ivy’ because of their growth appearance and patterns.
They cover lawns or gardens like a mat and continue to outspread over the lawn surface via nodes that produce roots when coming in contact with the soil. Creeping Charlie is the gardener’s nemesis as they become harder to remove once well-established.
You can easily spot this weed by its growth pattern. Creeping Charlie grows near the ground, forming a mat-like ground cover. The leaves are kidney-shaped and shiny green with scalloped margins. They have long stems with nodes where the leaves grow. Roots grow from the nodes when in contact with the soil.
Moreover, you will find short, sparse hairs on the leaf surface. Creeping Charlie is characterized by rapid growth after they stop flowering. While they belong to the mint family, Creeping Charlie has square stems. Flowers bloom in early March, growing in three clusters between the petiole and stem. They are purplish to blue and nearly 1cm long.
Creeping Charlie is characterized by five-petaled flowers that are fused into a tube or cup. Each flower emerges in axillary whorls, usually one-sided, and bears four seeds. Although they appear as a ground cover, Creeping Charlie can extend up to 8 feet in height.
This plant loves to grow in moist, damp areas, including shady locations and woodland margins. It can easily intrude on home lawns from roadsides or disturbed sites and quickly choke out the desirable turfgrass. Well, the primary line of defense against Creeping Charlie is maintaining a healthy and thick lawn with good horticultural practices.
|Broad-leaved clover, Purple clover, and Red clover.
This is another perennial weed typically found in the Iowa region. Clover covers meadows, lawns, and fields, dangling colorful flower heads. The flowers captivate bumblebees and honeybees, which further helps in pollination.
However, clovers are usually of three types – red clover, white clover, and alsike clover.
White clovers are the shortest of the three clover species. They can usually be 4 to 10 inches tall. Upon close attention, you will see creeps along the soil surface. The flowers are white with a pale-pink tinge. Interestingly, older flowers become brown and start to droop.
In addition, they have three leaflets, and each leaf features a light ‘V’ mark on it. In fact, all three clovers come with three leaflets. However, white clovers have oval-shaped leaves.
Red clovers can grow up to 16 inches and exhibit bright pink or purple flowers on rounded flower heads. Besides, their stems are covered with tiny hairs (trichomes). Leaves are compound and feature three oval leaflets with a similar ‘V’ mark as on white clover.
On the other hand, you can identify clover types by their oval-shaped, finely-toothed leaflets. However, they don’t have the unique V-shaped pattern seen in white and red clovers. Flowers can be white or pink. And flowers of all clover types become brown seed heads while they age.
Post-emergent herbicide treatments during the fall or spring can help to eradicate this weed from the roots.
|Golden lungwort, Rattlesnake weed, Mouse-ear, Devil’s paintbrush, Narrow-leaved hawkweed, and Shaggy orange
Hawkweed is a fibrous-rooted perennial plant with erect stems and characterizing dandelion-like flower heads appearing in clusters. Hawkweed needs to be controlled as this highly invasive plant can spread over large areas. This weedy plant typically grows in soils that are well-drained, coarse-textured, and low in nutrients.
Daisy-like flowers characterize these small herbs. They feature hairy green leaves of 150mm, appearing in a rosette close to the ground. Moreover, hawkweed stems are covered with stiff, short bristly hairs and contain a milky sap.
There are three hawkweed species – Orange hawkweed, King devil hawkweed, and Mouse-ear hawkweed.
Mouse-ear hawkweed can be identified by yellow flowers with square-ended petals that are 30mm across. Each stem consists of a solitary flower.
The King devil hawkweed even blooms yellow flowers with square-ended petals 20mm across. In addition, their flowers appear in clusters of nearly 25 flower heads on each stem.
On the other hand, orange hawkweed gives rise to vibrant orange flowers that feature square-ended petals about 15mm across. Moreover, flowers emerge in clusters of 5 to 30 flower heads on each stem.
Selective herbicides will be successful in managing hawkweed as they will let the grass stay in place. In addition, the herbicide will reduce the hawkweed seeds’ germination in the soil and control re-germination by the weed.
|Henbit deadnettle, Giraffehead, Common henbit.
Henbit is a cool-season annual weed of the mint family. But unlike many other plants in this family, henbit doesn’t emit a distinctive or strong odor. They are usually very competitive in newly seeded landscapes.
Seeds help in reproducing henbit. They sprout during the late summer or fall. However, henbit remains dormant throughout the winter. Flowers bloom in early summer or spring and later die off. Each henbit plant can bear more than 2000 seeds under suitable growing conditions.
This winter, the annual weed expands from 10 to 30cm in height. Fine hairs sparsely cover this edible plant germinating from a shallow taproot with fine branches. Henbit exhibits several weak stems emerging from the plant base. However, the stems can be erect or grow closer to the ground.
Henbit has square and green stems that often turn purple as they age. They reproduce completely by seed; each plant can bear up to 2,000 or more seeds. Fascinatingly, this weed can even spread through roots on lower stems touching the ground.
Small, dark pink flowers appear in rings on the upper leaf axils. Open flowers look like orchids and have white faces with dark red spots. In addition, every flower bears a four-seeded fruit.
Leaves appear in opposite pairs. The lower leaf pairs occur farther from each other than the upper leaf pairs. Moreover, henbit has heart-shaped or round leaves, up to 1.9cm long, and rounded teeth on the margins. The upper leaf surface has recessed veins that look almost wrinkled.
Henbit is a wild edible plant that prefers dry, light, cultivated soils. However, they grow best in shady areas. Unfortunately, you may only notice henbit once it produces roots and becomes established. It can choke out the desired turfgrass in your yard and compete with them for essential minerals and nutrients.
It takes time and patience to develop and maintain a lush lawn in Iowa, depending on the soil types, climates, and variety of grasses that grow here. You must ensure that your grasses get enough fertilizers throughout the germinating season.
Nevertheless, to maintain a healthy lawn, it’s essential to identify the common weeds that can invade your Iowa property anytime. So this article has hopefully helped you in it. Spot the weeds now and eliminate them in no time.