10 Common Weeds Found in New Hampshire (Identify them with pictures)

Along with assessing the association between climate and crop yield, gardeners aim to understand the relationship between climate and garden weeds. Garden weeds are tough enough to live in practically any climate and temperature.

Weeds, the doggedly persistent inhabitants of the botanical world, are an inevitable nuisance for every gardener.

With an average daily temperature of 15 degrees Celsius, New Hampshire is the coldest state in the United States. However, the climate is highly variable here, even daily. This region is classified as USDA zones 3b, 4a, 4b, 5a, 5b, and 6a, with cold, lengthy winters and brief and cool summers.

The sections below are dedicated to exploring the different garden weeds found across New Hampshire. Remember, these pesky plants can occur anywhere and, if not controlled, will create havoc on the spot they pop up.

Garden Weeds that Create a Nuisance in New Hampshire

There are literally thousands of different types of garden weeds. They are a tough, robust, and vexing plant that cannot be avoided entirely. However, the first step in dealing with garden weeds is correctly identifying them.

Identifying common garden weeds is not difficult for experienced gardeners. However, individuals who are a novice in this field know significantly less. So, here’s a list of the most common garden weeds found in New Hampshire homes.

1. White Clover

White Clover
Identifying TraitsWhite flower heads with pointy petals, three oval-shaped leaflets

White clover is one of the most frequent garden weeds in New Hampshire. However, it goes unseen until late spring, when the plant produces white blossoms that lure bees. 

White clovers are common in lawns with evenly moist soil. This is a tough garden weed that doesn’t require much attention.

White clovers come with a warning: they spread quickly and fiercely and are classified as invasive in the United States. So, even if it has the potential to fix nitrogen, cultivate them if you don’t mind them taking over your property. 

Nevertheless, if you wish to limit their spread, remove the source of moisture in your lawn and grow thick healthy vegetation. White clovers cannot tolerate dry soil.

Aside from the common white clover, there are three other kinds of this weed.

  • Micro clover
  • Atropurpureum
  • Dragon’s Blood

2. Dandelion

Identifying TraitsLong cylindrical stems, flower heads with golden rays, and puffy white seed heads
TypeBroadleaf perennial

Dandelions are an unmistakable indicator that spring is on its way. In other words, dandelions herald the arrival of spring. Their bright yellow blossoms will commonly appear on your yard, roadways, and sidewalks. 

Unfortunately, although dandelions provide a lovely floral show, they are one of New Hampshire’s most common invasive weeds. Dandelions are native throughout the Northern Hemisphere under USDA Zone 3.

Dandelion is a strong invader and disperser of its profuse seeds. Therefore, herbicides are thought to be the most effective way to control dandelions. But the difficulty is that this weed is resistant to most herbicides. So, if the infestation is severe, we recommend contacting an expert.

3. Quackgrass

Quackgrass weed
Identifying TraitsGrass-like appearance with long pointed leaves, erect stems, and flower spikes
TypePerennial grass-like

Quackgrass is a noxious garden weed that is prohibited in New Hampshire. It means that local nurseries’ sale of quackgrass seeds is forbidden under local legislation.

Quackgrass is most commonly found in various soil types in damp meadows, croplands, urban settings, and disturbed areas. This is a tough weed, and uprooting it manually may not be easy once it has established its root system.

Pulling quackgrass is not a good idea, and your chances of success are slim. This weed is the last thing you want to see growing on your lawn. This is not only because quackgrass is invasive but also because it is allelopathic. Its roots produce toxins that hinder adjacent plants from growing.

Pre-emergence herbicide spraying is one of the most effective strategies to keep quackgrass weed from colonizing your property. However, using a non-selective herbicide on quackgrass will only succeed.

4. Canada Thistle

Canada Thistle
Identifying TraitsCreeping growth with purple and white flowers and spikey stems that can grow up to 4 feet

The creeping perennial Canada thistle can be found anywhere, including croplands, pastures, roadsides, lawns, and non-crop places. Canada thistle, one of the hardiest garden weeds, is a noxious species in New Hampshire.

Although it is illegal to sell its seeds in New Hampshire, you may wish to keep this plant on your lawn if it grows there. We say this because Canada thistle is an important food for garden and agricultural birds and a food source for humans.

But, above all, Canada thistle is an invasive plant that spreads quickly. A lawn overgrown by this weed appears too unkempt and dangerous to walk on. If you step on the spikey stems of this weed, it can be extremely painful.

Furthermore, if it spreads uncontrollably, it has the potential to remove beneficial flora and lower crop yields. So, while the invasion is still in its early stages, try to restrict the spread of this weed by spraying a strong weed controller.

5. Crabgrass

Identifying TraitsCompound long leaves radiating from a central point look like grass and produce white flower heads
TypeAnnual, grass-like

Crabgrass is one of the most difficult grass-like weeds to control. Crabgrass, a restricted weed in New Hampshire, is most visible in the late spring on any bare area with access to water and sunlight.

This plant grows throughout the summer, becoming unkempt when it is ready to set seeds (in late summer). Because it is an annual weed, you may believe it will not return the next season.

However, you would be completely incorrect in thinking this way. The seeds would remain dormant during the winter and grow the following spring.

However, having crabgrass on your lawn is not all that horrible. This grass weed will not suffocate your desired lawn grasses. However, it looks horrible in the late summer, making the lawn messy.

So, if you want to get rid of crabgrass, the best time to uproot them is in the spring, when the plants are most vulnerable. Following that, you can use an organic fertilizer to promote the growth of your preferred lawn grass.

6. Nutsedge

Identifying Traits3-ranked arrangement of leaves pale yellow leaves

The yellowish green nutsedge, a restricted noxious weed in New Hampshire, is a difficult plant to eradicate. This weed is most usually found on summer lawns. Nutsedge has a deep rhizome that can send hundreds of shoots within a single growing season, producing over 1,000 new roots. Sounds scary, right?

This plant is difficult to control because of its long root systems and great tolerance. Nutsedge is resistant to external stressors and can even infiltrate mulch. So, how do you keep nutsedge under control?

You can till when the initial shoots appear in late spring. However, if the infestation is severe, repeated tilling may be required. Grow a broad blanket of summer crops after tillage to minimize nutsedge regeneration.

You May Also Read: Weeds in Florida: Types, Identification, and Many More

7. Moneywort

Identifying TraitsLow growth, opposite growing round leaves, and yellow flowers
TypeBroadleaf perennial

Moneywort is a freshwater tropical aquarium plant species. It is a creeping plant that grows along stones and puddles in the wild and is frequently confused with Creeping Jenny. This weed is typically found in creeks, riverbeds, canals, and along roadsides.

Moneywort’s laterally branching stems can quickly develop a thick mat in lawns. However, it can be controlled with suitable cultural measures. Focus on growing dense grass cover to keep this weed at bay.

Manual removal, by hand pulling, is also possible, but you risk spreading more seeds across your garden.

8. Mallow

Identifying TraitsBroad, flattened, circular-to-kidney-shaped leaves with hairy stems that lay low near the soil surface.
TypeWinter annual

Mallow, also known as Malva neglecta, is a broadleaf weed that grows in the winter. However, if favorable climatic conditions continue, it may change into a biannual weed, meaning it will have two growing seasons.

Mallow grows in various settings, including unkempt turfgrass lawns, gardens, and outdoor areas. This weed’s capacity to endure various seasons and soil conditions makes it a hardy and widespread type throughout New Hampshire.

Mallow spreads largely by seeds, although it can also proliferate through fractured stems that come into touch with the soil. It is easy to confuse it with ground ivy due to its near likeness.

However, examine the leaves carefully to identify the differences. Ground ivy leaves, for example, are opposite on the main stem, whereas mallow leaves are somewhat hairy on both sides. That being said, pre-emergence herbicide applications in the spring and fall are most successful in reducing the spread of mallow.

9. Poison Ivy

Poison Ivy
Identifying TraitsGlossy trios of leaflets and  small clusters of flowers yellow-green flowers and berry-like fruits

Poison ivy is a dangerous garden weed. But what makes it poisonous? The production of a toxic phenol called  Urushiol. Poison ivy is most commonly found on the sides of roads, lakes, lawns, and riverbanks. 

This is a resilient plant that can grow in both shade and sunlight. As a result, it can be found practically everywhere in New Hampshire and its surrounding areas.

It does not require its natural habitat to thrive. Poison ivy, on the other hand, can spread and adapt to any environment. It is an annual weed that remains active into the fall. 

Despite being deadly, its fruits provide food for wildlife. Animals are drawn to poison ivy fruits to devour them and excrete seeds, assisting the plant’s proliferation and survival.

One of this plant’s distinguishing features is its lovely reddish green foliage, which turns into a stunning burned orange as fall approaches.

Although they are attractive, if you come into contact with them, expect severe itching, red blisters, and rashes.

10. Common Ragweed

Common Ragweed
Identifying TraitsCompound leaves with petioles at the base (of the lower leaves), bushy growth, and innocuous green flowers.

The common ragweed is another toxic weed on our list. This garden weed is usually found in waste areas, lawns, agricultural fields, roadsides, and vacant lots, among other places. It is one of the most prevalent weeds found in northern America. 

Ragweeds not only make your lawn seem unsightly, but they are also well-known allergies. It causes symptoms such as sneezing, itching eyes, sinusitis, etc. 

If you suffer from allergies, you must detect ragweeds and act to eliminate them before they establish deep roots.

Remember that ragweed begins to pollinate in most areas in July and reaches its peak in September. However, the most astounding fact about this weed is that if allowed to mature for the whole growing season, it may yield a stunning quantity of seeds—up to 62,000.

Mulching the places where ragweed seeds are likely to sprout is one of the most effective strategies to limit the growth of this weed on your lawn. Sunlight is required for the seeds to germinate. 

If you shut off that supply, the germination rate will be reduced. However, don’t hesitate to contact your local weed controller if you have adult ragweeds on your property.

Also Read: 13 Common Weeds in Georgia | Guide to Identify With Pictures

The Key Takeaway

So this was our take on common garden weeds found across New Hampshire. Although it is almost impossible to keep a lawn or garden free from weeds, you can always work toward eliminating them. And the first step toward weed elimination is identifying a weed as a weed.

Keeping this in mind, our list will prove to be of great help if you live in New Hampshire. However, this is not an inexhaustible list. So, if you have encountered any other weeds on your lawn, do let us know in the comment box below.

About Jennifer Igra

Growing up in Brooklyn, New York City known for it’s green gardens. Jennifer, a 30 year old gardener and green living fanatic started Igra World to share her gardening journey and increase gardening awareness among masses. Follow Igra World to improve your gardening skills.

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