Hawaii weeds (20 of the most common)

Invasive weeds are a significant problem in Hawaii, threatening the state’s native flora and fauna, as well as human health and safety. These weeds can be found in various habitats, including forests, fields, and gardens. Effective weed management strategies are essential to prevent the spread of invasive species and protect Hawaii’s natural resources. 

These strategies may include physical removal, chemical control, and preventative measures such as proper landscaping and plant selection. By understanding the impact of invasive weeds and implementing effective management practices, we can help to preserve Hawaii’s unique and fragile ecosystems.

noxious weeds of hawaii

Table of Contents

hawaii weeds

Name of weed Family
Kahili Ginger Zingiberaceae
Kikuyu Grass Poaceae
Guinea Grass Poacea
Hilo Grass Poaceae
Fountain Grass Poaceae
Mexican Clover Rubiaceae
Lovegrass Poaceae
Blackberry Nightshade Solanaceae
Fireweed Asteraceae
Australian Tree Fern Cyatheaceae
Japanese Knotweed Polygonaceae
Lantana Verbenaceae
Brazilian Pepper Anacardiaceae
Christmas Berry Anacardiaceae
Elephant Grass Poaceae
Broadleaf Dock Polygonaceae
Bindweed Convolvulaceae
Purslane Portulacaceae
Wild Radish Brassicaceae
Yellow Woodsorrel Oxalidaceae

Kahili Ginger (Hedychium gardnerianum)

Kahili Ginger, also known as Hedychium gardnerianum, is a perennial weed that belongs to the Zingiberaceae family. It is native to the Himalayas but has been introduced to Hawaii, where it has become invasive and is considered a weed. Kahili Ginger has large, showy flowers that are yellow and red in color and emit a strong fragrance.

Type

Perennial

Family

Zingiberaceae

Control

To manage Kahili Ginger, it is important to remove it before it goes to seed. This can be done by hand-pulling or using a hoe to cut the stem below the soil surface. Mulching can also help to suppress growth and prevent seed germination. If chemical control is necessary, herbicides containing glyphosate or triclopyr can be effective. 

However, it is important to follow label instructions carefully and use caution to avoid damage to non-target plants. In some cases, repeated applications may be necessary to fully control Kahili Ginger. Additionally, preventing the spread of the plant by not planting it and properly disposing of any plant material can help to prevent its establishment in new areas.

Kahili Ginger (Hedychium gardnerianum)

Kikuyu Grass (Pennisetum clandestinum)

Kikuyu Grass, also known as Pennisetum clandestinum, is a perennial weed that belongs to the Poaceae family. It is native to Africa but has been introduced to other parts of the world, including Hawaii, where it has become invasive and is considered a weed. Kikuyu Grass has a creeping growth habit and can form dense mats that can outcompete other plants.

Type

Perennial

Family

Poaceae

Control

To control Kikuyu Grass, it is important to remove it before it goes to seed. This can be done by hand-pulling or using a hoe to cut the stem below the soil surface. Mulching can also help to suppress growth and prevent seed germination. 

If chemical control is necessary, herbicides containing glyphosate or fluazifop-p-butyl can be effective. Repeated applications may be necessary to fully control Kikuyu Grass. Additionally, maintaining a healthy lawn through proper watering, fertilization, and mowing can help to prevent the growth of Kikuyu Grass.

Guinea Grass (Megathyrsus maximus)

Guinea Grass, also known as Megathyrsus maximus, is a perennial weed that belongs to the Poaceae family. It is native to Africa but has been introduced to other parts of the world, including Hawaii, where it has become invasive and is considered a weed. Guinea Grass has a tall, upright growth habit and can form dense stands that can outcompete other plants.

Type

Perennial

Family

Poaceae

Control

To control Guinea Grass, it is important to remove it before it goes to seed. This can be done by hand-pulling or using a hoe to cut the stem below the soil surface. Mulching can also help to suppress growth and prevent seed germination. If chemical control is necessary, herbicides containing glyphosate or imazapyr can be effective. 

However, it is important to follow label instructions carefully and use caution to avoid damage to non-target plants. In some cases, repeated applications may be necessary to fully control Guinea Grass. Additionally, maintaining a healthy lawn through proper watering, fertilization, and mowing can help to prevent the growth of Guinea Grass.

Hilo Grass (Paspalum conjugatum)

Hilo Grass, also known as Paspalum conjugatum, is a perennial weed that belongs to the Poaceae family. It is native to tropical regions of the Americas but has been introduced to other parts of the world, including Hawaii, where it has become invasive and is considered a weed. Hilo Grass has a creeping growth habit and can form dense mats that can outcompete other plants.

Type

Perennial

Family

Poaceae

Control

It is important to remove it before it goes to seed. This can be done by hand-pulling or using a hoe to cut the stem below the soil surface. Mulching can also help to suppress growth and prevent seed germination. If chemical control is necessary, herbicides containing glyphosate or sethoxydim can be effective. However, it is important to follow label instructions carefully and use caution to avoid damage to non-target plants.

Fountain Grass (Pennisetum setaceum)

Fountain Grass, also known as Pennisetum setaceum, is a perennial weed that belongs to the Poaceae family. It is native to Africa but has been introduced to other parts of the world, including Hawaii, where it has become invasive and is considered a weed. Fountain Grass has a clumping growth habit and can grow up to six feet tall. It produces feathery, pink or purple flowers that can spread its seeds over a wide area.

Type

Perennial

Family

Poaceae

Control

Mulching can help to suppress growth and prevent seed germination. If chemical control is necessary, herbicides containing glyphosate or imazapyr can be effective. However, it is important to follow label instructions carefully and use caution to avoid damage to non-target plants. 

In some cases, repeated applications may be necessary to fully control Fountain Grass. Additionally, preventing the spread of the plant by not planting it and properly disposing of any plant material can help to prevent its establishment in new areas.

Fountain Grass (Pennisetum setaceum)

Mexican Clover (Richardia brasiliensis)

Mexican Clover, also known as Richardia brasiliensis, is an annual weed that belongs to the Rubiaceae family. It is native to South America but has been introduced to other parts of the world, including Hawaii, where it has become invasive and is considered a weed. Mexican Clover has a low-growing, spreading habit and can form dense mats that can outcompete other plants.

Type

Aannual

Family

Rubiaceae

Control

To manage Mexican Clover, it is important to remove it before it goes to seed. This can be done by hand-pulling or using a hoe to cut the stem below the soil surface. Mulching can also help to suppress growth and prevent seed germination. If chemical control is necessary, herbicides containing glyphosate or triclopyr can be effective. 

However, it is important to follow label instructions carefully and use caution to avoid damage to non-target plants. In some cases, repeated applications may be necessary to fully control Mexican Clover.

Mexican Clover

Lovegrass (Eragrostis variabilis)

Lovegrass, also known as Eragrostis variabilis, is an annual weed that belongs to the Poaceae family. It is native to North America but has been introduced to other parts of the world, including Hawaii, where it has become invasive and is considered a weed. Lovegrass has a tufted growth habit and can grow up to three feet tall. It produces a large number of seeds that can spread over a wide area.

Type

Annual

Family

Poaceae

Control

To manage Lovegrass, it is important to remove it before it goes to seed. This can be done by hand-pulling or using a hoe to cut the stem below the soil surface. Mulching can also help to suppress growth and prevent seed germination. 

If chemical control is necessary, herbicides containing glyphosate or sethoxydim can be effective. However, it is important to follow label instructions carefully and use caution to avoid damage to non-target plants. Additionally, maintaining a healthy lawn through proper watering, fertilization, and mowing can help to prevent the growth of Lovegrass.

Blackberry Nightshade (Solanum nigrum)

Blackberry Nightshade, also known as Solanum nigrum, is an annual weed that belongs to the Solanaceae family. It is native to Europe but has been introduced to other parts of the world, including Hawaii, where it has become invasive and is considered a weed. Blackberry Nightshade has a branching growth habit and can grow up to three feet tall. It produces small, black berries that are poisonous to humans and animals.

Type

Annual

Family

Solanaceae

Control

To manage Blackberry Nightshade, it is important to remove it before it goes to seed. This can be done by hand-pulling or using a hoe to cut the stem below the soil surface. Mulching can also help to suppress growth and prevent seed germination. If chemical control is necessary, herbicides containing glyphosate or 2,4-D can be effective. 

However, it is important to follow label instructions carefully and use caution to avoid damage to non-target plants. In some cases, repeated applications may be necessary to fully control Blackberry Nightshade. Additionally, preventing the spread of the plant by not planting it and properly disposing of any plant material can help to prevent its establishment in new areas.

Blackberry Nightshade (Solanum nigrum)

Fireweed (Senecio madagascariensis)

Fireweed, or Senecio madagascariensis, is a perennial weed species that is native to Madagascar but has become invasive in many parts of the world. It can grow up to 3 feet tall and produces small yellow flowers and lobed leaves. Fireweed belongs to the Asteraceae family, which includes many important food crops. However, it is considered a weed due to its invasive nature and ability to outcompete other plants.

Type

Perennial

Family

Asteraceae

Control

Controlling Fireweed can be challenging due to its ability to produce large amounts of seeds that can quickly spread. To prevent the growth and spread of Fireweed, it is important to maintain a healthy lawn or garden and use appropriate herbicides when necessary. 

Regular mowing and hand-pulling can also be effective for small infestations. By taking proactive measures and using appropriate control methods, it is possible to effectively manage and prevent the growth of Fireweed in a lawn or garden.

Fireweed

Australian Tree Fern (Cyathea cooperi)

The Australian Tree Fern, or Cyathea cooperi, is a perennial fern species native to Australia. It is a popular ornamental plant due to its attractive fronds and ability to grow in a variety of conditions. As a perennial plant, it can live for many years and is often used in landscaping to add a tropical or exotic feel to gardens.

The Australian Tree Fern belongs to the Cyatheaceae family, which includes many other fern species. Overall, the Australian Tree Fern is a beautiful and versatile ornamental plant that can thrive in many different conditions, but care must be taken to prevent its spread in natural ecosystems. In gardens and landscaping, it can be a low-maintenance and attractive addition to any outdoor space, providing a lush and tropical feel.

Type

Perennial

Family

Cyatheaceae

Control

While it is not typically considered an invasive species, it can spread rapidly in some conditions and may require control methods such as hand-pulling or herbicide application to prevent it from outcompeting other plants.

Australian Tree Fern

Japanese Knotweed (Fallopia japonica)

Japanese Knotweed, or Fallopia japonica, is a perennial weed species that is native to Japan and has become invasive in many parts of the world, including North America and Europe. 

It can grow up to 10 feet tall and is characterized by its bamboo-like stems and small, white flowers. Japanese Knotweed is considered a serious threat to natural ecosystems due to its ability to outcompete native plant species and cause damage to infrastructure, such as buildings and roads.

Japanese Knotweed belongs to the Polygonaceae family, which includes many other weed species such as bindweed and buckwheat. Controlling Japanese Knotweed can be challenging due to its deep root system and ability to regrow from small fragments of the plant.

Type

Perennial

Family

Polygonaceae

Control

Effective control methods include herbicides such as glyphosate or picloram, as well as physical removal of the plant and its root system. Care must be taken to properly dispose of any plant material to prevent further spread of the species. Overall, Japanese Knotweed is a challenging perennial weed species to control, but it is important to take proactive measures to prevent its spread and protect natural ecosystems.

Japanese Knotweed washington

Lantana (Lantana camara)

Lantana, or Lantana camara, is a perennial shrub species that is native to the tropical regions of South America but has become invasive in many parts of the world, including North America, Africa, and Asia. It can grow up to 6 feet tall and is characterized by its colorful flowers and strong scent. 

Lantana is considered a serious threat to natural ecosystems due to its ability to outcompete native plant species and alter soil composition.

Lantana belongs to the Verbenaceae family, which includes many other ornamental plant species such as verbena and butterfly bush.

Type

Perennial

Family

Verbenaceae

Control

Controlling Lantana can be challenging due to its ability to produce large amounts of seeds and quickly spread to new areas. Effective control methods include herbicides such as glyphosate or triclopyr, as well as physical removal of the plant and its root system. Care must be taken to properly dispose of any plant material to prevent further spread of the species.

Lantana (Lantana camara)

Brazilian Pepper (Schinus terebinthifolius)

Brazilian Pepper, or Schinus terebinthifolius, is a perennial tree species that is native to South America but has become invasive in many parts of the world, including North America and Australia. It can grow up to 30 feet tall and is characterized by its red berries and pinnate leaves. 

Brazilian Pepper is considered a serious threat to natural ecosystems due to its ability to outcompete native plant species and alter soil composition.

Brazilian Pepper belongs to the Anacardiaceae family, which includes many other important tree species such as cashews and mangoes.

Type

Perennial

Family

Anacardiaceae

Control

Controlling Brazilian Pepper can be challenging due to its ability to produce large amounts of seeds and quickly spread to new areas. Effective control methods include herbicides such as glyphosate or triclopyr, as well as physical removal of the tree and its root system. 

Care must be taken to properly dispose of any plant material to prevent further spread of the species. Biological control methods, such as the introduction of natural predators or disease, may also be effective in managing Brazilian Pepper populations.

Brazilian Pepper (Schinus terebinthifolius)

Christmas Berry (Schinus molle)

Christmas Berry, or Schinus molle, is a perennial tree species that is native to South America but has become invasive in many parts of the world, including North America and Australia. It can grow up to 50 feet tall and is characterized by its small, red berries and pinnate leaves. 

Christmas Berry is considered a serious threat to natural ecosystems due to its ability to outcompete native plant species and alter soil composition. Christmas Berry belongs to the Anacardiaceae family, which includes many other important tree species such as cashews and mangoes.

Type

Perennial

Family

Anacardiaceae

Control

Controlling Christmas Berry can be challenging due to its ability to produce large amounts of seeds and quickly spread to new areas. Effective control methods include herbicides such as glyphosate or triclopyr, as well as physical removal of the tree and its root system. 

Care must be taken to properly dispose of any plant material to prevent further spread of the species. Biological control methods, such as the introduction of natural predators or disease, may also be effective in managing Christmas Berry populations.

Christmas Berry (Schinus molle)

Elephant Grass (Pennisetum purpureum)

Elephant Grass, or Pennisetum purpureum, is a perennial grass species that is native to Africa but has been introduced to many parts of the world, including North and South America, Asia, and Australia. It can grow up to 10 feet tall and is characterized by its large, coarse leaves and tall, thick stems. Elephant Grass is commonly used for livestock feed, biofuel production, and erosion control.

Elephant Grass belongs to the Poaceae family, which includes many other important grass species such as corn and wheat.

Type

Perennial

Family

Poaceae

Control

Controlling Elephant Grass can be challenging due to its ability to grow quickly and form dense stands that can outcompete other plant species. Effective control methods include herbicides such as glyphosate or imazapyr, as well as physical removal of the grass and its root system. 

Care must be taken to properly dispose of any plant material to prevent further spread of the species. Grazing by livestock or mowing can also be effective in controlling the growth of Elephant Grass.

Christmas Berry (Schinus molle)

Broadleaf Dock (Rumex obtusifolius)

Broadleaf Dock, or Rumex obtusifolius, is a perennial weed species that is native to Europe but has become invasive in many parts of the world, including North America and Australia. 

It is characterized by its broad, oval-shaped leaves and tall, slender stems. Broadleaf Dock is a challenging perennial weed species to control due to its deep root system and ability to regrow from small fragments of the plant.

Broadleaf Dock belongs to the Polygonaceae family, which includes many other weed species such as knotweed and buckwheat.

Type

Perennial

Family

Polygonaceae

Control

Effective control methods include herbicides such as glyphosate or 2,4-D, as well as physical removal of the plant and its root system. Care must be taken to properly dispose of any plant material to prevent further spread of the species. Regular mowing or grazing by livestock can also be effective in controlling the growth of Broadleaf Dock. Overall, it is important to take proactive measures to prevent the spread of Broadleaf Dock and protect natural ecosystems.

Elephant Grass (Pennisetum purpureum)

Bindweed (Convolvulus arvensis)

Bindweed, or Convolvulus arvensis, is a perennial weed species that is native to Europe but has become invasive in many parts of the world, including North America and Australia. 

It is characterized by its twining stems and funnel-shaped flowers, which can be white or pink. Bindweed is considered a serious threat to natural ecosystems due to its ability to outcompete native plant species and reduce crop yields.

Bindweed belongs to the Convolvulaceae family, which includes many other weed species such as morning glory and sweet potato.

Type

Perennial

Family

Convolvulaceae

Control

Controlling Bindweed can be challenging due to its deep root system and ability to regrow from small fragments of the plant. Effective control methods include herbicides such as glyphosate or 2,4-D, as well as physical removal of the plant and its root system. 

Care must be taken to properly dispose of any plant material to prevent further spread of the species. Regular mowing or grazing by livestock can also be effective in controlling the growth of Bindweed. Overall, it is important to take proactive measures to prevent the spread of Bindweed and protect natural ecosystems.

garden beds Bindweed

Purslane (Portulaca oleracea)

Purslane, or Portulaca oleracea, is an annual weed species that is native to Europe but has become naturalized in many parts of the world, including North America and Asia. It is characterized by its succulent leaves and small, yellow flowers. Purslane is considered a nuisance weed in many agricultural settings, as it can reduce crop yields and compete with other plants for resources.

Purslane belongs to the Portulacaceae family, which includes many other succulent plant species such as moss rose and rock purslane. Overall, it is important to take proactive measures to prevent the spread of Purslane and protect agricultural crops.

Type

Annual

Family

Portulacaceae

Control

Controlling Purslane can be challenging due to its ability to produce large amounts of seeds and quickly spread to new areas. Effective control methods include herbicides such as glyphosate or 2,4-D, as well as physical removal of the plant and its root system. Care must be taken to properly dispose of any plant material to prevent further spread of the species. Regular mowing or cultivation can also be effective in controlling the growth of Purslane.

Purslane

Wild Radish (Raphanus raphanistrum)

Wild Radish, or Raphanus raphanistrum, is an annual or biennial weed species that is native to Europe but has become invasive in many parts of the world, including North America and Australia. 

It is characterized by its small, white or purple flowers and long, slender seed pods. Wild Radish is considered a serious threat to natural ecosystems and agricultural crops due to its ability to outcompete native plant species and reduce crop yields.

Wild Radish belongs to the Brassicaceae family, which includes many other important plant species such as broccoli and mustard. Overall, it is important to take proactive measures to prevent the spread of Wild Radish and protect natural ecosystems and agricultural crops.

Type

Annual or biennial

Family

Brassicaceae

Control

Controlling Wild Radish can be challenging due to its ability to produce large amounts of seeds and quickly spread to new areas. Effective control methods include herbicides such as glyphosate or 2,4-D, as well as physical removal of the plant and its root system. 

Care must be taken to properly dispose of any plant material to prevent further spread of the species. Regular mowing or cultivation can also be effective in controlling the growth of Wild Radish.

Wild Radish

Yellow Woodsorrel (Oxalis stricta)

Yellow Woodsorrel, or Oxalis stricta, is a perennial weed species that is native to North America but has become invasive in many parts of the world, including Europe and Asia. 

It is characterized by its clover-like leaves and small, yellow flowers. Yellow Woodsorrel is considered a nuisance weed in many agricultural settings, as it can reduce crop yields and compete with other plants for resources.

Yellow Woodsorrel belongs to the Oxalidaceae family, which includes many other important plant species such as sorrel and shamrock. Overall, it is important to take proactive measures to prevent the spread of Yellow Woodsorrel and protect agricultural crops.

Type

Perennial

Family

Oxalidaceae

Control

Controlling Yellow Woodsorrel can be challenging due to its ability to produce large amounts of seeds and quickly spread to new areas. Effective control methods include herbicides such as glyphosate or 2,4-D, as well as physical removal of the plant and its root system. 

Care must be taken to properly dispose of any plant material to prevent further spread of the species. Regular mowing or cultivation can also be effective in controlling the growth of Yellow Woodsorrel.

Yellow woodsorrel
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Oliver Wright
Oliver Wright

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