Montana Field Guide

PLANTS: A rhizomatous perennial forb with erect stems that grow 20-80 cm tall. Plants are glabrous (lacks hairs). Plants have basal and erect stems. Source: Lesica et al. 2012

LEAVES: Basal leaves have long petioles (stalks). Basal leaf blades are spoon-shaped to round and shallowly lobed (crenate). Cauline leaves are alternately arranged, petiolate but become sessile upwards. Sources: Lesica et al. 2012; Davis and Mangold 2018.

INFLORESCENCE: Flower heads are mostly solitary on long peduncles (stems). Flower heads are 1-2 cm wide and have white ray florets and yellow disk florets. Involucral bracts are, uneven, in 2-4 rows, and green with brown scarious margins. The flower head’s receptacle is nearly flat and naked (lacks awns, scales or bristles between the disk florets/achenes). The 15-35 ray florets have white petals of 1-2 cm and are fertile. The numerous disk florets have yellow petals, lack a pappus, are 2-3 mm tall, and have flattened style branches. Sources: Lesica et al. 2012; Davis and Mangold 2018.

The genus Leucanthemum comes from the Greek words leuco- for white and anthemon for flower. The specific epithet vulgare means common.

Oxeye Daisy flowers from spring to fall (FNA 2006).

Oxeye Daisy – Leucanthemum vulgare, exotic and noxious:
* Tall plants (20-80 cm) that have the stereotypical “daisy” appearance of white petals with yellow centers.
* Leaves are lobed or toothed less than half-way to their mid-vein.
* Involucral bracts are in 2 to 5 rows and unequal, and with very few hairs (glabrate).

Lawn Daisy - Bellis perennial, exotic and undesirable:
* Short (5-15 cm) plants that have the stereotypical “daisy” appearance of white petals with yellow centers.
* Leaves are entire to toothed.
* Involucral bracts are in a single row, narrowly ovate, and with hairs (strigose).

In Montana Oxeye Daisy grows mostly in moist area along roadsides and in fields, meadows, forest openings, and pastures converted from forest in the valleys to montane zones (Lesica et al. 2012). Elsewhere it is also found along railroad embankments and waste areas.

Oxeye Daisy is a strong competitor that forms dense populations, especially in pastures (Olson and Wallander in Sheley and Petroff 1999). Oxeye Daisy has a small taproot and shallow, branching rhizomes which can replace the often large fibrous root system of grasses (Olson and Wallander in Sheley and Petroff 1999). This can lead to an increase in soil erosion, particularly along waterways. To establish, it is thought that Oxeye Daisy needs some vegetative disturbance. Oxeye Daisy does not germinate well in relatively thick litter layers, but easily germinate on bare soil.

Oxeye daisy has wide tolerance to soil conditions, but grows best in soils ranging from a pH of 6.5-7.0 (Olson and Wallander in Sheley and Petroff 1999). It is more commonly found on alkaline (basic) or neutral soils and less often on acidic soils. It grows well on both nutrient-rich and -poor soils. It has a moderate requirement for nitrogen. A study found that plants grown under low nutrient levels, allocated more biomass to the root system and less biomass to flowering (Olson and Wallander in Sheley and Petroff 1999). It has been observed to be more prolific on poorer soils, which may not indicate a preference, but could indicate that it does not compete as well with established plants on fertile soil (Olson and Wallander in Sheley and Petroff 1999).

Light can affect reproduction, whereas soil nutrient levels did not. A study found that shaded plants allocated more resources to flowering, suggesting it is a strategy to maximize their seed production (Olson and Wallander in Sheley and Petroff 1999).

Oxeye Daisy is usually found in moist areas, but it tolerates droughts (Olson and Wallander in Sheley and Petroff 1999). It is a pioneer species in some habitats exposed to drying soil conditions. Where water stressed, the deeper-rooting Common Dandelion has been found to wilt before Oxeye Daisy. Seedlings are considered drought tolerant.

GRAZING [Adapted from Olson and Wallander in Sheley and Petroff 1999]
Horses, sheep and goats will graze Oxeye Daisy, while cattle and pigs avoid it because it is acrid.
In a study where Oxeye Daisy made up 20% of the plant community, it greatly increased under continuous cattle grazing (Norman 1957). Under rotation grazing by cattle or close rotational and continuous grazing by sheep it increased less.

In a study in southwestern Montana, high cattle densities for short time periods were used to examine if cattle could overcome the tendency to avoid Oxeye Daisy. Two years of intensive grazing reduced seedling and rosette stages, but had no effect on adult Oxeye Daisy plants when compare with adjacent, ungrazed exclosures. It was also observed that cows would pull up mature adult plants, but not eat them probably because of its acridity.

When cows remove the inflorescence, many lateral stems quickly develop. It was found that less than 40% of seeds remain viable if passed through the digestive system of a cow.

CULTURAL
Oxeye Daisy is used as good by humans; Italians use it in salads (Olson and Wallander in Sheley and Petroff 1999).

Plants reproduce by seeds and rhizomes.

ROOTS
Oxeye Daisy has a small taproot, branched rhizomes, and adventitious roots. The prostrate stems easily root. Branched rhizomes grow shallow in the soil profile.

FRUITS
Fruit is an achene. Achenes are cylindric, 1-3 mm long, ribbed, and glabrous (Lesica et al. 2012).
Plants produce an abundance of seeds, from 1,300 to 4,000 seeds per small plant to 26,000 seeds per vigorous plant (Olson and Wallander in Sheley and Petroff 1999).

LIFE CYCLE [Adapted from Olson and Wallander in Sheley and Petroff 1999]
Germination typically occurs in the spring, but can occur throughout the growing season. Germination is not reliant on particular conditions of light, nitrates, chilling, or seed coat scarification (sulphuric acid treatment). Upon germination a pair of cotyledons is produced above the soil surface. They wither when the first true-leaf develops at the soil surface. At about the 6-leaf stage, the primary root starts to be replaced by a system of lateral roots which grow shallowly. The main root loses its importance as the rhizomes develop. Perennating buds at the soil surface on the rhizome are protected by snow or organic debris (hemicryptophyte).

The “juvenile” stage of development is marked by a rosette of basal leaves. An individual plant can bear one to many rosettes on the ground surface. Each rosette typically produces one flowering stem. Thus, through time plants produce a dense mat of rosettes.

Plants flower from spring to fall. Seeds mature 10 days after flowers open (Georgia 1914), thus there is no dormancy period. Seed viability is long-lived. A study found that 82% of buried seeds were viable after 6 years and 1% of them were viable after 39 years.

DISPERSAL
Seeds lack a pappus which reduces the distance that wind can carry them. Hence, seeds often land near to their parents. Seeds can be carried in the fur of livestock and other animals. Seeds can easily contaminate grass seed, which has been a means of dispersal in the U.S.

An integrated vegetative management approach provides the best long-term control of Oxeye Daisy. It requires that land-use objectives and a desired plant community be identified (Shelly et al.in Sheley and Petroff 1999). Once identified the integrated weed management strategy can promote a weed-resistant plant community and serves other land-use objectives such as livestock forage, wildlife habitat, or recreation can be developed, making control of Oxeye Daisy possible.

PREVENTION
Oxeye Daisy is often encouraged as an ornamental to plant, and has been found in numerous seed mixes. Users should carefully read packaging labels and not purchase if its scientific names or common names or any synonyms are listed.

Seed development must be prevented to reduce or stop spread.
* Prevent vehicles from driving through and animals from grazing within infested areas,
* Thoroughly wash the undercarriage of vehicles and wheels in a designated area before moving to an uninfested area,
* Encourage landowners to frequently monitor their land for new infestations and, when found to implement effective control methods.
* Maintain proper livestock grazing management to encourage competitive vegetation, and
* Develop educational campaigns to teach people to not pick and transport the white flowers.


PHYSICAL and CULTURAL CONTROLS [Adapted from Olson and Wallander in Sheley and Petroff 1999]
Hand-pulling can be effective for small or new infestations. It should be done before plants have flowered. Gloves should be worn to protect skin. Plants should be bagged, allowed to desiccate or rot, and then be deposited in the landfill.

mowing as soon as flower buds develop is effective to reduce seed production. However, mowing will stimulate shoot production, and subsequent flowering could occur if conditions are good. Not mowing fields with Oxeye Daisy is also not a good control method because over-time Oxeye Daisy will likely succeed.

Tilling that is repeated in the same growing season can kill plants because rhizomes grow shallow in the soil profile. Seeds in the seedbank will germinate, and require follow-up treatment.

GRAZING CONTROLS [Adapted from Olson and Wallander in Sheley and Petroff 1999]
Horses, sheep and goats will graze Oxeye Daisy, while cattle and pigs avoid it because it is acrid.
Information on how horses, sheep, or goats can be used to control Oxeye Daisy was not found.

Horses, sheep, and goats that graze where Oxeye Daisy grows should be retained in a holding pen before moving into uninfested areas.

Grazing management that maintain vigorous growth of desirable plants will help compete against Oxeye Daisy.

CHEMICAL CONTROLS [Adapted from Olson and Wallander in Sheley and Petroff 1999]
The herbicide type and concentration, application time and method, environmental constraints, land use practices, local regulations, and other factors will determine its effectiveness and impact to non-target species. Strict adherence to application requirements defined on the herbicide label will reduce risks to human and environmental health. Consult your County Extension Agent and/or Weed District for information on herbicidal control. Consult your County Extension Agent and/or Weed District for more information on herbicidal control. Chemical information is also available at Greenbook.

Oxeye daisy is moderately resistant to some 2,4-D-based herbicides except at high rates of 5 pounds per acre.

One study found that applying 80 pounds of nitrogen fertilizer was a more cost-effective treatment after 7 years that using herbicide alone or in combination with fertilizer. The treatment increased grass yields by 500% over this time. Herbicides can kill plants, while fertilizers promote growth of desirable forage.

Picloram (1.5 pint per acre) mixed with 2,4-D (1 quart) per acre was applied to a heavily infested Oxeye Daisy site in 1990. The treatment provided 100% control, but is not recommended to use for a long-term control method. Herbicides often have to be re-applied every 2-3 years because of the seed bank.

The seed bank and long length of seed viability will allow Oxeye Daisy to return for many years. Therefore, control methods that encourage the growth of vigorous, competitive desirable plants is recommended.

BIOLOGICAL CONTROLS [Adapted from Jacobs et al. 2015]
Currently no biological control agents are available.

Useful Links:
Montana Invasive Species website
Montana Biological Weed Control Coordination Project
Montana Department of Agriculture - Noxious Weeds
Montana Weed Control Association
Montana Weed Control Association Contacts Webpage.
Montana Fish, Wildlife, and Parks - Noxious Weeds
Montana State University Integrated Pest Management Extension
Weed Publications at Montana State University Extension - MontGuides

Oxeye Daisy reduces plant species diversity (Olson and Wallander in Sheley and Petroff 1999). It colonizes fields and aggressively out-competes other vegetation to form dense populations. In areas grazed by cattle, Oxeye Daisy is usually avoided because it is acrid. Thus, this allows the plant to flourish and reduces forage availability for cattle.

Grasses often have a large fibrous root system, but can be replaced by Oxeye Daisy that has a small taproot (Olson and Wallander in Sheley and Petroff 1999). This can increase soil erosion, particularly along waterways.