The Weed Science Program’s goal at MSU is to provide science-based research and extension information on integrated weed management in field crops. Weed control, management, ecology, and minutia "He put another parable before them, saying, 'The kingdom of heaven is like a grain of mustard seed that a man took and sowed in his field. It is the smallest of all seeds, but when it has grown it is larger than all the garden plants and becomes a tree, so that the birds of the air come and make nests in its branches.'” Matthew 13:31-32 This wonderful story is the basis for
Winter/summer annual. Emerges in late summer, early fall or spring. In Michigan, several populations of wild mustard act as a summer annual. Flowering peaks in June and July, but can continue until the first frost.
Emerges from soil depths of 1-inch or less.
Production Range: Approximately 1,200 seeds per plant.
Dispersal Mechanisms: Seed pod dehiscence (splitting open).
Longevity: Low persistence – 50% of the seed bank is reduced in less than one year, and it takes seven years to reduce the seed bank 99%.
Dormancy: Initially dormant. Dormancy is broken by a combination of changes in temperature, light, and nitrate levels.
One of the more competitive weeds with small grains, soybean, and corn. Winter cereal yields were reduced 13 to 69%, when the biomass was comprised of 1 to 60% wild mustard. Soybean yields were reduced 46% with 4 plants per yard of row and corn yields were reduced 1.5- to 2-fold and 5- to 6-fold at low and high wild mustard densities, respectively.
Preferred Soil/Field Conditions:
Grows on a wide range of soils.
Predation/grazing: Ground beetles (carabids) eat wild mustard seed lying on the soil surface.
Decay: No information.
Tillage: Seedlings are readily killed by tillage.
Rotary Hoeing: Hoe before weeds exceed 1/4-inch in height, once established wild mustard is difficult to control.
Flaming: Effective on small wild mustard.
Crop rotation: Corn-soybean rotations will deplete wild mustard populations more rapidly than continuous wheat.
Planting date: Later planting will reduce wild mustard populations.
Application timing and effectiveness: Several herbicides are effective for controlling wild mustard. Control is greater when herbicides are applied to smaller wild mustard plants. Please refer to E-434, “MSU Weed Control Guide for Field Crops,” for herbicide recommendations.
Wild mustard can serve as an alternate host of nematodes and many insect pests.
Mustard Seed Weed
As we start the winter season today, many locals and tourist to our area look forward to the end of winter when the Napa Valley comes alive with the beauty of yellow mustard flower that has been celebrated for many years in the ‘Napa Valley Mustard Festival.’ No one can argue the aesthetic beauty of a hillside vineyard covered in the yellow flower of mustard. Working as the Farm Advisor who oversees vineyard floor management in the Napa Valley, I am at times troubled by the sight. Is there an invasive weed that has ‘taken over’ the vineyards? If it is a covercrop, is it good cover crop? And the question I get most often from grower and city folk alike, ‘What kind of mustard is that?’ Consulting the ‘Weeds of California and Other Western States’ it appears that the Napa Valley has at least five “mustards”; Short-pod mustard (Hirschfeldia incana L.) that can become a short-lived perennial, and four species that are all at some point referred to as ‘Wild Mustard’: Wild mustard (Sinapis arvensis L.); Rapeseed mustard (Brassica napus L.) Black mustard (Brassica nigra L. Koch); and Birdsrape mustard (Brassica rapa L.). How do you tell the difference? To really tell the difference you need to look closely at the flowers and the orientation of the mature fruit in relation to the stem.
Are these mustards weeds or covercrop? The answer, as with most weeds, depends on your perspective. Mustard as a group may be one of the best examples of both. In many parts of the country mustards are a serious weed problem in vegetable and cereal production. However, they also have several properties that make them a good covercrop: large tap root that can break up hard soils, usually germinate and grow quickly, providing erosion control and weed suppression, large biomass that can contribute to the organic matter of the soil, and contain chemical constituents that can provide limited nematode and weed suppression. These ‘mustards’ usually germinate in the fall when the rains start, then flower, and set seed in late winter, in time to mow for frost protection.
So, if wild mustards can act as a covercrop, why, according to many long-time Napa Valley locals, do we have much less mustard than before? There are some properties that make mustard a less than ideal covercrop. Deeply buried seeds of some species can survive for up to 50 years. Early flowering reduces growth and weed competition. Wild mustards break down very quickly and add little organic matter and almost no nitrogen to the soil. A wide variety of more suitable plants are available as covercrops, such as domesticated mustards(White mustard or Daikon radish) that have shown promise of more positive properties without as many of the negative. Other covercrops are better suited to the specific needs of the vineyard. Cereal grains, such as oats or barley are often used where vines are too vigorous or in vineyards that tend to hold moisture in the spring. Many growers utilize a ‘no-till’ system comprised of low-growing annual or perennial grasses, and where organic matter and nitrogen are needed a cereal/legume mix of barley or oats with winter pea or fava (bell) bean is very popular.
The amount of mustard in the valley may have diminished, but there will continue to be an abundance of this attractive yellow flower to enjoy for years to come…
The Mustard Weed
“He put another parable before them, saying, ‘The kingdom of heaven is like a grain of mustard seed that a man took and sowed in his field. It is the smallest of all seeds, but when it has grown it is larger than all the garden plants and becomes a tree, so that the birds of the air come and make nests in its branches.’” Matthew 13:31-32
This wonderful story is the basis for The Mustard Seed the organization in which I work alongside fellow exiles living in poverty and homelessness. In these few words, well-meaning individuals imagine how their small acts of charity can grow tremendously in God’s Kingdom. I myself use this idea often when speaking to enthusiastic children who come and make sandwiches for our community. I have always wondered if there is more to this parable and, consequently, more to the ideas we may have of the Kingdom of Heaven.
When Israelites heard Jesus use the term ‘the Kingdom of Heaven,’ they thought they knew what he was talking about. They were under occupation of the ruthless Roman empire and they were told stories about the coming Kingdom of Heaven – the time when the God of Israel would finally reign as King over his people and the land. If the Jews were to compare the Kingdom of Heaven to any plant they would have probably chosen the cedar (see Ezekiel 17:22-24). Cedars typically grow over 40m high, strong and majestic.
Cedars typically grow over 40m high, strong and majestic.
Jesus was probably playing on the people’s idea of a cedar when he says the mustard seed “becomes a tree”. A mustard tree is more like a bush which can grow up to 3-6 meters. Jesus is saying the Kingdom of Heaven is more like a mustard bush than a tall cedar of Lebanon. Now this would have shocked his audience, especially farmers and gardeners. The mustard tree was potentially a noxious weed, which could take over your garden and crops. At the time, there were even laws prohibiting planting mustard trees by certain crops because of its threat to other plants.
It would be like Jesus coming today and saying, ‘The Kingdom of Heaven is like a dandelion! Even though it is a small seed, it spreads an unstoppable plague across cities.’ Or the Kingdom of Heaven is like a pothole, or a gopher, a pimple, used needles in your lawn. The Kingdom of Heaven is here, but it is more like a weed and pest than a towering tree. To make things even more complicated. Jesus adds that birds will come and perch in its branches. Gardeners and farmers also did not want these pests indulging in their garden. Not only is the Kingdom of Heaven like a weed, it attracts unwanted birds which will further destroy your fields and economic livelihoods!
The Kingdom of Heaven is like a dandelion!
What I believe Jesus is saying is Christians are to be more like weeds in society than uniform trees. The origin of The Mustard Seed, demonstrates this. As in most inner-cities in North American, racial and economic ghettoization forced marginalized groups into city centers while middle class and majority light skinned residents left the inner-city for the suburbs.
The Mustard Seed’s building in Edmonton, AB was completed in 1912 as a German Baptist Church. During the late 70s and early 80s, churches were impacted by the appearance of odd characters nesting in their neighbourhood and church members were seduced by suburbanization. For most of the church – instead of being weeds to the threshing floor of economic injustice; instead of being pests to the policies of segregation – congregants fled the new threats and joined the mainstream trends hoping to find God’s kingdom there. The German church, too, fled to the safety offered by the empire. Thankfully God was not done with them yet. He planted weeds of his own ten years later in the form of a rebellious youth group.
He planted weeds of his own ten years later.
Instead of accepting status quo, these kids challenged the notion that some people lacked the image of God in their design. Instead of being hypnotized by the allure of white fences and trimmed lawns, they actually saw the Kingdom of Heaven for what is really was. And after a providential field trip back to the old church building their elders had abandoned, the youth sacrificed their comfort by secretly bringing individuals experiencing homelessness into a makeshift shelter located in the basement of their new, safe, suburban, church building. In essence, they became thorns of Canadian thistle, inviting all the birds to join. And it worked. With some resistance, the church slowly began to see once again the Kingdom of Heaven in all of their neighbours and purchased their former church back to be haven for those needing a home. The Kingdom of Heaven is like that. It means being a weed to society and church culture so that they may see the Kingdom of Heaven for what it truly is.