Lapsana communis L
Nipplewort is an erect annual, native in open woods, hedgerows, waste places and rough ground. It is common throughout the UK and is recorded up to 1,500 ft. Nipplewort is frequent in cultivated fields, field margins and hedgerows. When nipplewort occurs in the hedge bottom, plants are often found spreading into the arable field. Nipplewort is also a common garden weed. It appears to grow best on loam and clay soils. In a survey of weeds in conventional winter oilseed rape in central southern England in 1985 it was found in 3% of the fields surveyed.
Two subspecies are recognised in the UK. Subspecies communis is the native annual, while ssp. intermedia is an introduced annual to perennial form recorded in just a few places.
Nipplewort has medicinal and therapeutic uses and was sometimes eaten as a salad plant.
Nipplewort flowers from June to September. The flowers are visited by insects but are often self-pollinated. Seed is set from July to October. The average plant has 1,000 seeds but this can be much higher in ruderal habitats. The seeds from the outer florets are longer than those from the inner ones.
In the field, nipplewort seed germinates in autumn and spring. After burial in soil seeds require light for germination. Seed sown in a layer of field soil and cultivated at regular intervals, emerged mainly from March to May with a smaller flush of emergence in August to October. Most seedlings emerged in the year after sowing with just a few emerging over the following 4 years. Seedlings that emerge in the autumn overwinter as a rosette of leaves.
Nipplewort seed exhibits limited soil persistence. Seed sown in the field and followed over a 5-year period in winter wheat or spring barley showed an annual decline rate of around 80%. The emerged seedlings represented 15% of the seedbank. Seedling emergence declined considerably after the 3rd year of the study.
In cereal seed samples tested in 1961-68, nipplewort seed was a contaminant in up to 1.7% of rye, 2.7% of oats, 0.7% of barley and 1.5% of wheat samples tested. In a survey of weed seed contamination in cereal seed in drills ready for sowing in spring 1970, nipplewort was found in 6% of samples. Most of this was home saved seed. In clover and grass seed samples tested in Denmark for the period 1966-1969, nipplewort was one of the most frequent contaminant being found in around 20% of samples.
The weed is kept under control by thorough cultivation and free use of the hoe. Seeding should be prevented and the introduction of nipplewort seed with crop seed avoided. Nipplewort plants in the field margins should be trimmed back to prevent them seeding.
Updated October 2007.