cut-leaved geranium, jagged-leaved crane
Geranium dissectum L.
Cut-leaved crane's-bill is a native annual that can act as a biennial or winter annual. It is common throughout the UK on grassy and stony ground, waste places, hedge banks and cultivated land. It is found on heavy land, but is also common on light sandy, calcareous and loamy soils. It is recorded up to 1,250 ft in Britain.
Cut-leaved crane's-bill has often been associated with temporary grass leys or clover seed crops, having been introduced with the crop seed. In a survey of weeds in conventional winter oilseed rape in central southern England in 1985 it was found in 13% of the fields surveyed but was largely confined to the field margins, probably as a result of herbicide application within the cropped area. A study of the weed flora of southern England between 1960 and 1997 suggested that cut-leaved crane's-bill was increasing in frequency.
Cut-leaved crane's-bill flowers from May to August and sometimes into October. The seed number per plant is given as 50 to 200 but a large plant may produce 10,000 to 20,000 seeds.
Seed sown in the field and cultivated periodically emerged from April to September. Very few seedlings emerged during the rest of the year. Most seedlings emerged in the first 2 years after sowing. Germination is increased following seed scarification.
Cut-leaved crane's-bill seed buried in mineral soil at different depths and left undisturbed, retained 1 to15% viability after 1 year but no viable seeds remained after 4 years. Seed buried in a peat soil retained only trace viability after just 1 year. Dry-stored seed gave more than 90% germination after 5 years. Seed stored under granary conditions for 1, 4 and 20 years retained 99, 60 and 46% viability respectively.
Cut-leaved crane's-bill seed was a common impurity in home grown clover seed. The seed was a contaminant in red clover, crimson clover and trefoil seed. In clover and grass seed samples tested in Denmark between 1927 and 1969, cut-leaved crane's-bill seed was found in 4 to 18% of samples.
Care should be taken to sow only pure crop seeds. Cut-leaved crane's-bill is easily dealt with in crops that are hoed regularly. In leys the weed may be hand picked to prevent seeding.