Storksbill (Erodium cicutarium)
As a member of the geranium family the winter weed we know as storksbill was originally labelled by that great name dropper Linnaeus in 1753 as Geranium cicutarium. However, by 1785 it had a new look, having been renamed after the Greek word for heron (erodios), given the spikiness of its fruiting body. Somewhere along the line the bird has changed, but I guess storks and herons share long beaks and long legs.
An annual plant, initially it grows at ground level as a filgreed rosette of up to 30cm across. It produces tiny mauve-pink flowers on long red hairy stalks from September to May, at which time it can grow up to 50cm tall. In the US it is known as Redstem Filaree, descriptive of its finely divided leaves and opposite leaflets arranged along the red stems. It is found most commonly in drier areas throughout New Zealand, in arable land, poor pasture, dry tussock and grassland.
It is the fruiting bodies which are the significant and unwelcome parts of the plant. Each seed capsule of up to 4cm long terminates in an upright beak, which is sharp enough to pierce an animal’s skin and work its way into the flesh. Each stem carries up to five of these spikes. As the seeds ripen the awn (seed cover) splits into five corkscrew strips which turn downwards and screw themselves into loose soil to bury the attached seeds. In this way a single plant can become a sizeable patch quite rapidly.
A related species, Erodium moschatum, grows in more fertile soil and is also found in most places throughout New Zealand. This type can be an annual or biennial plant. The plants can be described as sticky-hairy with thicker and greener stems and less dissected leaves. The flowers may be pink or white and have shorter stalks and, if crushed, the leaves have a musky odour.
In spring it can become a major pasture component, particularly where there is bare ground caused by over-grazing or winter stock damage. While some farmers in drier areas claim that it offers good fodder for lambs, it has also been reported as causing photosensitisation and staggers in lambs and cattle.
Like many weeds it is quick to spread, can form a thick mat in pasture, and is difficult to get rid of. In pasture renovation the pre harvest spray out may have it appear to be drying off, but it will regrow and still be present in new pasture. It also can be a problem in lucerne and other crops. It is not very susceptible to 2,4-D but apparently a picloram/triclopyr mixture such as Tordon gives good control. Seek advice from your weedkiller supplier on what is currently considered effective.
It has a short taproot and can be pulled out while still at the rosette stage, although it also develops a fibrous rooting system as the plant grows which makes manual removal more difficult.