Abundant throughout New Zealand, chickweed (Stellaria media) is a challenging annual weed in new pasture and crops. With its quick, low growing and sprawling habit (up to 40 cm), chickweed will easily choke developing crops. Chickweed favours good moisture conditions so is problematic in winter and spring.
- Light green
- Apex pointed
- Base rounded, stalked
- Opposite in pairs
- Ovate with pointed tip
As it matures, chickweed with its low growing habit will spread out to 40 cm. The round stems are thin, branched and weak being easily broken. The leaves are soft, green and up to 2 cm long. The leaves are in opposite pairs on hairy stalks.
White star-like flowers are produced on slender stalks. The flowers are 1 cm in diameter with 5 deeply divided petals. Chickweed grows very rapidly and can produce seeds within 6 weeks of germination. A plant can produce 10-20,000 seeds.
Depending upon the crop controlling 5-10 wild oats per square meter will result in an economic response. Wild oats also produce a large number of long-lived seeds, often as many as 150 per panicle with many panicles per plant. Wild oat seeds can remain viable in the soil for several years and the common saying “one year’s seeding, 7 years weeding” stands very true for wild oats. Wild oats can be successfully controlled with selective herbicides such as Puma S. However, if numbers are low hand rogueing should be undertaken if possible.
Plantago lanceolata, Plantago major
Scentless Chamomile (Matricaria perforata) is a bushy annual or biennial plant that grows to 60 cm and is wholly or almost scentless. It has an erect stem, with branches only from mid stem upwards. The leaves are fern like and sticky. The flowers are large, with twelve white petals, with central yellow disc florets, giving the flower a daisy-like appearance. They appear singly on stems and branches between December and March.
Found in moist disturbed areas such as roadsides, cropland, pasture, drainage ditches and waste areas. The seeds are 2 mm, dark brown with a raise edge, and each plant produces 10,000 - 200,000 seeds which germinate in shallow soil.
Storksbill (Erodium cicutarium) is an invasive, sticky, hairy plant which grows in rossetes up to 30 cm across. It is widespread throughout New Zealand in drier coastal and lowland areas, and found in pasture, grassland and arable land. The leaves are pinnate, resemble ferns, and are divided into pairs of leaflets. The flowers are a mauve-pink colour, have five undivided petals, and are arranged in loose clusters on reddish coloured hairy stalks. Flowering is September to May.
The seeds are contained in a long seed-pod which resembles the bill of a stork. When ripe the seed-pod bursts open into five strips, launching the seeds like little parachutes, or by means of the strips which have seeds attached to them, burying themselves into loose soil.