Weeds

Scrambling Fumitory is a climbing weed which generally germinates in spring and autumn.  

This annual is a common sight in NZ crops and gardens. It has a celery like leaf, and distinctive pink flowers with purple tips. The stems are quite floppy.

Californian thistle is probably the most invasive broadleaf weed in New Zealand pasture with reports estimating $700 million in lost pastoral farm revenue each year. This perennial thistle limits farm productivity by reducing both pasture production and pasture utilisation. Trials show that 30% ground cover with Californian thistle (13 stems/m2) can cut ewe liveweight gains by 29% over a 12-month period. Californian thistle also triggers scabby mouth disease.

Scrambling Speedwell is a sprawling annual, germinating in both autumn and spring.  Its small blueish white flower is a common sight in gardens and crops, growing more quickly on bare ground.

Fast-growing and persistent, wild turnip is an annual brassica which is common in pastures on a wide range of soils. Flowering stalks can reach 1m high causing loss of pasture yield through competition for resources. Once the plant matures its root reserves make it harder to control. 

Wireweed is a summer annual which establishes very early in Spring, expecially in wetter soil. It establishes well in bare soil, and is very tollerant of tredding, making it a common sight around farm gates and paths

Storksbill is a low-growing, tap-rooted annual that thrives in low fertility pastures. It can cause problems in both new and established pastures, particularly in spring. Seedheads damage animal pelts. Storksbill has also been recorded as causing staggers and photo-sensitisation in lambs and cattle.

Because it is able to germinate and grow right through the year, Shepherd's purse's distinctive 10-15cm wide rosette shape is often noticed in winter when there is least competition. 

Its long lasting seeds has been seen to last decades in the soil. It can go through multiple generations in a single year.

Spurrey is in annual weed, also known as Yarr, usually getting established in autumn and flowering in spring. The flowers are small and white and clustered at the ends of the stem. Its seeds can remain dormant in soil for several years, re emerging when plowing brings up burried seeds.

Yellow Bristle Grass has now spread along roadsides throughout most of the North Island and has become a major problem on farms.

As a summer growing annual, yellow bristle grass reproduces only by seed. Seeds are dispersed by water, soil movement, animals, machinery, and as contaminants of crop seed and hay.

Pennyroyal is now prevalent in many areas and different soil types and is becoming predominant in run out pastures. Invasive and highly unpalatable to stock, pennyroyal forms dense mats of vegetation in pastures, causing inefficient feed utilisation, and taints the milk of lactating dairy cows if they do eat it. 

Prolific and fast growing, it prefers light soils and can withstand dry conditions. Fleabane produces a large number of seeds which can germinate in both spring and autumn. Spray at seedling to small rosette stage.

Hedge Mustard A tap-rooted annual, hedge mustard  can be a problem in newly-sown or open pastures. Seedlings form rosettes which in turn quickly produce upright flowering stems 1m or more high.

Stock avoid this plant, leading to poor pasture utilisation. Control is best achieved at seedling to rosette stage.