Speedwell

Wireweed (Polygonum aviculare) is a widespread annual with wiry, trailing stems that form mats up to 1 m in width. Wireweed (or wire weed) prefers to germinate in wet soils so it is problematic in winter and in spring sown crops as it can be very competitive and smother crops. Once larger than a seedling, is difficult to control, with selective herbicides in crops.

Fumitory (Fumaria muralis) is a weak-stemmed scrambling and climbing annual weed with purple/pink tubular flowers. It is common throughout New Zealand and is a significant weed of crops (especially cereals) as it can smother crops if not controlled.

A member of the Brassicaceae family, wild turnip (Brassica rapa subsp. sylvestris) is a persistent annual found in arable crops in Canterbury and Southland, and throughout New Zealand. Sometimes known as field mustard, the lower leaves have bristly hairs and are divided into pairs of lobes on the lower half of the leaf, whilst the upper part is one large terminal lobe. The upper leaves are smooth and lance-shaped. The flowers are bright yellow with four petals. The open flowers are at the top of the branched stems; the unopened buds below. The flowers later form linear pods.