Pasture watch What you need to know about black nightshade

ONE OF the most common weeds

I see in crops and new pasture is black nightshade (Solanum nigrum).

It’s commonly – and wrongly – linked to the rare deadly nightshade (Atropa belladonna), which has only been found in the Christchurch area in small numbers.

Black nightshade is in the same plant family as potatoes, tomatoes, capsicums, tobacco, and aubergines. It’s not commonly eaten in NZ, but if its leaves and ripe berries are cooked the right way, the toxic alkaloids are removed.

This summer annual grows upright to 50cm or so. The large leaves and stems turn from dark green to purple as the plant matures. It has small white flowers with yellow centres, and small berries which turn from green to purple-black.

Birds and rodents eat the berries, which spreads the seeds.

How to control it

Wear gloves and hand-weed plants in your garden or pasture. You can also mow them off if you spot them before the berries set.

Pasture sprays containing Flumetsulam (Headstart, Valdo) or MCPB + Bentazone (Pulsar) do a good job and are clover and grass-safe.

Always seek professional advice and read the product label before using a herbicide.