This month’s weed of the month (WOTM) is Blackberry Nightshade (Solanum Nigrum)
What is it?
Blackberry nightshade is part of the Solanaceae family that also includes tomatoes, eggplant and capsicum.
It is probably native to Europe and is now widespread and very common in Australia. It is one of Australia’s worst weeds of intensive agriculture.
What does it look like?
Blackberry Nightshade is an annual or perennial soft-wooded, erect herb or small short-lived bushy shrub to 1m high. The leaves are 2-7.5cm long, entire or very shallowly lobed. The flowers are white, in short-stalked clusters of 4-12 flowers. Each flower is star-shaped and about 10mm across with 5 spreading white petals. The succulent, globular berries are usually 6-8mm across, at first green but becoming dull black at maturity. Each berry contains 25-35 seeds about 2mm long.
Why is it a problem?
It is a common weed of horticulture, gardens, crops, pasture and waste land. It is readily spread by birds into bushland and flowers for much of the year. Up to 178,000 seeds can be produced by one plant.
It competes vigorously for space and nutrients, especially in Solanaceae crops such as tomatoes. It is known to be host to numerous nematodes, fungi and viruses that are indirectly a threat to associated crops. Its green fruit and leaves may at times contain toxic alkaloids.
What do I do when I find it?
Pull it out, bag and bin it.
The entire plant is considered toxic however ripe berries are usually harmless. Eating green berries may cause headache, nausea and mild stomach upset. It is extremely toxic to horses.
References
http://www.weeds.org.au/cgi-bin/weedident.cgi%3Ftpl%3Dplant.tpl%26state%3Dwa%26s%3D%26region%3Ddl%26card%3DH74
http://www.herbiguide.com.au/Descriptions/hg_Blackberry_Nightshade.htm
https://www.health.qld.gov.au/poisonsinformationcentre/plants_fungi/blackberrynightshade.asp