Can anyone tell me what weed this is. It is growing in patches over my lawn. It weaves its way through the grass, has pink flowers, and a large tap root which makes it a pain in the proverbial to remove.
I'm not 100% sure, but if the things have some thorns they could be suckers from a moptop (Robinia). We have suckers from nearby Robinias that pop up and they look and have similar characteristics to the weed you have described, I can't however verify the flower characteristics. If they are Robinia suckers they should be controlled as they can be very invasive and appear some distance from the parent tree.
Sorry Andrew – I tried a “plate solve” with The Sky and entered the RA/Dec coordinates of your back garden but The Sky couldn’t find a match for your weed nebula! LOL!
Andrew can you take another photo but this time put a 20 cent piece in the shot as well so I can get an idea of the size of the leaves and flowers. Also a close up of the flowers and where the leaves join the stem would be good as well.
Sorry Andrew – I tried a “plate solve” with The Sky and entered the RA/Dec coordinates of your back garden but The Sky couldn’t find a match for your weed nebula! LOL!
It is spreading across the lawn next to the pool Dennis, try the region around the Lagoon nebula.
Andrew can you take another photo but this time put a 20 cent piece in the shot as well so I can get an idea of the size of the leaves and flowers. Also a close up of the flowers and where the leaves join the stem would be good as well.
20 cents!! I don't carry that kind of cash around. Luckily I was able to raid the kid's piggy bank and found one.
Here are some more pics. The 5th pic shows it spreading across the lawn (the dark patches).
It looks like it might be one of the Medicago sp but the flower is the wrong colour and the inflorescence doesn't look quite right. Has it set any seed pods? If it has are the pods spiney?
edit: On second thoughts I don't think it is. Medigaco has trifoliate leaves not pinate with 5 or more leaflets.
I've been going through my books without success. I need to have a piece of the plant in my hand to check out morphological characteristics so I can key it out.
Pm me Andrew if your interested and I'll send you my address and you can send me some pieces.
It is definitely a member of Fabaceae (the legume family), which doesn't help much as there are 12,000 species in it (including all the suggestions so far. It doesn't look like Medicago, it's definitely not Robinia suckers and I'm not convinced its Swainsonia (not enough leaflets, flower panicle is too dense).
If it is growing as a vigorous weed it may well be non-native (perhaps South African?) and thus not in Australian 'wild flower' type books. FWIW I am a botanist, though a physiologist so my taxonomy is limited and coming from the UK originally, it is even more limited when it comes to Australian plants. Doesn't look European though.
Sump oil and diesel would probably work, but getting something to grow there afterwards might be a problem if too much is used, especially if the plant covers a large area.
If you are keen on getting rid of it and don't feel up to digging it up a mixture of Kamba M (relatively low toxicity) and a couple of DROPS of dishwashing liquid should do the job. It's less toxic than the 2,4, D derivatives and will also no harm the grass. But no matter what you get, Read The Label. ( Sorry The Hort teacher coming out in me )
...boiling water can safely kill weeds, if the logistics suit.. also an overdose of urea will kill the weed, then feed the grasses to invade the 'burnt-patch'