I have identified a plant called Cup Plant in my garden. I read conflicting views from 'It's rare in this country' to 'Dig it up now it's very invasive'. I'd be grateful for some advice.
Have you got a photo?
Silphium perfoliatum is native to Connecticut and is a weed in some AmericanStates . In UK it is a large sunflower type plant for the back of a border.
How did you identify it and how sure are you?
Very sure as I compared it to photos on the internet. I know what it is, I need advice on whether to keep it or not, ie is it invasive weed? Grateful for any help...
Whether something is an invasive weed or not,depends on the conditions in grows in. For instance, Zantedeschia dies if left outside in my garden. In Cornwall, it thrives. In the upper reaches of the Swan River in Western Australia, it is a weed and spreads everywhere. How big is the patch now, and how long have you had it?
Only one plant so far but has grown from nothing to 4 ft high in less than 3 months.
Not a weed in my garden. One clump and it has stayed as one clump for the last 10 years. Dead head if it seeds around.