Posted: 30/06/2016 at 09:11
Hi Marie35 - thank you for your message. If, as you say, there are a lot of raspberries in your new garden, then I'm pretty sure that's what the leaves with spikey stems appearing in your lawn are.
Get some weedkiller containing glyphosate and paint it onto the leaves avoiding the grass. Leave them until they have gone brown and died off before removing.