I have just started putting in a native garden in my front lawn. The lawn is very well-established Kikuyu. I removed a 70x50cm rectangle of the sod with a square spade for the first plant. It was very time consuming, and looking at the rest of the lawn I’m wondering about a more efficient way to do it. I hear a non-selective herbicide like Roundup could do the job, but I don’t know much about how these poisons work and am a bit concerned about damage to soil nutrients, killing beneficial bugs and other unwanted side effects since the poison binds to the soil and doesn’t break down for years. Am I worrying about nothing?