My internet search brought up all sorts of weedwackers, but it sounds like perhaps what you are thinking of has wheels? I have a small battery powered weedwacker with an optional wheel that I love, but I've never heard it called a strimmer.
Wikipedia re-directed me to 'string trimmer,' defined as: A string trimmer, also called a "weed-whip", "whipper-snipper", "weed-whacker", a "weed eater", a "line trimmer" (in Australia) or a "strimmer" (in the UK and Ireland), is a tool which uses a flexible monofilament line instead of a blade for cutting grass and other plants near objects, or on steep or irregular terrain. It consists of a cutting tip at the end of a long shaft with a handle.
I've also never heard of a whipper-snipper, but like the sound of it!
(Of no particular importance -- I don't use Google as either a search engine or a verb.)
