Various publications have described this grass - common couch, Elymus repens - as 'the worst perennial weed in the world'. There are plenty more contenders for this dubious distinction but there's no doubt that couch has an incredible ability to infest cultivated land very quickly, thanks to underground creeping rhizomes. One plant can produce five metres of rhizome in a season and if this is broken up every small segment can produce a new plant, so cultivation makes the weed problem worse unless every piece of rhizome is removed.
Couch grass rhizomes have sharp, hard-tipped points and on several occasions I've dug up other plants whose roots have been speared through by couch rhizomes. It even penetrated the butyl liner of our garden pond.
Timothy grass Phleum pratense, which produces these lovely cylindrical flower spikes in late July and August, is very similar to meadow foxtail Alopecurus pratensis, but that flowers much earlier, in May. Timothy is a very variable grass - some strains produce a lot of leaf and are long-lived, while others have a tendency to flower quicky and die - but it is an excellent grass for nutritious hay production. It owes its common name to Timothy Hansen, a farmer who popularised the plant as a source of fodder, but before that another American farmer, John Herd, had also recognised its value for cattle and horse grazing and it was also known as Herd's grass. Before Hansen's day it was known in Britain as meadow cat's tail.