No, but again it can make a very significant difference to the success, especially the species diversity of your perennial meadow. Every species in your mix needs a slightly different set of triggers that allow it to germinate and grow. We formulate the mix carefully to encourage the greatest range of species to all thrive together but it is necessary to check the faster and bushier ones to allow slower and finer ones to get a foothold. At the same time any open soil is likely to start getting colonised by invading weed seeds. Left unchecked, faster growing perennials and aggressive weeds will gain a competitive advantage quickly swamping out others. An establishment cut checks any invading annual weeds and stops the faster growing or emerging perennials from dominating. Essential light and water reaches the slower growing species and allows them to catch up. It also encourages basal shooting which in turn helps to close out bare ground. Once you get to the end of the first growing season and there is a good range of species present they are all remarkably resilient but really do need this initial helping hand.