When Engelmann's daisy, Engelmannia peristenia, takes over. In three years one little plant has reseeded and spawned monsters. They are much taller than the roadside plants and, pretty as they are, they have to go. 'Mannia' like zexmania is a good suffix..
Tomorrow morning! I know there is something waiting behind them to take their place. Smaller is better when it comes to rock gardening.