8. MYASOTIS also known as FORGET-ME-NOT they range in colour from bright blue to pale blue, some tinged with pink, with soft small leaves, and flower in late Spring for about four months Forget-me-nots are about 6 - 8 inches high and quite bushy. They seed themselves abundantly, so they never go away if the position is right for them. They grow in sun and shade. After a few years, they tend to spread and become invasive, but it's easy to control them by digging up unwanted plants.