Morning gardening grandma. Yep loads and loads of mistakes. The temptation to plant things I "liked" but without any regard to whether they were suitable or not. Now, I try to give the right conditions to each plant so each one,thrives. Impatience so cutting corners always causes problems so now I try to take the time to think a little more. That part of the garden is prob 10 years old and it really is very low maintenance. Right now it's full.of hellebores but when these are over that summer picture emerges, with the addition of a few tender perennials. Although maybe costing little more, it's best to plant a few quality plants than a load of cheap space fillers..viz., If there's a plant you want look at the varieties and get the variety you really want.....e.g. Don't just get any old astrantia, look at the newer ones and plant one of those so that you get the colour you really want. Better to fill spaces with annuals for a year or so whilst you build up your knowledge of plants, your soil and your comditions. Oh! Dont over plant for one season.....choose good plants to cover all seasons. Hope that doesn't sound pompous....gardening isnt meant to be too serious!