Flowers at the rock garden

Rock gardens are one of the better places outdoors to find a wide assortment of flowers. They can even change from spring to summer to fall as certain flowers bloom at different times. So it can be really worthwhile to go back every couple of months and try to observe what's different. What types of flowers did you not see the last time? I also like the fact that as far as the ones I have been to, they seem to be a nice place for peace and quiet. Usually winding paths and trees give plenty of places to hide in the shade or avoid the noise you might find in a busy park.