How to Grow Asparagus in Raised Beds -- never thought of this; might help not only with drainage (needed) but with weeds (always a problem in asparagus feds) and would also be beautiful ferny look as plant matured through season...hmmmm
"Royal Empress Tree...grows 15-18 ft./year. Empress Tree Facts Grows up to 10 feet or more in the very First Season! We have seen some grow as high as 20 feet.Explodes with rich lavender flowers that look like Orchids but smell like Jasmine. Grows as far north as Canada and as far south as Mexico.
Use cement blocks to edge a garden, and fill the blocks' holes with soil and plant to finish -- low-growing plants like creeping thyme, moss roses or strawberries work well and will not grow high enough to shade or otherwise interfere with garden plants.