Retaining Walls

Today was another chilly one with minimal activity out in the gardens (if you don't consider all the deer tracks and their unsanctioned activities....). Larry and Bill were here early to make some modifications on our end loader for snow removal and made some corrections out in the lights show. We also have our heaters going in the koi pond now to keep some open water for oxygen exchange for the fish. I had a staff meeting and worked on lots of odds and ends. Jenny came in to start entering information for our new plant signs. She put in both woody plants and started on our fern collection as well. Dr. Gredler was here restaining benches and both Urban and Rose continued on the next coat of yellow paint on our culvert planters. Maury, Dick P. and Tom C. repaired some lights over in the gift shop and Maury then ran some errands for me; including getting some blue paint for future endeavors....We also saw Dave E., Big John, Mary W., Jim, Bill, Julie G., Jason and Mike M. at the horticulture center.

If you are interested in contracting, building or repairing retaining walls, do some research or seek professional help prior to diving right in to the process. The intent of mentioning retaining walls in this blog is not to explain their constrution but to showcase their merit and the wide range of materials and styles that can be used to deal with grade changes and slopes. Well constructed retaining walls can be a wonderful asset in a landscape where changes in elevation are a consideration and/or desired. Proper placement of these walls can create level terrace areas for planting, minimize erosion and certainly eliminate dangerous maintenance areas where using a mower or string trimmer is frought with peril and potential injury. I've seen as many good (sound) retaining walls as I've seen failing (unsound) walls and the difference, while sometimes related to materials (and certainly $), really is commesurate with understanding the forces involved with RETAINING soil and significant weight. We can all purchase the materials (lumber, railroad ties, pre-fab block, flagstone, etc.) to build a wall but understand that when a wall goes over 3' tall, there are more considerations and the dynamics of proper construction increase exponentially. The third photo down shows a timber wall that I walk my dogs by every day and have observed the continued "battle" that will eventually conclude with that wall failing and needing to be replaced. While some of these walls are quite fancy and expensive, the overall design intent and function is identical.

The block wall below defines our upper terrace garden with a 4.5' drop to grade where you see the road to the right. A wall like this includes an interlocking pin system and the use of adhesives. The materials of a retaining wall are a consideration but so is the lower stability of the wall which frequently requires compacted gravel and wall courses underground. Materials that back a wall like this include fabrics and clear gravel to allow water to pass thru and drain away from the wall (not mass behind the wall). This wall actually has perforated drain pipe behind it to vacate excess water under the road. Again, understand all components of a retaining wall, regardless of materials or height. Longevity is an obvious goal for any of these walls.