Going Vertical in the Mary Livingston Ripley Garden: Year Two!

Last year I tried out a new thing in the Mary Livingston Ripley Garden – growing a green wall!  Like all things the first attempt is often a learning experience. Happily, last year’s wall turned out well enough that I decided to repeat it again this year.

The 2014 Ripley Garden green wall. My first attempt at growing vertically in the garden.

I’ve received many questions from garden visitors regarding the construction of the wall so I thought I would share how it was built. This is by no means the only way to grow a green wall, just my own experience with the project.

I started by selecting frames specially designed to hang vertically. The individual cells or containers of these frames slant downward to minimize soil loss. Last year I planted the cells with things like Creeping Thymes and Lysimachia nummularia ‘Aurea’ which root in wherever they touch the soil making them perfect in this situation.

Since I can’t do the same thing two years in a row, this year decided to try succulents. I ordered an assortment of succulent plugs (small rooted cuttings) and selected a variety of plants we were already growing at the Smithsonian Gardens’ greenhouses to augment the purchased plants.

To begin, I filled all of the containers with a well-draining potting mix and laid them out flat on a table to plant. I really was looking for dramatic color and texture in this year’s wall so I tried to “paint” with the plants by creating patterns through my placement choices. After I finished planting, I marked each tray with a label so I would know the proper layout when the containers were transported down to the Ripley Garden.

Hanging containers with newly-planted plugs at the Smithsonian greenhouse.

The frames were planted in early March and allowed to grow flat on tables at our greenhouse until the roots were fairly established and the plants had grown enough to start holding in the soil. This took about four months due to my plant selection and the fact that I started with small plugs.

(L) The containers after about four months of growing time at the greenhouses. (R) Containers waiting for installation after arriving outside the Ripley Garden.

Hanging the containers was fairly simple. Each tray came with a metal cleat to attach to the hanging surface, in this case the Ripley Garden fence. My co-worker and mechanical mastermind, Rick, helped me run two-by-fours along the fence and then attach the cleats. Since I decided to do three rows of the frames, we spaced things accordingly.

Next came the fun part – installing the trays! The back side of each container had an indentation which allowed us to hang the containers directly on the cleats. We could have stopped there, but we wanted to be sure the containers would not fall off so Rick ran a screw through the side of each tray. We started adding the trays from the bottom and continued to fill each level, adding a screw to each tray. It took less than 30 minutes to install the trays once the cleats were in place. To hide the hanging hardware, we reused some bits of twig screen we had left over from last year’s garden holiday decorations.

The frames were easy to assemble. Here Rick works his magic.

Now that the wall is up, watering is a bit of a challenge. It is possible to purchase little water boxes that sit on top of instillation and allow water to slowly trickle down through the wall. I found last year, however, that watering this way did not provide enough moisture to the lowest row of trays. This year I’m watering by lightly misting the wall with a fine spray of water and taking care not to disturb the soil and cause it to fall out of the containers.

The finished product!

I’ve found growing a green wall a fun experiment, but one that does require more skill and attention than growing things horizontally. But hey, why not try something different!

I really like the way it turned out and hope it lasts through the season. Since I used non-hardy succulents, the wall will be taken down in the late fall and returned to our greenhouse where it may undergo a new transformation for next year!

-Janet Draper, Mary Livingston Ripley Garden Horticulturist