I found an old fountain basin years ago and have always used it outside with a fern in it. I have decided to bring it in and create an indoor arrangement. The bottom was jagged and needed to sit on something to sit up right. I painted an old plant saucer grey to set the basin in and under that I placed a scrappy looking piece of wood. I planted everything in a bowl, inside the concrete basin with 1/2" gravel in the bottom. The gravel will help the plants drain (discount dollar stores sell small sacks of gravel for $1 - 2). When the plants run their course, I can just remove the plants and replace with something else. The concrete basin is quite heavy. I wanted to lighten the "garden" by elevating the bowl with a couple to-go boxes placed inside the basin. Just enough height to make the top of the bowl even with the basin top. I covered the soil with moss, but one could use stones or small pine cones.
The results were nice. I chose small inexpensive plants with an orchid for the height. I have been able to find orchids for as little as $15 at the grocery store.
Using floral foam (Oasis), I soaked overnight in my sink, I have created the perfect host for some Japanese Boxwood cuttings. Cut the soaked foam with scissors to create a better shape. Snip the bottom to fit into the container. Many of the vintage vases I have used often have undetectable cracks in them. This creates a mess when they leak. Line the container with a tub or baggy cut to size.
It takes quite a few cuttings to create a good size topiary. Mine is about 7" across and took over 120 clippings. I have the shrubs in my yard but you could buy a (gallon size) boxwood at your garden center and use clippings from that create your topiary. I begin at the top and work my way around the foam, making a sphere shape with the cuttings. Each clipping is about 3 - 4" long. I remove the leaves from about 1 1/2" from the bottom of the cutting to place into the foam. The foam will break apart if you let the leaves remain on the branch. Fill in the bare spots with additional cuttings. I always trim the topiary to the shape I desire. The results are great!
I have had a topiary last for up to two months. Keep foam wet. You will have to keep them trimmed. Sunny spots in your house will promote the growth much faster than the lower light areas.