Through a friend of a friend I came upon the blessing of some free stone. It seems Tom had just completed work on his beautiful home and had quite a bit of scrap stone left. Most of the stone was small and irregular, but it was also free. I collected as much as possible in the time I had available but what to do with it? I love stone, it is attractive, incredibly low maintenance and wherever you put it in the garden you never have to weed again...but I can't just pile a bunch of stone in my garden....or can I? After unloading and staring at the stone for some time I came up with the concept; let's build some nice bottomless planters for the garden. Lots of visual impact, lots of stone and it will make some decent dents in the places I need to weed in the future. If you don't have a friend of a friend who just built a house look towards friends in the construction trades. Frequently when houses are built scrap stone is simply discarded often buried at the build site itself. Being friendly to crews when they are finishing up may just score the scrap stone you need to make this project.
I'll be building several of these so picking out the general placing for each is important. For me I was looking for areas my other plantings weren't thriving so as not to lose anything in the build. Luckily I have three fairly equidistant bare spots so that will work just fine.
The next step is to clear the mulch and level the area. We will need about two to three feet of cleared area to work. My garden has a tree in the middle so everything has a bit of a slope to it. We aren't laying precision masonry here so skip the bubble level and just eyeball it.
We will be using an eight inch concrete form tube as a guide, and just to be somewhat consistent from planter to planter lets mark a height gauge on the tube. I chose a height of nine inches and used a marker to draw a line completely around the tube.
Place the tube directly in the center of where the planter is being built and support it in place with some of the larger stones. Try to snug them in place and ring the base of the tube as much as possible. The stones should be reasonably level with each other.
Take some mortar and finish a rough level on the stones. This isn't precision stuff, just fill in some of the more egregious gaps but keep the mortar somewhat close to the tube, we don't want it slopped out everywhere. This process is only done on the first row of stones.
Stones other than the base should be "back buttered" and put in place. When you back butter a stone it simply means putting the mortar on the stone itself instead of the base you are putting it on. Dry fit a stone first to find the best placement then back butter and tap it in place. Make sure you smear the mortar on the back of the stone so as to assure its adhesion to the stone before you place it. Don't push too hard when you put a stone in place, we don't want the mortar squeezing out as it provides quite a bit of stability for the planter and can look sloppy if it squirts out the cracks.
Continue to mortar and place stones reducing in size as you build upwards. Try to place as many as possible with the center covering the crack between stones below it, like laying bricks. Unlike laying bricks your stones are irregular and won't likely line up in nice even rows, this is actually good, don't stress, it will add character to the planter. The only stones you need to worry about being (mostly) level are the top row as these will be much more visible. Once the planter has been built to height (don't worry if its a little over or under your line), carefully remove the tube. Use the remaining mortar to coat the inside of the planter walls carefully filling the gaps and spaces between stones. This will reinforce the planter and give it some ability to hold moisture for the plants. Do not coat the bottom of the planter as this would restrict the root growth of the plants inside.
Below is our completed planter. Just let the mortar dry and cure over the next day or two before filling. At this point you can go ahead and scoot the mulch back around the base.
After letting the planter cure for 24 to 48 hours, put some fertilizer or bone meal in the bottom, add some potting soil and plant appropriately.
The plant I chose will grow to about 12 inches wide which will eventually spread over the top nicely. I have three of these planters that visually break up a rather large garden and give it some character. Adding a few spare stones around the base increase that character and the contrast of the light stone against the dark mulch bed give an incredible pop sure to be noticed.