Unless you’ve been hiding under a piece of concrete, you’ve no doubt heard of our crevice garden experiment, constructed with recycled concrete and plants planted in chipped slate (Permatill). It’s been just over three years since we started the project and just over a year since its completion. In all, the crevice garden spans 300′ linear feet and is built with 200 tons of recycled concrete. The garden has allowed us to grow a range of dryland (6-12″ of rain annually) plants that would otherwise be ungrowable in our climate which averages 45″ of rain annually.
One of many plants we’d killed several times ptc (prior to crevice) are the arilbred iris, known to iris folks as ab’s. These amazing hybrids are crosses between the dazzling middleastern desert species and bearded hybrids. Being ready to try again post crevice (pc), we sent in our order to a California iris breeder, who promptly emailed to tell us that he would not sell them to us because they were ungrowable here. It took some persuading before they agreed to send our order, but on arrival, they became some of the first plants to find a home in the new crevices. Although we’ve added more ab’s each year, the original plantings will be three years old in August. Here are a few flowers from this week.
Iris ‘Aztec Prince’ 
Iris ‘Bold Awakening’ 
Iris ‘Confederate’ 
Iris ‘Glow of Love’ 
Iris ‘Peresh’ 
Iris ‘Refiner’s Fire’ 
Iris ‘Sand Dancer’ 
Iris ‘Sharman’s Magic’ 
Iris ‘Shimmy Shake’ 
Iris ‘Signal Butte’ 
Iris ‘Tresco’s Eclipse’
Iris are just a few of the gems that can be found in our “cracks”, continuing below with dianthus. As we continually take note of our trial successes, more and more of those gems will find their way into our catalog and on-line offerings…as long as we can produce it in a container. Please let us know if any of these strikes your fancy.
Dianthus ‘Appleblossom’ 
Dianthus arenarius 
Dianthus ‘Inshirach Dazzler’ 
Dianthus ‘Razzlepop’ 
Dianthus subacaulis 
Dianthus ‘Vivid Bright Lights’ 
Dianthus ‘White Crown’
If that’s not enough, here are some more shinning stars currently in bloom.
Allium trifoliatum ‘Cameleon’ 
Arenaria grandiflora 
Corydalis flexuosa ‘Porcelain Blue’ 
Crambe maritima 
Delosperma ‘Mountain Dew’ 
Delphinium tricorne 
Globularia meridionalis 
Homothophylla pyrenaica 
Hymenoxys scaposa ‘Travis’ 
Manfreda undulata ‘Crested Surf’ 
Penstemon heterophyllus 
Penstemon triflorus 
Puya dyckoides 
Scorzonera cretica 
Taraxacum pseudoarurem
If any of this seems interesting, you probably should be a member of the North American Rock Garden Society…a group of similarly afflicted individuals. If you are specifically addicted to cracks, check out the nearly 2000 strong, really sick folks on Modern Crevice Gardens on Facebook
The crevice garden is delightful. I especially love the ‘Appleblossom’ Dianthus!
Beautiful!
Excellent post!
Great post of terrific work. But how do you “decrease “ the rainfall for just that part of the gardens?
We found that in many cases, it’s not the amount of rain, but how fast it leaves the root zone. By planting in pure expanded slate, the water runs right through. The first year after building the crevice, we set an all time record of 60″ of rain, so it was a great test.
So if l planted the succulents that go outside for the summer in pots of expanded slate would that work? Better than covering them with plastic sheets. I really appreciate your addressing my “small” situation.
To quote our favorite economist friend, Charlie Hall, “that depends”. Planting in containers is completely different than planting in the ground. Some cacti would probably grow fine in expanded slate in a container, but not most succulents would not thrive in those conditions. In the ground, the roots can reach water hiding in cracks and crevices that simply isn’t available in a container. I’d recommend using a well draining container mix that contains some grit/gravel for extra drainage. A plexiglasss/plastic cover above the plants would actually work well for plants that are particularly sensitive to water. Depending on where the plants are native also affects their tolerance for moisture. Plant from high elevations in Chile, for example, hate any summer moisture. Plants from northern Mexico are often fine with summer moisture, but detest fall moisture. Some mangaves are very tolerant of summer moisture, while others are more sensitive…all dependent on the species involved with the cross. Another option is to stage your container on the south or west side of a tree or shrub, that can keep much of the rain off without affecting the sun they receive. So, it depends?