Typically designers use use trailing ground covers to cascade down walls, the most common plant probably being rosemary. But what about something more interesting, something that does not require as much pruning back? Something that will make people stop in their tracks and say, “wow!” Something like, say, orchid cactus (Epiphyllum)?
Epiphyllum, true to their name, are cacti. They hail from tropical areas more jungle than desert, but retain typical cactus traits of water saving, resistance to neglect and colorful flowers. Unlike desert cacti, they’re epiphytic, growing above the ground where they get sun and light – and more regular watering.
Our installations
The first try involved simply planting the cacti at the top of the wall, thinking there would be enough of a built-up mulch layer from fallen leaves. This did not account for the brutal clay soil, something that prevented the plants from becoming well rooted enough to put on rapid growth and develop large numbers of flowers.
The current system uses pots and shallow planters filled with highly organic soil suitable for the plants, held to the top of the wall by stakes hammered through the containers before planting. A drip irrigation – shrubblers or stream bubblers – makes sure the epiphyllums have enough water to thrive. Under this system, we’ve seen good growth, although we won’t really know how well it worked until next year’s blooming season.
Designing your vertical garden
Of course, it doesn’t have to stop with epiphyllum in your design. You can mix in other succulents, such as ghost plant (Graptopetalum paraguayense), Sedum morganianum, and Rhipsalis (an epiphytic cactus). Or rat-tail cactus (Aporocactus). Of these, only the rat-tail cactus has spectacular flowers: the others will create a blue-green and gray tapestry of color year round, to fill in when the cacti aren’t in bloom.
Out of bloom, epis have interesting forms. Combining them with other exotic plants with similar requirements will provide more interest year round. In addition to the plants named above, try them with Schlumbergera (for bloom outside the spring season), and tillandsias. Rabbit’s foot fern (Davallia) could theoretically also work.
growing epiphyllums
The plants like bright filtered sun, regular feeding with a liquid plant food and that’s it. They don’t like being repotted, so once you’ve made them happy you can sit back and watch the show. Eventually the epiphyllums will reach the bottom of the wall, but it’s a simple matter to break off the stems along the ground (after they’ve put out some roots) and pot them at the top of the wall where they can cascade.
Epiphyllums come in a variety of colors from yellow to white to pink to red. The key for wall treatments is to pick varieties that tend to hang downward. They all flower in spring, with flowers produced in succession over time, varying a bit from variety to variety.
People normally get plants in two ways: cuttings from friends and specialists. Ordering from a specialist lets you read about each variety, see what flowers you’ll get in a few years when your cutting matures and above all pick the color and growth habit of your new plants. They’re not expensive plants if purchased as cuttings. Just remember if you buy cuttings or rooted cuttings, they’re not mature, ready to bloom plants – so you’ll have to wait before you see them bloom.
None of these plants tolerate frost, so this only works in coastal California or anywhere the plants are safe from freezing.
Using epis to cascade down walls is somewhat experimental, since the plants are most often grown in hanging baskets to mimic their natural habitat. If you want to be safe – at the price of a longer wait – grow your plants in pots as propagation stock to use for cuttings. This said, as long as you provide appropriate soil, ample light and fertilize when needed, your plants should thrive. Our setbacks were due to insufficient light, wrong soil or broken irrigation emitters – all hopefully corrected in the current growing system.
Our plants cascade down a concrete retaining wall, but there’s no reason they could not be part of a low maintenance green wall or screen, say around a patio.