By Pamela Doan
Lori Chips changed my ideas about hypertufa trough planting.
At a workshop at Stonecrop organized by The Garden Conservancy, the author of Hypertufa Containers: Creating and Planting an Alpine Trough Garden recently demonstrated the art and practice.
I was familiar with hypertufa troughs and had seen a demonstration of how they’re made. My perception was that it took a bit of work but looked interesting and might be an addition to a container garden. I didn’t see their potential as unique to alpine plants. I learned from Chips that, at their best, hypertufa troughs mimic the planting conditions of rocky, mountain sites and allow a gardener to create vibrant landscapes with tiny plants.
Let’s start with the vessel and move on to the plants. Hypertufa is a handmade container made from portland cement mixed with peat moss, coarse perlite, water and fiber mesh. Anyone can make their own as a half-day project and hypertufa containers are sold commercially, too.
Chips, who is the alpine plant specialist at Oliver Nurseries in Fairfield, Connecticut (I recommend the online tour or a visit, it’s beautiful!), traces the popularity of hypertufa containers to a time in England when stone troughs and sinks were replaced with metal and ceramic and people appropriated the stone for planting. “There weren’t enough to go around and hypertufa was invented as a substitute,” she says. Hypertufa is similar to tufa, a rock that’s formed in waterways when minerals build up around organic matter.
While you can find instructions on the internet for mixing your own hypertufa, Chips’ book has detailed information finetuned through experience; if you’re going to spend a few hours mixing fancy cement, take lessons from a pro. Once your materials are combined, the hypertufa is set into molds created from boards or other firm materials.
Hypertufa troughs breathe better than stone and don’t heat up like other materials. “It’s a porous substance and frost resistant,” Chips says. “You’ll have better luck growing tiny alpine plants where they aren’t native.”
The joy of making your own hypertufa container is the chance to be creative with shapes and forms that invite close observation of a palette of plants. Chips says to consider the plants you want before choosing a shape and to make the container at least 8 inches deep.
Chips also shared curious facts about alpine plants — which grow above the timberline or in other similarly harsh conditions with rocky soil, strong wind and high UV light — that made me understand why these plants are so appealing to gardeners.
Alpines are known for evolutionary tricks that help them survive on mountainsides. The flowers grow close to the leaves, not usually on stems or stalks. The acaulis species epithet means “stemless,” and denotes some alpine plants, e.g., Gentiana acaulis and Stenotus acaulis. The flowers also tend to be large for the size of the plant, which attracts the fewer pollinators found at higher altitudes.
Hypertufa troughs work in sun or shade. “The only limitation is your imagination and making sure the plants’ needs are met,” Chips says. While hypertufa is a cold-hardy container, in winter she advises that it should be protected from high winds and scorching sun. “An open north, northeast or northwest setting is ideal so it’s not getting the harshest exposure,” she says.
Chips calls this her list of “bulletproof” plants that would be the easiest for beginners. Many alpines are native to the U.S.:
Armeria – seathrift
Shade planting-dwarf Astilbe, Hosta, ferns
Sempervivum – hens and chicks
Saponaria – soapworts
What not to plant? Well, this is your choice, but to stay true to the form, annuals would be a waste of a cold-hardy trough and non-alpine plants wouldn’t capture the intention of the style.
“What you’re trying to achieve is for the viewer to suspend disbelief and be in that little environment for a moment,” says Chips. Resources from the North American Rock Garden Association (nargs.org) can help you get going, too.
Pamela Doan, a garden coach with One Nature, has grown ferns in Seattle, corn on a Brooklyn rooftop and is now trying to cultivate shitake mushrooms on logs. Email her at firstname.lastname@example.org.