Ed Snodgrass is best known for the green roof plants he grows at his nursery in Maryland and his green-roof consulting around the world. After first visiting his “farm” in 2016, I declared the garden shown here the most beautiful stormwater management solution. I’d ever seen, (The design of which is chronicled in an Allen Bush post.)
Ed invited me to visit recently and as always, there was lots to see because he’s cutting edge when it comes to innovations in sustainable landscaping, and upon arrival I saw that his rain garden is a huge success.
Ed tells me the garden has been very little work these last three years, having filled in quickly from plugs and planted in masses – “big swaths!” Some of the original “poor plant choices” required most of the work in early days, but those plants are long gone.
If you read my low-maintenance design tips from Henry Mitchell, you may remember his warning not to use gravel. So I had to ask and learned that Ed used a ground cloth under the gravel, and since he installed it in June of this year there have been no weeds. “Don’t put gravel on soil,” he warns. (What weeds may appear he’ll zap with a steamer – more about that below.) Here the gravel and stones replace plants that never grew together, but Ed says he loves the negative space and the boulders as accents. Me, too.
Close-up of Rudbeckia deamii, the species, with cardinal flower and blue mistflower.
Obedient plant and Datura.
Ed says his general rule with green roofs, including this one, is that they’re a lot of work for the first six months or so, after which you “work diligently for 2-4 years and then you’re really in pretty good shape.”
This demonstration green roof had changed a bit since my last visit. In May Ed sprinkled seeds of orange Cosmos among the sedums, and the purple Liatrus microcephala were blooming. I’m definitely sprinkling Cosmos seeds among my groundcover sedums next spring – more bees, please!
Here’s another good green roof plant, seen here growing right over the asphalt driveway – Phyla nodiflora. Ed says it attracts “every insect in world” and is a great plant to plug into existing lawns. The idea is to “beef up the lawn rather than get rid of it wholesale.” Though not evergreen, it still stands up to turfgrass, and also does well in meadows. 
Above and below, examples of unusual uses of sedum. Love them! 
An exciting discovery for me were the Seven Son Trees on the farm. Introduced in the ’50s and ’60s after breeding work by Harvard and the National Arboretum, they were the “hot tree at Chelsea” this year. The species, like the ones Ed grows, grow to 15-20 feet and there’s a 10-foot-tall cultivar “Temple of Bloom” now on the market. Their height can also be reduced by cutting them back hard.
What’s most exciting about the tree is the astounding number of “bees, butterflies, flies – everything!” that it attracts. So much so that Ed loves to stand right under it to experience the sound of all that buzzing. But it’s also super-adaptable, thriving on very tough sites. It’s never seeded in the 20 years he’s grown them, so not likely to become a pest.
Ed shares the assessment that this would be a great substitute for the ubiquitous crepe myrtle, which supports fewer insects.
A close-up of the Seven Son tree. Ed gave me one that he’s growing for others and I’m excited to add it to my tiny front-yard pollinator garden.
Continuing my tour of the farm, I learned that in the afternoon you can walk among these coneflowers and see dozens of goldfinches scatter. Damn – I was there in the morning and missed the show.
I also love this Bigelowia nuttallii (Nutall’s Rayless Goldenrod at Mt. Cuba). Ed says it’s an important plant for conservation because it’s “great on marginal land and rock outcroppings.” Native to the Southernmost U.S. it’s threatened in some places, so a “good thing to plant because its populations are declining.” It supports “insects that you don’t see at other times of the year.” 
Sedum rupestre in the foreground.
A whole row of hoop houses are named for female blues musicians.
Groundcovers nicely potted-up,
The farm offers preselected mixes like these, or custom blends.
Gabion cages have all kinds of uses in the landscape (I’ve seen them as seating walls) but wildlife-wise, they create excellent habitat for insects. 
Here’s some of Ed’s 70 acres of Solidago canadensis, the result of a 40-year meadow project. It and the milkweed are tough enough to have reduced the invasives substantially. Now the real problem is only where meadow meets the woods, where he still has honeysuckle, sumac, et cetera to contend with. 
Large stand of Berlandiara texana, a “nice dryland perennial in the aster family. These southern plants may be our plants in the future.” For now, they’re sure covered with insects. 
Ed’s Steam Weeder
The last time I visited, Ed was using a flame weeder, but he’s switched from fire to steam as his preferred alternative to herbicides. “We’ve loved it! The flame weeder was more expensive and dangerous to use.”
Ed says the main market for this product so far has been small towns in Maine, using it in their public gardens. They’ve been able to stop displaying “poison” flags, and kids can play there right away. He’s seen it used in Australia (where fires are treated as particularly threatening), mounted in front of tractors that are driven along roadsides. 
The machine kills weeds at the root and the first 1/4″ of soil is sterilized with saturated steam. Click to watch Ed’s videos about using it.
Ed’s Mapping his Farm’s eDNA
Here in Ed’s living room, he showed me the Nature Metrics app he’s using to analyze water samples from his property. The London-based lab then displays species-level data about animal life on the farm – birds, amphibians, mammals, etc – the size of each dot indicating how many were detected of each.
From the company’s website: “Powered by ground-truthed biodiversity data at site-level, eDNA provides an unrivaled picture of a site’s biodiversity, enabling the most comprehensive view available of the full spectrum of life, no matter how hard to detect.”
I sure don’t understand how it works, but here’s how Ed uses it: “Once you know you have habitat for that particular group [of animals], you can try adding a plant or changing a growing condition so as to fill out the missing nearby species, knowing that I already have a similar species.”
eDNA analysis of Ed’s farm.
He hopes the word will spread because the more it gets used, the better information the app will have. Currently only half of the DNA is down to species level.
Ed’s Criminal Jam-Making Enterprise
At the end of another great visit, I was sent away with not just a potted-up Seven Son Tree (which was discovered by bees in mere seconds after I sat it down on my patio) but also this jar of Ed’s “Felony Jam” of apple, blueberry, currant. lemon, peach, raspberry, pear, strawberry and aronia. It’s quite tasty but best of all, it’s illegal! Who knew that it’s a “federal crime to sell jam made from a combination of more than five fruits”?
Ed declared it a GardenRant-worthy jam and I agree.