This August, when the pace of work in Marjorie’s Garden had decelerated, I visited two of my favorite botanical gardens, both in Massachusetts. I spent an overcast Sunday morning at the Berkshire Botanical Garden in Stockbridge, MA, followed by an even soggier Monday afternoon at Tower Hill Botanical Garden in Boylston, MA. Despite the inclement weather, including torrents of rain at Tower Hill, each of these gardens contributed significantly to my continuing education as a gardener. In this column, I report on discoveries at Tower Hill. Next week’s column will cover my visit to Berkshire Botanical Garden.
Herbaceous Perennials for Sun and Shade
The genus Rudbeckia contains a diverse group of summer garden perennials, including R. fulgida var. sullivantii ‘Goldsturm’, a bright orange-petaled coneflower that has become the poster child of American perennial borders. I think that it has been used to the point of boredom, often in mass plantings with ornamental grasses.
And so it is refreshing to discover other members of the genus used creatively in gardens, including R. submentosa ‘Henry Eilers’, a cultivated form of the native sweet coneflower that I found growing in a mixed border at Tower Hill.
R. submentosa is native to Connecticut, New York, Rhode Island, and west to the plains states. Nurseryman Henry Eilers is credited with discovering the plant that now bears his name growing in a railroad prairie remnant of Montgomery County, Illinois. Commercially introduced in 2003, ‘Henry Eilers’ offers a new look in coneflowers. The yellow ray petals that surround the domed central brown cone are tubular rather than flattened as in the species.
‘Henry Eilers’ flowers from July through September on plants that grow to 5 feet tall. At Tower Hill, it takes center stage in the late August mixed border, including a section where it grows alongside a variegated ornamental grass and the lavender blue Russian sage (Perovskia atriplicifolia). The overall effect is very prairie-like.
In a shady corner of a garden surrounding a small building at Tower Hill, the large maple-like leaves of yellow wax bells (Kirengeshoma palmata) serve as a foil for the bright yellow, drooping, waxy, bell-shaped flowers that first appear in late June. The bold dark green foliage arising from purplish stems creates a shrub-like habit that is considered by many to be the dominant ornamental feature of this Asian perennial. Personally, I like to be there when it flowers.
Seeing the yellow wax bells at Tower Hill reminded me of my visit to Berta Atwater’s garden in Little Compton, Rhode Island, in August of 2012. Her shade garden, planted to create striking scenes based on the color and texture of foliage, includes a large expanse of K. koreana, closely related to K. palmata with similar striking foliage. She combined the yellow wax bells with the variegated foliage of Japanese forest grass (Hakonechloa macra ‘Aureola’), a beautiful contrast of foliage texture and color that far outlasted the period of bloom.
New Forms for Old Friends
Pendulous cultivars of two trees native to the eastern United States, both hardy in New England, grow in the borders at Tower Hill. One is Cercis canadensis ‘Covey’, a small weeping cultivar of the common redbud that grows in USDA Zones 5-9, including Marjorie’s Garden. The lack of an upright leader results in a dense umbrella-shaped crown of arching branches. When staked it may reach 10 feet in height, but if not staked it seldom exceeds 5 feet in height. In all other respects, ‘Covey‘ resembles the species with clusters of lavender-pink pea-like flowers in early spring before the heart-shaped leaves emerge.
I did a double-take when I rounded the corner of an island bed to discover a weeping form of bald cypress, Taxodium distichum, a deciduous confer that grows well over 100 feet tall in the cypress swamps of South Carolina, my old stomping ground. The cultivar ‘Cascade Falls’, however, tops out at between 8 and 20 feet with a spread of 5 to 8 feet (USDA Zones 4-9). Its branches hang outward and then plunge to the ground. It would be worth a trip to Tower Hill in late October to see this unique tree’s golden fall needles before they drop to the ground.
New Ideas for the Vegetable Garden
Between thunderstorms, I made a quick tour of Tower Hill’s vegetable display garden. Among the many interesting plants there, I ran across “Indigo Rose”, a purple 2″-diameter tomato. On close inspection, I noticed that only the portion of each fruit that received direct sunlight was purple while shaded areas were green. Sunlight enables the production of anthocyanins, the source of the purple color in these fruits and others, including blueberries.
Bred by researchers at Oregon State University working with wild-type tomatoes, “Indigo Rose” is the first garden tomato variety with high antioxidant levels in the fruits, a direct result of the high anthocyanin levels. I’ve since learned that seeds of this 80-day open-pollinated tomato variety can be purchased for next year from Johnny’s Selected Seeds, Territorial Seeds, and other seed companies.
The garden designers at Tower Hill went all out this year to bring bold color into the vegetable garden. For example, colorful “ladders” were used for supporting tomatoes and other plants. Hinged together at the top, they seem easy to construct, a great project for the winter months.
I was also interested in the use of onions and other vegetable crops as borders around other crops. For example, Allium fistulosum ‘Shimonita’, a Japanese bunching onion with a short, stout stature and sweet flavor, was used to surround a bed of okra and chard . The foliage is also edible, fleshy and tender with a sweet, mild flavor. In another bed, leeks surrounded an interplanting of beans and carrots.
A rainstorm drove me inside Tower Hill’s main building for a late lunch at Twigs Cafe. Tripod-mounted camera propped against the table, I ordered a smoked turkey sandwich with fresh cucumber slices, homemade potato chips, and coffee. I ate slowly, gazing out a windowed wall at raindrops splattering the abandoned terrace. Just beyond the terrace, a Colorado blue spruce stood tall against the slate-gray sky. On the wall to my left, above three portraits of colorful garden plants, were large block letters: “PLANTS PROVIDE ALL THE AIR WE BREATHE, AND ALL THE FOOD WE EAT.”