Dr. Leonard Perry, Horticulturist in Residence
A question I have often received over the years is “what can I plant for late season color?” The problem, I realized, is that many gardeners buy their flowers early in the season, so have predominantly early-summer blooms. When I started at North Country garden, I was always busy early in the season, finally getting somewhat caught up by August, so I went to nurseries then to buy perennials. Getting ones in bloom, my garden was mainly late-season bloomers. Therefore, I eventually started making a point to go shopping earlier in the season and to focus on flowers for earlier blooms. Check out local nurseries now to see what they have in bloom, or shop now online. Ideally, just make sure to get perennials in the ground by the end of September, preferably by mid-month, to make sure they have some time to be rooted before the ground gets cold enough to stop root growth.
On a recent visit to the King’s Garden (which has a stunning display, thanks to Rose, Garden Foreman, and her team), four flowers particularly stood out to me for their show or unique growth—two annuals and two perennials.
Salvia ‘Lady in Red’ has been one of my favorites for some years (it was an All-American Selections winner in 1992), and this year lined the walk on either side as you entered the King’s Garden through the gate on the fort side from the maple allee. This red-flowered salvia reaches 2 feet or slightly taller, and has red flowers through the season. It is different from the common saliva most know (Salvia splendens), being a different species (Salvia coccinea)—the species name meaning “red.” It will grow with some blooms in part shade, but has best flowering in full sun. It can tolerate dry soils once established, and does not like wet soils.
The spikes, up to a foot long on ‘Lady in Red,’ of small red flowers are very attractive to hummingbirds and butterflies—hence another common name of ‘Hummingbird Sage.’ Goldfinches and other small birds like the seeds. There is a newer series of similar salvia—the ‘Summer Jewel’ series, but I find ‘Lady in Red’ is as good, or often better with more flowers, than ‘Summer Jewel Red’ (a 2011 All-America Selection). The species is native to sandy areas such as in coastal plains, through southern states west to Texas and Mexico. It is often called ‘Texas Sage.’
A second annual flower that is found spilling out onto a walk in the King’s Garden, near the Pavilion, is nasturtium. For many, including myself, this has been a great year for this vining or trailing flower. There are several cultivars (cultivated varieties) of this flower, some spreading (Tropaeolum majus) and vining and others more bushy (T. minus). This flower has been around for many years, and was a main flower used by the artist Claude Monet at his home in Giverny, France on each side of the main allee (giverny-impression.com/nasturtiums). They love to hang, so they are best seen growing on berms or raised pots and containers, such as window boxes. A great example of this can be seen each spring at the Isabella Gardner Museum in Boston, where they start them almost a year prior at the April opening, where they hang up to 20 feet down from window boxes for a few weeks of blooms (www.gardnermuseum.org/experience/courtyard/nasturtiums).
Nasturtiums prefer full sun for best flowering, but will grow in part shade. They prefer soils that are cool and moist, but not soggy. They have round leaves an inch or more wide, held on long leaf stalks. The attractive flowers are on inch or more wide, with five flaring flower parts, and come in several colors. Flowers are popular as an edible plant part, especially to decorate salads, with a peppery flavor. They are high in vitamins A, C (10 times that of lettuce), and D.
Trailing cultivars you may find include the ‘Jewel of Africa’ mix with flowers in yellow, red, cream and pink. ‘Moonlight’ has pale yellow flowers, while ‘Apricot Twist’ has double flowers in apricot-orange, splashed with red. Bushy, semi- to non-trailing cultivars include the popular ‘Empress of India’ with bright scarlet flower—a nice contrast to the blue-green leaves. ‘Peach Melba’ has cream flowers with a raspberry red center, ‘Strawberries and Cream’ has pale yellow flowers with splashes of red, while the ‘Whirlybird Mix’ has semi-double flowers in cream, salmon, gold, and cherry-rose. Look through seed catalogs this winter to find many others, which can be easily started at home from seeds next April.
A couple of less common perennial flowers in the King’s Garden stand out during the end of summer each year. Inside the walled garden on the more shady, southeast side, you will find ‘Waxy Bells,’ or yellow wax bells (Kirengeshoma palmata), named for its yellow waxy bell-shaped flowers that are drooping in clusters. The scientific name comes from the Japanese for yellow (ki), lotus blossom (renge), and hat (shoma). The species name refers to the palmate (palm-shaped) leaves, similar to a maple. ‘Waxy Bells’ is native to Japan, Korea and northeast China.
Plants get three to four feet high, and a bit less wide. They need part shade-to-shade, and moist soils. Hardy to USDA zone 5 (-10 to -20 degrees minimum in winter on average), they have a nice protected setting within the King’s Garden wall, which also gets some temperature moderation from the lake nearby.
The other perennial that many visitors notice and inquire about in late summer is the ‘Cup Plant’ (Silphium perfoliatum). This you will find growing outside of the walled garden, in the children’s garden in full sun. This native of eastern North America is generally six to eight feet high, and three feet or more wide. The yellow, daisy-like flowers mean it is in the composite or aster family like the sunflowers. Similar to these, they are attractive to butterflies and birds (for the seeds). Flowers are held on top on long stalks in clusters, above the large leaves, which come together around the square (in cross section) stems to form a cup. These cups are the plant’s means of collecting rainwater. It grows best in moist to wet soils, but is quite adaptable. The stems, when cut, exude a gummy sap. This gives rise to another common name of ‘Cup Rosinweed.’ If you have a prairie planting or one of native plants, or back of a border with plenty of room, consider this quite hardy, USDA zone 3 perennial (surviving to -30 degrees F in the winter).
Happy gardening and be sure to come visit our late season blossoms in the King’s Garden!