The main problem facing plant collectors with small gardens is lack of space for rambunctious perennials. In my own little yard, muscular Joe Pye weeds (Eupatorium maculatum, E. purpureum) had to go after a few seasons, as did their companion, Helianthus angustifolius. Canna lily hybrids merrily multiplied, eating up one whole bed before they got the axe (literally). Mountain blue-star (Amsonia tabernaemontana) threatened a beloved Baptisia minor: I moved the Amsonia five years ago, and it’s been in a puny sulk ever since.
One herbaceous big boy has weathered this parade of comings and goings, secure in the knowledge I could never bear to banish it. Native to salt marshes from southern New York to Florida and as far west as Texas, Kosteletzkya virginica goes by several common names: Virginia mallow, swamp mallow, seashore mallow, marsh mallow, fen rose. A member of the Malvaceae clan, its clear pink blooms resemble 2-inch-wide hibiscus flowers, complete with prominent yellow stamens topped by dainty pink pistil crowns. The 4- to 5-foot-high subshrub has large, mid-green, spear-shaped leaves and a 3- to 4-foot spread. A stately presence in the garden, Kosteletzkya’s coarse texture offers the eye a place to rest amid the fussy foliage of lesser perennials.
Common name: Virginia mallow, swamp mallow, seashore mallow, marsh mallow, fen rose
Hardiness: Zones 6 to 11
Mature height: 5 to 6 feet
Mature spread: 3 to 4 feet
Classification: Herbaceous subshrub
Landscape Use: Specimen, perennial gardens, mixed shrubberies
Ornamental Characteristics: Prolific, 2-inch, clear pink, hibiscus-like flowers July to November; pleasing coarse-textured habit; ease of culture and maintenance
My specimen came in a 2-inch pot from Woodlanders Nursery out of Aiken, S.C., back in the 1990s, when they still offered a hard-copy catalog. It’s been a fixture in our garden ever since, surviving in situ numerous plant shufflings, bed reconfigurations and purges. It endures with good grace an occasional root-whacking to keep it in bounds. Kosteletzkya doesn’t require cosseting: Once established, it grows without much in the way of supplemental water or food. It tolerates wet feet (swamp mallow, marsh mallow, fen rose) and salt air (seashore mallow), but also does fine in my sandy soil amended with compost every other year or so. Although late to emerge in spring, once it’s up, it attains full size by July. That’s when the flowers start appearing, becoming prolific as nighttime temperatures begin to moderate in late August. Blooming continues into November most years here in southeastern North Carolina.
Maintenance is a dream: Just cut down – or break off – the hollow woody stalks in late winter. Pest problems are negligible, and I’ve never seen foliage or flowers marred by disease.
Kosteletzkya increases by suckering, which suggests one method of propagation. In my yard, the seed also germinates readily enough in pots of soil inadvertently left around: I imagine a purposeful sowing by someone who actually knows what he’s doing would work as well.
The only problem with Kosteletzkya virginica is its scarcity in the trade. I know from experience it does as well in pot – even accidentally – as it does in the ground. Unpicky about soils, this easy-to-get-along-with plant is easy to propagate, salt tolerant, low maintenance and virtually pest-free. With a native range encompassing nearly the entire East and Gulf Coasts, its selling points include a long bloom season, a self-cleaning nature and a pleasing habit. Is there something you growers know about Kosteletzkya that I don’t?
Fitzgerald’s Gardening, Oak Island, N.C.