Q:
Are there any moisture-tolerant, disease-resistant hybrid shrub roses that you could recommend for my USDA Hardiness Zone 7 garden? I lost two rose bushes that I planted last year and I’m concerned that this site may just get too wet. Before it was developed for housing, my yard was apparently a wet woodland. It slopes slightly and seems to hold moisture after any precipitation.
Art Zimmerman, Newark, DE
Rosa palustris and R. foliolosa, two species roses that are adapted to wet soil, both have single pink flowers. For best results, purchase ones that are growing on their own roots.
Photo/Illustration: Jennifer Blume
A:
Andrew Schulman, owner of Country Lane Gardens, a nursery that specializes in old roses, replies: Most roses will not tolerate standing water or soil that stays saturated for more than a few days at a time during the growing season. If your garden floods regularly after rains, it’s likely the roses you planted did indeed “drown.” Replacements will suffer the same fate unless you are able to improve the drainage.
To check for adequate drainage, choose a spring day when it’s not raining and dig a 2-foot-deep planting hole, as you would for a new rose plant. Observe the hole over the course of a few hours. If the hole fills with water, chances are the soil drains too poorly to support roses. If the hole remains dry, fill it with water. If the water does not drain away after several hours, it’s likely that roses will fail there unless you improve the drainage. If the hole drains, but only slowly, you could experiment and try planting some carefully selected shrub roses.
I know of only two species that are adapted to wet soil: Rosa palustris (sometimes called the swamp rose) and R. foliolosa. Neither has been used extensively by hybridizers. R. palustris is native to your area, and may even have grown in the damp woods that your neighborhood was built over. It is a tough, disease-resistant rose bearing single pink flowers during midsummer. R. palustris might be a good match for your site.
R. foliolosa is a short-growing, thornless rose that tends to sucker into a low thicket. It bears charmingly crumpled, single, deep-pink flowers over a long summer season. There is an outstanding hybrid of R. foliolosa called ‘Basye’s Purple Rose’. It’s a tall, thorny shrub with dark branches and exquisite, wine-purple, single flowers. Its other parent is the drought-tolerant R. rugosa. Although its tolerance for wet feet is untested, it’s especially healthy and vigorous. It might be worth experimenting with on a damp site.
If you plan to try any of these roses in a damp area, buy plants growing on their own roots. Bud-grafted roses will come on standard rootstocks that are not adapted to poor drainage.