When planning the vegetable garden, many of us look for disease-resistant varieties to avoid blight, mildew, and bacterial infections. But what about your flowers? It’s no fun when your phlox or Monarda have powdery mildew, or your roses succumb to blackspot. The good news is that you can look for varieties that offer disease resistance for these common issues. Here are a few examples.

Disease Resistant Annuals and Perennials in the Landscape

Powdery Mildew on Phlox

Big, luscious phlox flowers are an old-fashioned favorite, but they are notorious for succumbing to powdery mildew, a fungal disease. Even though it is not fatal to the plants, it doesn’t look good.

Creeping phlox is a hardy, vibrant variety that is immune to powdery mildew and a lovely addition to the garden, particularly for those wanting early-season color. For the tall varieties, look for ‘Blue Lagoon,’ ‘Hot September Pink,’ and ‘Cinderella,’ just to name a few to minimize the mildew issue.

Rosemary and Powdery Mildew

Bee Balm and Powdery Mildew

Another one of my favorite summer flowers is Monarda, also called bee balm because it is a powerful pollinator attractant. However, it frequently contracts powdery mildew. ‘Jacob Cline is the classic bright red flower with good resistance to powdery mildew, and ‘Pardon My Pink’ bee balm is another option in a hot pink hue.

Disease Resistance for Roses

As beautiful as roses are, they can also be a magnet for various pests and pathogens, with black spot, another fungal infection, as one of the most prominent. In addition to cultural considerations such as not watering overhead and planting to provide optimum air flow, look into disease-resistant options. ‘Knock Out is a shrub rose with deep raspberry-colored flowers that resists blackspot in a wide range of conditions. Plus, it is renowned as an excellent specimen that blooms throughout the season.

Another almost fail-safe option is the Canadian Explorer series, which has a deserved reputation for being super hardy and holding up against blackspot and powdery mildew.

Combatting Diseases of Asters

Asters are another large genus of flowers known for a wide range of foliar diseases, such as powdery mildew and rust. Powdery mildew is another fungal disease readily identified by the orange-red spots on the undersides of the plants’ leaves.

The lavender-colored  ‘Doktor Otto Petschek,’ violet ‘Jungfrau,’ and violet-blue  ‘Jindai’ all have excellent resistance to both fungal infections.

Keeping Verbena Healthy

Brightly colored verbenas make a statement in annual plantings and pots, but they can succumb to diseases such as Botrytis rot and other fungal diseases, such as powdery mildew. The ‘Aztec’ series, including Aztec Deep Coral Red and ‘Superbena’ from Proven Winners, is known for its solid overall disease resistance.

The level of disease issues a gardener has often depends upon their location, with many thriving in warm, humid environments. Of course, this does not preclude other areas from having problems, which is why it’s good to know what flowers have built-in resistance to some of these most common disease problems.