Many factors in a greenhouse can contribute to the spread of disease. The warm temperatures and humid conditions make the ideal environment for diseases to thrive. Depending on the type of irrigation used, the foliage of plants may be wet for extended periods of time, which also contributes to disease development. Growers often space plants in close proximity to efficiently use their square footage, but this can also decrease airflow between plants and spread disease faster.
Inspired by the lively, foot-stomping music of Southwest Louisiana, this zinnia bursts with sunshine-bright, fully double flowers that are noticeably larger
This member of the Sunjoy series of barberry is disease resistant and sterile, making it the responsible choice for this popular landscaping plant. Proven Winners ColorChoice Sunjoy Mini Maroon barberry has a semi-dwarf, mounded 2- to 3-foot habit with purple-burgundy foliage (USDA Zones 4-8).
This is a truly game-changing plant – the first Italian sweet basil that’s resistant to downy mildew, a disease that commonly plagues basil plants. Unlike typical basil, Amazel is seed-sterile, so it continues to produce leaves and shoots even after flower initiation.
Scabiosa‘Vivid Violet’ boasts large, violet pincushion flowers atop low mounds of frilly, mildew-resistant foliage. This vibrant variety is especially resistant to powdery mildew.
Rudbeckia‘American Gold Rush’, with its domed clusters of short orange coneflowers, is ideal for mass planting or as a perennial border. The plant’s thin, hairy leaves contribute to its resistance to septoria leaf spot and other diseases
The flagship variety of the Luminary Collection and the gold standard of powdery mildew resistance. In an extensive mildew trial, this was the very best variety to display resistance.
NewGen Freedom is a true workhorse in the landscape. Its vigor helps create an attractive plant faster than most traditional cultivars. Multiple years of trials confirm good boxwood blight resistance with proper care and good resistance to boxwood leafminer.
Monardas are often grown too close together becoming crowded in the garden which reduces air circulation or kept too dry, causing greater susceptibility to foliar diseases such as powdery mildew. ‘Midnight Oil’ stays clean and is a useful plant in the garden, lending striking contrasting color and powdery mildew resistance.
This compact variety is great for gardens of all sizes. Native to North America, its stunning flowers are a host for beneficial pollinators. Burgundy fall foliage extends the garden season and is leaf spot resistant.
Thanks to expert breeding and years of trials, this collection of fragrant shrub roses has the same hardiness and disease resistance of multiple award-winning Flower Carpet groundcover roses. Flower Carpet Fragrant shrub roses are large-bloomed and beautifully fragrant with a glorious old-world look, but with all the benefits of modern disease resistance.
Just like all Garvinea varieties, ‘Sweet Maggie’ is highly resistant to pests, diseasesand various weather conditions. From rain and storm to the sunnydays: remove the old flowers and ‘Sweet Maggie’ will perform from early spring to the first frost.
‘Huggy Bear’ features the typical pink-violet geranium flowers in spring, but stuns with its large, chocolate-red foliage. It is more disease-resistant and sun-tolerant than others in this adaptable North American native species.
The combination of prolific dark rosy blooms and dark purple leaves make Shadow Magic Crapemyrtle a standout in any warm-climate landscape. While many dark-leaf crapemyrtle are riddled with foliar issues, Shadow Magic is incredibly disease resistant, especially to powdery mildew.
New for 2025, Solanna Sunset Bright features sunny golden flowers with a red ring and enhanced tolerance to powdery mildew.
All varieties in the Ditto family contain White Rust Resistance (WRR), powered by Intrinsa. The long flowering window makes the Ditto family a hit for retailers and consumers.
‘Everillo’ sports lime green foliage that progresses to a bright, golden yellow. Sun exposure intensifies the yellow, while shade pushes foliage toward chartreuse. Adds a burst of color to mixed containers, garden beds, and borders, especially in winter months.
The debut Better Boxwood collection’s new cultivars represent the first scientifically bred blight-resistant boxwood. ‘Renaissance’ is the collection’s conveniently compact, low-growing variety that’s perfectly suited to small globes, low hedges, parterre and knot gardens, and container plantings.
Due to the ease with which disease can spread in a greenhouse, breeders are more focused than ever on developing varieties that are disease-resistant. Many new varieties have disease-resistance bred into the genetics, and breeders acknowledge that this is one of their goals with new products. Check out the slideshow for a closer look at some new disease-resistant varieties (you can also find more varieties here).
Teresa Hendrix is a writer for Onyx Express, covering all of the news, arts, construction, automotive, travel and real estate. She also writes about fashion and her other interests.
