By Jamie J. Gooch
Producing profits through bedding plants, ornamentals & trees. Proving plants can take the heat.
Just like the top auto manufacturers test their cars in extreme conditions to see how much heat they can take, so too do plant breeders. If you want to know how much sun a plant can stand, you have to head South. From the dry heat of Texas to the muggy dog days of Georgia, plant trials separate the stalwarts from the wilters.
Landscapers who want to know how annuals will withstand the heat should explore the trial sites below. If annuals can make it in the southern heat, they’re more likely to perform well this summer in your clients’ landscapes.
Georgia heat
The Trial Gardens at the University of Georgia has been putting cultivars to the test in Athens, GA, for 30 years. It trials plants that come from breeding companies around the world and from perennial plant nurseries, growers and gardeners.
Each cultivar is evaluated semi-monthly for number of flowers; leaf color; uniformity of habit and flower; resistance to insects and diseases; and overall appearance. The regular evaluation is useful for tracking the plant through its lifecycle.
The data is combined into a performance rating, based on a scale of 1-5, with 5 being exceptional and 1 being nearly dead, according to the Trial Gardens at UGA. The performance is graphed over time via updates after each evaluation, which is posted online. That allows landscapers to view performance in real time to see how plants perform over the growing season.
The graphs can be found at http://goo.gl/blpl3.
To make it easy to discover the best performers, the trial gardens name “The Best of the Bunch” for annuals, as well as the best cultivars for each color in each type of annual. They are listed as “Best of the Best” at http://goo.gl/6C6bc.
In addition to its useful online databases, the Trial Gardens at UGA also are open to the public.
Even the sun’s bigger in Texas
The Lone Star State sets itself apart in many ways, not the least of which is by its weather. Summer droughts and extreme temperatures are the norm, which makes growing plants in Texas a challenge. Several trial gardens have taken on the task of finding plants that can thrive in the state’s heat.
The Dallas Arboretum Trial Gardens, for instance, collects weekly data on more than 3,000 entries each year. It then makes that data available via an Excel spreadsheet for download at dallasplanttrials.org. The arboretum also hosts an annual field day for growers, landscapers and breeders.
The arboretum usually gets more than 60 days of 100-degree temperatures annually. It bestows “FlameProof” awards to plants that have been proven to excel in such conditions.
The Dallas Arboretum works with Texas A&M University (TAMU) to help grow and evaluate its Texas Superstar and North Texas Winner’s Circle plants. TAMU also maintains trial gardens at the Texas AgriLife Research Center at Overton, TX.
The Texas Superstar marketing program includes top-performing bedding plants that are well suited to the state’s conditions. The North Texas Winners Circle awards showcase the trials’ top performers each year at flowers.tamu.edu.
States of sunshine
The University of Florida (UF) Fort Lauderdale Research & Education Center Trial Garden site works to provide unbiased evaluations of bedding plant cultivar performance in South Florida via monthly evaluations. The trial garden posts its data and images of each cultivar at http://goo.gl/WeyJx.
UF also has conducted trials in Gainesville, FL: one for the cool season from December to May and one for the warm season from April to August. However, due to budget cuts, trials have been discontinued there. You can still see 2008’s “Best of Trial” winners here: http://goo.gl/x9TgB.
Louisiana also trials color for landscape plantings. It’s known for putting caladiums and other sun garden varieties to the test at the Louisiana State University (LSU) Ag Center in Hammond, LA. And every year, it names the best-performing plants to its Louisiana Super Plants marketing program.
Likewise, the Mississippi Nursery & Landscape Association names plants to its Mississippi Medallion Program every year. The plants are chosen for their ability to thrive in the state, but many of them have excellent heat tolerance characteristics that landscapers may want to investigate at http://goo.gl/ULNgv.
By doing a little bit of homework, you can make sure the plants you install for your clients look great all season long.
Emerald Coast Growers variety focus: Stokesia laevis ‘Divinity’
An exclusive introduction from Emerald Coast Growers, Stokesia laevis ‘Divinity’ features large flowers that open with a coy hint of yellow in the center, then mature to pure, celestial, long-lasting white. Blooms stand serenely over neat mounds of broad, rich green, strap-like leaves. ‘Divinity’ prefers sun to part shade and grows just 12 to 14 inches tall. It is hardy to Zones 5 to 9. ‘Divinity’ is available in 50-plant trays.
Gooch is a freelance writer and editor based in Northeast Ohio.
