Not all botanical garden plants are up to the rigors of life in Missouri's gardens. Growing conditions vary widely across Missouri. Saint Louisans carve their gardens from heavy clay. Those in the state's heartland and Bootheel rejoice in the Mississippi and Missouri rivers' rich alluvial deposits. Spring's frequent thunderstorms, summer's intense heat and humidity, and winter's frigid temperatures add to the difficulties.
Apple Serviceberry 'Autumn Brilliance'
The Missouri Botanical garden selected the apple serviceberry (Amelanchier grandiflora) cultivar as a 1999 Plant of Merit for its overall performance throughout Missouri and southern Illinois. "Autumn Brilliance" is a 15-to-25-foot high and wide shrub or tree hardy to winter temperatures of minus 30 degrees F. Before their leaves emerge in April, its branches bear fragrant dropping clusters of five-petaled white blooms. Blue-green leaves up to 5 inches long become brilliant red-orange in autumn. Edible summer berries follow the flowers, maturing from pale green to red to deep purple. They make tasty preserves and pies.
Plant disease-and-pest-resistant apple serviceberry in shrub borders or as an ornamental tree against a dark backdrop that will accentuate its autumn colors, advises the Missouri Botanical Garden. It likes full sun to part shade and average, well-drained soil.
Globe Amaranth 'Buddy'
The globe amaranth (Gomphrena globosa) "Buddy" cultivar is a 2001 Plant of Merit. A long-blooming annual, it stands 1 to 2 feet tall and up to 1 foot wide. Its true flowers are small white or yellow funnel shaped blooms invisible from a distance. The bracts enclosing "Buddy's" blooms are vivid purple, papery globes reminiscent of clover blossoms. They provide garden color from June until frost. The bracts are effective in both fresh and dried floral arrangements. Plant "Buddy" in a sunny, well-drained location. Water regularly during dry periods. Stake taller plants if necessary.
Mexican Petunia 'Purple Showers'
Mexican petunia (Ruellia brittoniana) "Purple Showers," a 2009 Plant of Merit, is evergreen in warm winter climates. In Missouri, however, it grows as a clumping annual. Standing 3 to 4 feet high and 2 to 3 feet wide, it has deep green sword-shaped leaves. Deep purple petunia-like blooms top its greenish-purple stems from late spring until frost. Profuse flower production compensates for each flower's 24-hour lifespan. Missouri's hot, humid summers don't affect disease-and pest-resistant "Purple Showers." It tolerates a wide range of soils, says the Missouri Botanical Garden, but does best in moist to wet soil and full sun.