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Annual Flowers from the King’s Garden: Blue Salvias

Dr. Leonard Perry, Horticulturist in Residence

SalviasOne of the annual flowers that Marian Kruger Coffin used in her 1920 design of the King’s Garden was salvia or flowering sage.  Of the over 900 herbaceous species of salvias worldwide, she used a couple—the mealycup sage (Salvia farinacea) and the azure or blue sage (Salvia azurea), sometimes seen too as pitcher sage.  Both are great garden annuals, still found in commerce today, and both provide blue flowers unlike the salvias known to most gardeners.  These will tolerate part shade, but prefer full sun for best bloom.

Although blue sage is typically grown as an annual flower, it is listed as hardy into southern Minnesota and warmer parts of our region (USDA zone 5, or minimum average winter temperature of -10 to -20 Fahrenheit).  It is native to the central and southern states, often found in prairies on somewhat dry soils.  The flowers in late summer into fall attract bees and butterflies seeking their nectar.  Growing three feet or more high, interplant them closely (one foot or so apart) with other annuals or grasses to keep these salvias from flopping over.  Cutting plants back by half in late spring will make them more bushy and less prone to flopping.  Otherwise, it is an easy-to-grow flower.

Mealycup sage is so named for the “mealy” or felty hairs on the flowering stems and outer parts (calyces) of the flowers.  It is grown as an annual flower in northern gardens, as a tender perennial elsewhere, and only as a perennial in warmer climates such as its native Texas and Mexico.  The flower spikes are one and one-half to three feet high, on square and branching stems (the square stems are a clue it is in the mint family).  The blue flowers cover the top four to eight inches of these stems, from early summer into fall.  They have an upper hood over a lower tip.  Cutting flower stalks off after bloom will promote new flowering stems sooner.

mealycup sage butterfly salviasMealycup sage is showy in mass on their own, or mixed into borders and containers to add a vertical accent and the less common blue color—a great contrast to most other colors.  They’re attractive to butterflies and hummingbirds. Use them also as a cut or dried flower.  Mealycup sage is easy to grow, too, having few problems, usually resistant to deer and rabbits, and tolerant of poor soils and some drought.  Plant these upright annuals one foot or less apart.

While Marian Coffin only specified the species of the mealycup sage, and it is still available, there are several cultivars (cultivated varieties) you may find.  Two of these—Blue Bedder and Rhea—are planned for the King’s Garden in 2016.  Blue Bedder salvia has darker violet blue flowers than the species, while Rhea (shown in the photo) has similar dark flowers but is more compact—only about one foot or so high.

Victoria is perhaps the most popular mealycup sage cultivar, with similar flowers to Rhea only perhaps not quite as dark, and on larger plants with indigo blue stems. It has been around a while, winning the Fleuroselect award in 1978.  As good or even better in some locations and years than Victoria, taller with more stems, is the similar older German cultivar Gruppenblau (“group blue”, from Johnny’s Seeds).  Evolution also is compact with good branching and deep violet-purple flowers, and won top awards in both the European Fleuroselect (2002) and All-America Selections (2006) flower trial programs.

Strata is an older cultivar, similar in height to Victoria (18 inches or so high), only with clear blue and white (outer calyx) flowers.  It also won a Fleuroselect award (1996). Similar in height, only with sapphire blue flowers is the Fleuroselect winner (2008) Fairy Queen.  White spots on the flowers resemble fairy dust.  Argent is an older  cultivar with all white flowers, and is less commonly found now.  A newer selection with stems in dark blue, sky blue, and white is Cathedral Blue.

Indigo Spires resembles Victoria only is taller (three feet or more in hot climates), and has richer deep blue flowers.  It is a hybrid of mealycup sage supposedly with a Mexican native salvia (longispicata), found in 1979 at the Huntington Botanical Garden in San Marino, California. The patented Mystic Spires is another similar hybrid, only shorter.

Look for some of these blue mealycup salvias in your favorite garden retailer this spring, as well as the first two in the King’s Garden this summer.  If you’re ordering seeds to start your own (which is a good way to ensure you’ll have them), plan on sowing seeds indoors about 8 to 10 weeks before planting outside after the last frost.