Ask Mr. Sage: Why Didn't My Fall Blooming Salvia Flower?
Dear Mr. Sage,
Please forgive me, but I am so frustrated! I know that you list Limelight Mexican Sage as being perennial in Zone 7, so I expected that it would grow more than pretty foliage for me in my Roanoke, Virginia, garden when I planted it in spring 2020. But what a dud! It never even bloomed before first frost arrived in mid-September. What can I do to help it bloom next year?
Nipped in the Bud
Most likely you are doing all you can to give this plant good growing conditions by providing loamy soil, plentiful water, and a sunny to partially shady setting in an area that is right for it according to the USDA Plant Hardiness Zone map. However, September is too early to expect any Salvia Mexicana (Mexican Sage) to flower.
Every plant has its own growth schedule and capabilities. True, Salvia mexicana ‘Limelight’ is cold hardy, and therefore perennial, in your area. However, being perennial in Zone 7 only means that, once established, a plant's roots usually can survive a winter low of 0 degrees F to grow again the following spring. It doesn’t indicate an ability to flower after frost.
By the way, to get established, a plant usually needs significant time in ground before frost — perhaps two months — for roots to spread, get anchored, and withstand winter chill. So, your Limelight Mexican Sage should come back next spring. Whether it blooms before Roanoke’s first frost in 2021 is another matter.
If grown in a warm enough winter climate, all types of Salvia mexicana bloom from fall through winter or until frost strikes. However, the day you consider to be the beginning of fall depends on whether you accept the astronomical seasons model based on the fall equinox (roughly September 22) or the northern meteorological model (September 1).
At FBTS, we use the astronomical model. When we say that a plant is an autumn-to-winter bloomer, we mean that it likely will begin flowering sometime after September 22. In places where first frost regularly occurs either before or shortly after the equinox, gardeners are likely to be disappointed by fall-to-winter bloomers.
First frost came surprisingly early in Roanoke this year. But maybe you’ll be luckier with Limelight Mexican Sage next season, because the National Weather Service says that first frost can arrive as late as mid-November in your area. Also, it’s our experience that the onset of flowering for perennials is late during their first season. In following growing seasons, they seem to begin flowering a bit earlier due to better establishment of roots and greater mass.
When purchasing plants from any nursery, it’s essential to consider the your local hardiness zone and the length of its growing season as well as first and last frost dates. To avoid the frustration of short autumn bloom, consider choosing plants that begin flowering in summer.
For the sake of clarity, I need to note that the common name “Mexican Sage” confuses lots of people who think it refers to any number of Salvias native to Mexico. Also, don’t confuse it with “Mexican Bush Sage,” which refers to Salvia leucantha. Both S. Mexicana and S. leucantha are popular in the South and in moderate coastal climates. However, S. leucantha blooms summer to fall and may be a better choice for long bloom in your Southeastern garden.
Each plant description in our Flowers by the Sea online catalog includes a cultural icons tab leading to a quick visual summary about the plant, such as its needs, size at maturity, hardiness, and seasons of bloom. But if you need more information, please feel free to contact us. We’re always glad to share information about the many plants we grow.
Thanks for your question,