Agapanthus 'Galaxy Blue' (Lily of the Nile, African Lily)
Like many people, I sometimes struggle with depression. Often, it is at its greatest depths in the dark days of winter.
I know this time is coming each year and get through it with a variety of resources and techniques. In January, because there are so few days I can work outside, I focus on garden designs for my clients. One of the best things for getting me through January is visualizing their beautiful gardens, fully leafed-out and in bloom the following spring and summer. A good garden has year-round interest. It also has a symphony of color that starts at the tail end of winter and builds to a crescendo in early June, before plateauing into early fall.
Agastache 'Blue Boa' (Giant Hyssup)
I have now been in the garden design business long enough that I’ve built up a portfolio of completed projects. So, as I was contemplating what to write about, I pulled out projects I had designed in January in previous years. I’m not sure why, but it seemed like a good idea to turn to those projects for inspiration. When looking for commonalities, I found that the plant lists I created for clients in January were overwhelmingly dominated by plants with blue blooms. I suppose this should not be surprising, that I designed in shades of blue while listening to sad songs by Bob Dylan and Willie Nelson. But, it got me thinking about blue blooms and about compiling a list of what plants I have the best luck with in creating shades of blue for a garden.
I had a recent conversation with Suzy Askew, a local landscape architect, about the subject of blue flowering plants mentioned in her book, Tennessee Native Plants: A Book of Lists. She wrote, “True blue in the flower world is rare. Himalayan Poppy is always cited as being true blue. Most others are violet to lavender but called blue.”
So, what are some blue flowering plants that do well in Memphis?
First, I love catmint, the various plant species in the Nepeta genus. The leaves produce a wonderful scent and the flowers appear blue enough to me. Like catnip, also in the Nepeta genus, the catmints contain nepetalactone (a substance known to attract cats), albeit not as much of it. Hence, its name.
The most common type of catmint in our area seems to be Nepeta racemosa ‘Walker’s Low.’ Others I like include ‘Six Hills Giant’, ‘Early Bird,’ ‘Purrsian Blue,’ and ‘Blue Wonder.’ One cultivar that I’ve been itching to try, but have not yet gotten a specimen of, is the new dwarf version of “Walker’s Low,” by Monrovia, ‘Junior Walker.’
Hydrangea macrophylla 'Grenikre' (Nikko Repeato Hydrangea)
What I find most attractive in catmint is its versatility. It makes a wonderful long border in a full sun perennial garden, but it can also do okay in part sun, sometimes even in what some would think of as part shade. It can work as a single specimen too. Moreover, because it is incredibly cold hardy, it does very well in outdoor container arrangements.
A similar plant, one that is easy to confuse with catmint, is Russian sage, a plant in the Perovskia genus. Unlike many catmints, it is an exclusively full sun plant. My favorite cultivar, perhaps because I design a lot of small gardens, is Perovskia atriplicifolia ‘Little Spire’. Topping out at only 18-24 inches tall and wide, it really excels in gardens where the scale of everything is tightened.
But, what about blue for shade? Well, there’s always the various cultivars of Hydrangea macrophylla that, when the soil is acidic enough, will produce richly blue blooms. My favorite of these is ‘Nikko Repeato,’ a repeat blooming version of the very common ‘Nikko’ cultivar. (See my February 2019 column on caring for Hydrangea.)
A more unusual, less known choice for blue blooms in shade is the evergreen groundcover and native, Phlox divaricata. I’m especially fond of the cultivar, ‘Blue Moon.’ Commonly known as Blue Moon Woodland Phlox, with a spread of 8-12 inches and a height of 12-18 inches, it can tuck nicely into tight spaces, between roots or rocks, in woodland style under-canopy gardens.
But, if you really want a deep, rich, true blue groundcover, for full sun to part shade, try Ceratostigma plumbaginoides. Commonly known as “Hardy Blue Plumbago” or “Leadwort,” it gets 8-12 inches tall, with a spread of 12-18 inches. When I queried the regionally well-known expert in herbaceous perennials, Jeanne Guidi, owner of Melodia Hill Plant Farm in Jackson, Tennessee, about her favorite blues, this was the very first plant she mentioned. She effusively praised it.
Certostigma plumbaginoides (Hardy Blue Plumbago, a.k.a. Leadwort)
Finally, if you’d like a blue blooming small tree for full sun, perhaps as a nice focal point for a butterfly garden, consider Vitex agnus-castus ‘Shoal Creek.’ Also known as Chaste Tree, it can grow anywhere from 4-15 feet tall and 4-12 feet wide, depending upon how it is pruned. A deciduous tree, many people are planting Vitex instead of crape myrtle, because of the scale insect that has plagued that tree in recent years. I think it makes a particularly nice substitute for the Catawba crape myrtle, Lagerstromia indica ‘Catawba,’ because it is similar in scale and coloring, but without the susceptibility to insect damage.
There are of course, other blue blooming plants that do well in Memphis, including Agapanthus ‘Galaxy Blue,’ Polemonium reptans ‘Stairway to Heaven,’ Agastache ‘Blue Boa,’ Agastache ‘Blue Fortune,’ Scabiosa ‘Butterfly Blue,’ and Mazus reptans, just to name a few.
What are some of your favorite blue blooming plants that do well in Memphis? As always, please feel free to email me at gardener@memphismagazine.com.
John A. Jennings is an experienced garden designer, garden writer, and nursery manager. He also has degrees from both the University of Richmond and the University of Memphis.
