Like most people, I love the color blue. Compared to white, pink, red and yellow, not a lot of blue flowers are out there. And even some plants with blue in their name are more lavender or violet.
That brings us to a fine perennial called leadwort. I write about this plant every few years because it seems to remain obscure, even though it is sold in many garden centers.
The botanical name, Ceratostigma plumbaginoides, is a mouthful, hard to say and hard to spell. But the common name leadwort is pretty easy to remember.
The flowers are its reason for being. They are small and round and the most beautiful color of cobalt blue. This is a real blue – not violet, not purple, but real blue – and it’s like a beautiful jewel.
A second asset is its season of bloom. While a few buds open earlier, late summer into autumn is its flowering season, atop the robust growth that filled out since the plant broke dormancy late in the spring.
The plants stay small, about 12 inches high with a low, mounding effect. That makes them good edgers for a flower bed, perhaps as a companion for candytuft or creeping phlox, which bloom earlier and are green by midsummer. A background of bright yellow or orange summer flowers can make an especially bright scene of contrasting colors.
Leadwort’s foliage is semi-evergreen, meaning it loses a lot of foliage in the winter. However, slender stems remain above ground, which helps to remind you it is there when you are looking for space to set out new plants. It sometimes takes awhile to wake up in the spring, so don’t give up early on leadwort. It will eventually break dormancy and grow new leaves.
Set out plants 10 to 12 inches apart in sun in good soil improved with compost. This also helps soil drainage, which is important. I have had no luck in the shade with leadwort. It expands by underground stems called rhizomes, so a nice, low clump can form from two or three plants. It is a long-lived perennial.
While the most bloom shows up in late summer, some blooms will linger into autumn, when the foliage takes on a bronze-to-reddish hue that is very attractive among the fall colors.
If you are attracted to this plant on the shelves in garden centers, don’t hesitate to buy and plant it now. But pay close attention to watering it for the rest of the summer.