Star Gardener: Down the Primrose Path

Tough enough to survive our cold-and-thaw winters and hot, humid summers?
Left, pale yellow, heat-tolerant hybrid primrose. Right, bright yellow Primula Sweet Sunshine Abby Jane Brody Photos

When we think of primulas, or at least when I do, we envision richly colored candelabras growing by streams and other wet places, small gems in the screes and crevices of the high mountains of Europe and China, or even the tender house plants we get to cheer us through the winter.

But tough enough to survive our cold-and-thaw winters and hot, humid summers? Primroses, the common name for primulas, would never come to mind for most of us.

More’s the shame as they can be long-lived, long-flowering, easy and reliable, and colorful, with evergreen rosettes of apple-green foliage. If they have any faults, you could say they are almost too healthy and too generous.  Starting with single pots of small plants, mine grow as large as cabbages, covering broad areas of the garden, with many others given away. 

In this extraordinarily warm winter, the first signs of color turned up in early January. They’ve been in full bloom for the last two months. On mornings after a hard frost or snow, the flower heads would hang, but as soon as the sun rose the heads did, too.

Most, I suspect are hybrids. Wanda, a classic with deep reddish-purple flowers and a yellow eye, may be the most popular of the early primulas. Low and compact, to about three inches high, it blooms over a very long period. I picked up a single small pot at a local garden center. Within a few years after separating the rosettes into individual plants, there were enough for a primrose path. Today they are massed under and around a viburnum.

Dr. Cliff Parks, breeder of the April series of hardy camellias, has also bred a line of heat-tolerant primroses in a broad range of colors, from white and yellow to red, maroon, purple, and blue. Mine have persisted for 20 years.  I’ve tended to choose the softer colors, but am tempted by some of the brighter multi-colored selections. Dr. Parks’s son David, owner of the mail-order Camellia Forest Nursery in North Carolina, carries them. 

The most vivid of the primulas in my garden is P. Dale Henderson, which Dan Hinkley of the former Heronswood Nursery named after the plantswoman who found it growing on an abandoned property on the James River near Williamsburg, Va. It mostresembles the candelabra primroses, with a 10-inch flower stalk sporting a dozen or more clusters of orange flowers with a two-toned bright gold eye. As the flowers age the orange turns to deep rose.

P. Dale Henderson provides a welcome jolt of color just as the weather begins to turn. In a normal year it flowers at the same time as early epimediums and wood anemones; this year the primulas have been flowering since early March, and the epimediums are just opening.

To ramp up the color and turn on the heat at the end of winter, I’ve paired the primula with orange and bronze epimediums and the yellow wood anemone, A. x lipsiensis. Epimedium x warleyense has a bright orange flower, while the versicolor hybrids exhibit a range of bronzes. My favorites are E. x versicolor Versicolor and Cupreum, although any of the versicolor hybrids would work. If you want a softer color pallet, the easy-to-find pale yellow Sulphureum would be a good choice.

It’s possible Glover Perennials might offer Primula Dale Henderson in a few years. In the meantime there might be a few pots when my garden is open for the Garden Conservancy on May 7.

These very early primulas respond well to a rich organic soil with good  drainage. We top dress the beds with compost and chopped oak leaves every winter and have never added fertilizer. They do not require moisture, and I’ve found they tolerate dry periods very well. They perform best in areas with sun in winter and partial shade in summer. Those in deeper shade definitely grow more slowly, but still are robust and colorful.

The plants also want to be divided regularly, which can be a blessing or a burden depending on how energetic or busy you are.

Primula kisoana and P. sieboldii are two other tough and easy woodland primulas that take over later, flowering in May. Unlike the late winter varieties of primroses, these are deciduous, and P. sieboldii goes dormant and disappears after flowering. 

P. kisoana has saturated dark pink flowers and has been described as a “combination of a tart and a thug in one delightful package.” It spreads with underground rhizomes and can make a nice patch. Plants are easy to lift and move to another area and mix well with the many other flowers on the woodland floor in May. “Thug” gives it an undeserved bad rap. There is also a white form.

The Japanese have made more than 500 named selections of Primula sieboldii. The flowers tend to be bicolors, with one color on top and the other on the underside of the petals. It is fairly late to break dormancy, and it’s easy to forget where it’s planted. Just as I’ve given up hope that it is still alive, the first leaves push through. After a dozen years or so in the garden it’s safe to say it is hardy, reliable, and permanent, having made nice colonies. How can you not love a low pink flower named Smooch?

Left, Primula Dale Henderson. Right, Primula Wanda.