Lithodora 'Blue Star'

Lithodora diffusa
Blue Star

When planning a garden, there’s nothing wrong with playing it safe. In eastern Massachusetts, rudbeckia is a guaranteed long bloomer and geranium ‘Rozanne’, with its prolific, long-lasting dark blue flowers, has proven why it was perennial plant of the year in 2008. Both have a place in anyone’s planting scheme.

But every gardener also needs to step out on the edge if his or her hard work is going to attract second looks. Perhaps it’s a plant that pushes a zone or a shrub that prefers shade placed where it will get half-day sun. The reward for taking chances is achieving the unexpected.


In the Bressingham Garden last spring and summer, visitors gathered to take a closer look at a small clutch of low-growing, mounding perennials that produced a stunning flower. The small, five-lobed blooms were white with a pale blue stripe converging on a darker blue center. The blooms were all the more stunning because they were set against very dark green foliage. The delicacy of the flowers made the accents appear almost hand-painted.

The perennial that stopped everyone in their tracks was Lithodora ‘Blue Star’. It grows to an eight-inch mound and blooms from May into summer.

It also has no business being in a garden in suburban Boston. ‘Blue Star’ was developed in Fresno, California, by Takao Nurseries, and it’s considered marginally hardy in Zone 6. Lithodora, in turn, came to America via southern Europe. Translation: a hard winter could kill it hereabouts.

Elm Bank has just come through a cold, wet winter, with an emphasis on the ‘wet’. And, in this case, the snow cover lasted from December to early April. There was no January thaw, and that’s likely the reason why ‘Blue Star’ has come back looking vigorous and ready for another season of making visitors reach for their cameras.

Hardiness zones are an ambiguous guide. They should be taken as a suggestion rather than a stone tablet handed down from the USDA. Anyone who has had an annual growing next to their foundation surprise them by reappearing the next year knows that protection can make all the difference to a plant’s success. A thick layer of mulch, branches, or snow can protect against the freeze-thaw cycle that kills many perennials.

Ideally, a perennial should go dormant in winter and stay that way until spring’s warmth brings it back to life. The enduring blanket of snow kept ‘Blue Star’ properly dormant through the winter and early spring.

In the Bressingham Garden, the mounded beds sculpted from the one-time tennis court provide much the same function as a raised-bed planter in a garden: everything warms up a little sooner in the spring. Now, the gentle mounds of the garden are helping to nudge this crowd-pleaser back to life in the spotlight.

On April 17, the prognosis for ‘Blue Star’ was quite favorable. There’s a little winter kill (to be expected) but the three mounds that comprise the perennial appear vigorous and ready to expand. Get your cameras ready.