Lily-of-the-Nile (Agapanthus)

* Common name: Lily-of-the-Nile

* Botanical name: Agapanthus africanus

* What it is: Lily-of-the-Nile is a tough, long-blooming, perennial blue flower that’s very common in its native South Africa and warm-weather parts of the U.S., but it’s always been just out of our reach because of too-cold winters.

Several new and recent varieties have been developed that can withstand an average central-Pennsylvania winter, including ‘Galaxy Blue’ (a variety that’s survived for six winters in Michigan trials), Midknight Blue, ‘Blue Yonder,’ and the Headbourne hybrids.

Clusters of blue flowers grow on three-foot-tall stalks above the green, strappy foliage from July into September.

‘Galaxy White’ and ‘Cold Hardy White’ are two of the cold-hardiest white-flowered versions.

* Size: Foliage grows about 2 feet tall with flowers going up another foot.

* Where to use: Try one or two at first in a sunny perennial garden. If they prove hardy for you, lilies-of-the-Nile make a nice summer show massed in clusters or lining sidewalks and driveways. Excellent drainage (think raised beds) is essential for keeping the tender rhizomes from rotting over winter.

Plant in full sun and, ideally, warm-microclimate sites such as along south- or west-facing brick or stone walls.

* Care: No need to dig in winter (a la dahlias and gladioli), but a two-inch layer of mulch is helpful. Cut flower stalks down to the base when flowers finish. Wait until end of winter to remove the frost-killed foliage… the dead foliage helps insulate the plant’s crown (where new foliage emerges) in winter.

Fertilize in early spring with a balanced, granular organic fertilizer.

* Great partner: Blue flowers pair nicely with summer-blooming white-pink panicle hydrangeas (i.e. Pinky Winky, Little Quick Fire, Bobo), which bloom at the same time. Purple coneflowers, liatris, betony ‘Hummelo,’ allium ‘Millenium,’ and pink garden phlox are good perennial partners.