A Half-dozen Great Garden Perennials

By for CAES News

We are inundated with new perennials today. Perhaps too many, if you're like me and can't resist taking every blooming thing home every time you visit your garden center.

However, a few plants over the past few years have proved top performers in Georgia gardens. Here are six of my favorites. All have passed through the University of Georgia evaluation program.

These are the essential plants for any garden. I chose them for their vigorous growth, garden center appeal and unusually good landscape performance over a range of soils.

You may have to search for the cultivars, but they're all in the market in Georgia.

Kniphofia uvaria 'Shining Scepter'

Once torch lilies are established, they become true survivors. They're in the "must have" section of any perennial list.

Select a full-sun border spot with good drainage. The striking plants show up splendidly against a dark green background.

From torch lilies' sometimes bewildering flower variability comes superior selections. And "Shining Scepter" is one of the best, with its intensely golden 3-foot-tall spikes.

Shining Scepter blooms just two to three weeks in late spring to early summer. Unlike other torch lilies, it's a bright, bold yellow that blends into a peachy-orange color. It reminds me of those orange-and-vanilla-ice-cream popsicles I loved as a kid.

This is a true bedding perennial. In groups of 20 to 30 on 8-inch to 10-inch centers, it generates an incredible display.

Despite its cast-iron physiology, it requires good fertility to produce the best flowers. Fertilize in early spring and again in midsummer after you remove the bloom spikes.

Rosmarinus officinalis 'Athens Blue Spires'

I thought all rosemary pretty much looked alike, grew alike and tasted just fine on roast chicken. Then came "Athens Blue Spires," a solitary rosemary planted next to the campus greenhouse doors.

It grew vigorously. It bloomed profusely. It smelled heavenly in the late-morning sun. And yes, it tasted great on chicken.

After five years, through drought and cold, no one could ignore its incredible mid-spring spread of powder-blue flowers against deep green leaves.

A mature specimen (ours) stands 5 feet tall and equally wide. We don't fully know how cold-hardy it is. It's likely hardy in Zone 6. Even treated as an annual or a patio plant to be brought in, its vigor and flowering habit make it a wonderful kitchen herb.

Like all rosemary, it requires bright sun, well-drained soils and a relatively high organic content to grow its best. Once established, it needs no than a light spring fertilizing.

Phlox paniculata 'Robert Poore'

Phlox are my favorite perennials. They produce long periods of blooms, attract butterflies and hummingbirds, are easy to grow and propagate and can withstand 100-degree summers and 25-below-zero winters.

Robert Poore is the perennial my neighbors most commonly request. It contains all the necessary traits of a good phlox: strong stems, large floral display over eight weeks in Georgia and relative freedom from disease.

The color is a clean, rosy purple that seems to glow when planted next to the common "Lavender" hand-me-down phlox.

This phlox is slowly making its way into mass production. It makes an incredible mass display. You can get away with mass-planting because it has good mildew resistance.

Gardeners will cherish the new, mildew-resistant phlox varieties and new colors now available, including some of the finest flower colors and diversity ever seen in the genus. I can't wait for spring.

Coreopsis grandiflora 'Flying Saucers'

"Flying Saucers" has large, bright-yellow flowers that catch your attention. The foliage is a dense cluster of rosettes that forms a wonderful, clump-like display in the pot. It looks like gangbusters in a fall-established, 1-gallon container.

As a genus, coreopsis is a highly praised garden perennial. On wiry stems well above the lance-shaped leaves, its yellow, daisy-like flowers nod gracefully in light breezes from late May through July.

Deadheading (removing spent flowers) prolongs the flowering. Plants grow up to 3 feet tall, depending on the species or variety. Plant coreopsis in full sun in a well-drained site. Water during periods of sparse rainfall.

All coreopsis perform well in the landscape. They're fantastic in groups of 50. Some seem to expire in two or three years. This is reportedly not the case for Flying Saucers. But the test of time is ongoing. My specimens are in their second year.

Cuphea micropetalum (The Great Cuphea)

I've never grown a bad Cuphea. "Lavender Lady," "Georgia Scarlet" and many other prostrate forms grace my rock gardens and borders.

Cuphea micropetalum is something else altogether. It's big, showy and great for hummers and butterflies. The 3-foot-tall plants grow fairly fast and seem to thrive in the heat.

The cigar-shaped trumpet flowers are best from midsummer to frost. They're prone to seemingly random expressions of bright yellow, orange and deep red.

From 20 feet or more you see a pleasant display. But the real pleasure comes from sitting next to this plant on a patio or deck. I find myself staring, just taking in the high-contrast colors.

Full sun, good fertility, drainage and regular watering is the rule in Georgia. It will likely not require watering in more moderate climates. Young plants benefit from pinching.

It's easy to grow and relatively pest-free, unless you consider tiger swallowtail butterflies pests.

Pentas lanceolata 'Nova'

NovaBy now it's no secret I'm a butterfly/hummingbird gardening zealot. Having grown this pentas selection for seven years now, I would never plant a butterfly garden without Pentas Nova.

This plant has no downside.

Larger and much more vigorous than most pentas, it sports truly beautiful lavender-rose flower clusters that are irresistible to hummingbirds, butterflies, bee moths, sphinx moths and other colorful garden animations.

Nova is a full-sun annual that benefits from early pinching and occasional deadheading and shaping. A meticulous gardener can generate an incredibly dense plant by midsummer.

But left to its own devices, it's still a good performer. It grows best when soil temperatures are warm, so northern-climate gardeners may want to plant this treasure in June.

I have yet to have a midsummer garden visitor who didn't exclaim, "What is that thing? I want cuttings!"

Pentas Nova is now a Georgia Gold Medal Plant Selections Winner.

Paul Thomas is a horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.