This field of purple coneflowers isjust one of the top 10perennials of this year.

By now, you're hooked. Your garden is increasingly a perennial one. Your yearly investment in annuals gets smaller and smaller, and every year more and more of your plantings return in the spring. Who was it who said, "Friends don't let friends plant annuals"? Well, that may be a tad harsh. Because many perennials have shortcomings, especially in the frustratingly short length of bloom time. Most annuals bloom all season long, but your standard perennials -- what, four weeks?

Gardeners can have flowering perennials in their yard all season though, as long as they plant a select group of easy-to-grow, long-blooming perennials. A worthy trade group called the Perennial Plant Association has a yearly "plant of the year" award simply to let gardeners in on this trade secret. The group has picked a perennial annually for 13 years now, beginning with the ground cover Plox stolonifera back in 1990. Here we list the 10 perennial plants of the year -- a decade of all-stars, chart-topping charmers all, a veritable Top 10 of the horticultural world.

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Blue Speedwell

Veronica Sunny Border Blue The 7-inch, dark blue spikes of this veronica bob atop a plant that grows low enough that you can actually place it at the front of the border. And when was the last time you saw something this vertical placed way up front?

Bloom Time: Early summer to late autumn. Height: 18 to 24 inches. Hardiness: To 40 degrees F below zero. Light: Full sun to very light shade.

Purple Coneflower

Echinacea purpurea Magnus This prairie wildflower achieves a level of sophistication in the Magnus variety, which throws its petals out horizontally daisy-style, instead of thrusting them downward like a tattered slip. A great cut flower.

Bloom time: Midsummer to early autumn. Height: 2-1/2 to 3 feet. Hardiness: To 40 degrees F below zero. Light: Sun.

Black-Eyed Susan

Rudbeckia fulgida Goldsturm Here's another prairie wildflower that often gets a bad rap because of its overuse. Common, you say? Well, of course! Goldsturm, despite its Czech and German origins, is truly an American icon. And it's an endearing pass-along plant. Plant three and soon you will have seven. Then it's time to share.

Bloom Time: Midsummer to late fall. Hardiness: To 30 degrees F below zero. Light: Sun. Height: 2 to 2-1/2 feet.

Purple-Leaved Beard-Tongue

Penstemon digitalis Husker Red These pink-tinged white flowers and the maroon-red foliage are quite a display in and of themselves. But, really, they pair nicely with almost anything. As with all purple foliage, a backdrop of lighter color foils that "black hole" syndrome.

Bloom Time: Early to late summer. Height: 2-1/2 feet. Hardiness: To 40 degrees F below zero. Light: Sun.

Pink Astilbe

Astilbe Sprite These feathery plumes top fernlike foliage, a wondrously dainty combination. The leaves often take on a bronze cast, making this plant all the more interesting. An aside: kind of thirsty.

Bloom Time: Midsummer to early fall. Height: 18 to 20 inches. Hardiness: To 30 degrees F below zero. Light: Partial sun to full shade.

Blue Pincushion Flower

Scabiosa columbaria Butterfly Blue While this plant does seem to flower forever, it looks kind of lost all by itself, giving you the perfect opportunity to pair it with Coreopsis Moonbeam. The blue-yellow combo is classic.

Bloom Time: Midsummer to early fall. Height: 12 to 14 inches. Hardiness: To 30 degrees F below zero. Light: Full sun to very light shade.

Blue Perennial Sage

Salvia superba May Night Not to be confused with your herb garden sage, May Night is both cold hardy and showy. The blue-black flower is lustrous and darkly sinister at the same time. Site this so that the coloration does not recede in the distance.

Bloom Time: Midsummer to fall. Height: 22 to 28 inches. Hardiness: To 25 degrees F below zero. Light: Full sun.

Purple Coralbells

Heuchera micrantha Palace Purple Here's a plant with a multitude of virtues. Chief among them is the crinkly multicolored foliage. Really spectacular, especially up front and en masse. The tiny, tiny flowers have their fans, but those folks probably carry power lenses. This plant can really stand up to abuse, too.

Bloom Time: All summer long. Height: 12 to 14 inches. Hardiness: To 30 degrees F below zero. Light: Partial sun to partial shade.

Threadleaf Tickseed

Coreopsis verticillata Moonbeam Maybe Moonbeam coreopsis is not the most impressive weapon in a gardener's quiver, but its soft yellow color and ferny foliage complement absolutely everything.

Bloom Time: Early summer to fall. Height: 16 to 18 inches. Hardiness: To 35 degrees F below zero. Light: Full sun to very light shade.

Russian Sage

Perovskia atriplicifolia This large-scale perennial can tower over garden beds in much the same manner as some of the more imposing ornamental grasses. But Russian sage combines colored foliage with honest-to-goodness flowers.

Bloom Time: Midsummer to fall. Height: 3-1/2 to 4 feet. Hardiness: To 30 degrees F below zero. Light: Full sun.