Platycodon (Balloon Flower). Upright, clumping habit: 24-36' tall... mine tend to be on the taller end. Doesn't like to be disturbed once established, but self seeds without going crazy. Last thing to break ground in the spring, so it's always a good idea to mark their spot in the fall. I only have the Fuji Blue and lots of it because it seems to go with everything, but there is also Fuji Pink and Fuji White as well as a dwarf variety -"Sentimental Blue".

The following plants all tie for number one with me. (Sorry :)
Achillea Coronation Gold (2 feet):great foliage, beautiful blooms and long blooming time
daylilies: Beautiful Edgings is my favorite yellow:this one reblooms most of the summer
Cannas (particularly colored foliages like purple leaved Wyoming and Green/yellow striped Phaison)
Rozanne Geranium (12 to 18 inches. Fabulous for the front of the border) It just blooms its head off all summer.
Salvias (Mystic Spires (2-3'), Black & Blue (2-3'),and Victoria (12-18 inches)

I cant pick just one either! Too hard : ) Top 5:

Liatris
Moonbeam Coreopsis
daylilies
Blue Baptisia
Autumn Joy Sedum

Jen

My absolute favorite is Magic Fountain Delphiniums.
THe larger ones, that I hold up with tomatote stakes.
Blooms all summer, the foilage is awesome an the flowers are incredible.
I have never seen a truley blue incondenscent flower like this in my life.
I have 3. They are still budding. They love rose food and plantly of water and FULL sun.
They also come in a beautiful dark blue that I will check out at the nursery next spring.
This is what I have now.

Here is a link that might be useful: Delphiniums

My favorites:

Peonies
Phlox Paniculata 'Franz Schubert', 'David' and 'Nora Leigh' are at the top of my list.
Platycodon (Komachi is my favorite, the "balloons" stay closed, instead of the traditional star shape blossom.)
Shasta Daisy 'Alaska'
Persicaria polymorpha, (a very large and vigorous plant)

Lime Light Hydrangea tall 4ft...great flowers to dry.
Any of the Phlox.
Shasta Daisy "Bright Lights"
Grasses mostly varigated.
All Sedums in my Rock Garden especially varigated & dark ones.
Rudbeckia's set off the fall theme.
Turtles head...stands 3ft sturdy plant with great leaf texture and flowers.

Redsox - it's too hard to pick just one!

Phlox paniculata, maculata, and carolina - I love all the border phloxes!
Monarda didyma and fistulosa
Echinacea purpurea
Irises

Gee, I could go on and I'm sure there are lots more I haven't even discovered yet...:)

I love my false sunflowers best (heliopsis - I dont know the variety).
They are about 5 feet tall - shorter if cut back by half in June.
Last year my first year plants were covered with 3-4 inch daisy like flowers from the end of July until frost. There are pros and cons to the following for me: They are big re-seeders, they attract a lot of bees.
I have to join the moonbeam bandwagon too - it is my easiest plant and it just always looks great.
I also love my Russion Stonecrop ground cover. I dont know the latin name - it was here when I moved in. It helps prevent weeds, looks great all summer and has pretty yellow flowers in the spring.

So far, I do have one Magic Fountain Delph and one other Delph. They repeated but in August started to look really shlocky so I don't know if they will come back next year. Like someone pointed out in an old post, if you love the Dephs, they are only aboutr $9 at Lowe's so they become an annual instead.

I also have the hydrangea Limelight, which we inherited with our house. Does anyone know when to prune it (just for shaping)?

The hydrangeas that bloom on new wood should be prunned in the spring. Shape it when you see new growth (early) then let it go. They are the easiest hydrangea. Also a Pee Gee hydrangea tree is done the same way.

Hydrangeas that bloom on old wood should only be prunned after they flower...do not prune in the spring or fall you will cut off flowers for next year.

Actually, Hydrangea Limelight is a paniculata. These you cut to the ground late each winter. They bloom on new wood and will reach 4 feet or more by late summer when they bloom. It will also take full sun, although I have it in part shade in my hot garden. It's a real beauty! (Easy to start from cuttings, too.)

Sorry can't pick only one. Tunic Flower, short 3 inches or so pink baby's breath like blooms, starts in June and goes all summer, Heliopsis- Summer Sun about 3ft. starts blooming in late June and goes till frost another newer variety of Heliopsis- can't think of the variety and to dark to go look, about 18 inches in height also blooms all summer. Shenandoah Switch grass 3-4ft, Blue Heaven (I think) Little Bluestem about 3 ft. and of course Lilies, starting with the martagons in spring, then the asiatics and LA's folled by the trumpets and orien-pets. White Butterflies blooms for over a month and Scheherazade is absolutely stunning.

Mines got to be Asclepias curassavica,with its red and gold flowers.Although it blooms late in the year compared to other perennials,it's definitely worth the wait.I have some mixed with Celosia,''Imagination''Verbena,and Salpiglossis.

I also think Asclepias curassavica is a stunner, although for me it's an annual. But, the advantage of that is buying it in bloom in late April and having it bloom nonstop for the next 7 months - never a gap, it's unbelievable.

- Steve

Shasta Daisy "Becky"
Veronica "Sunny Blue Border"
Coreopsis "Zagreb"
BES "Goldsturm"
Sedum Autumn Joy

All common, simple plants but I wouldn't want to be without them.

What used to be called Aster laevis 'Bluebird.' Its foliage is an attractive blue-green all summer. Then late in Summer it starts blooming and goes for a very long time in Fall. The foliage turns bright red also in Fall. No nasty mildew or disease problems like the New England Asters.

Mine would have to be Jacob Kine Bee Balm (hummingbird magnets) or Indigo Spires Salvia. If I must choose one it would be the Indigo Spires. There are photos and more favorites of mine at the attached site.

Here is a link that might be useful: Perennial and Rose Gardening Site

Asclepias tuberosa is one of many favorites. The foliage always looks good and it usually blooms twice. It's 2' or less I think and carefree for me. I have well drained sandy soil. Reseeds a little.

Tough question!
Achillea- Walter Funcke
Catmint- Walker's Low- extremely hardy and tough, great little blue- purple blooms- bumble bees love it
Echinacea Harvest Moon- golden color & pleasant scent
Galliarda- Golden Goblin- 3 ft- the yellow petals drop leaving a fuzzy yellow pom-pom behind
Lantana- the one that is bright yellow and bold red
Gardenias.

Any of the ornamantal GRASSES.

I really like Maiden Grasses.

Here is a link that might be useful: Perennial and Rose Gardening Site

Here's my list of winners:

Salvia May Night
Scabiosa
Dianthus
Knockout Roses
Coreopsis

My May Night Salvia was awesome this year. I bought it last fall at Lowe's when they were clearing out plants. It started blooming in early May and just has not quit. I deadhead it and it just keeps going.

Moonbeam Coreopsis and Creme Brulee Coreopsis have both been in bloom almost as long. And planted next to the May Night Salvia, they make a striking picture.

Linda