The big plant producers- hybridizers- keep coming out with "new and improved" everything. They seem to be concerned with lavish, double, gargantuan non stop blooms in an endless array of colors, and not with hardiness or longevity. I've tried numerous new and expensive cultivars, and found many to be short lived and unreliable as far as winter hardiness is concerned. Caveat emptor. Here are a few notes on some of my plants which you may find helpful.

Achillea filipendula is the most long lived and reliable of the Yarrows, but it still may last only 5 years or so. Keep your eye out for scattered seedlings to replace the parent.
 Aconitum fischeri- nice autumn color, foliage is the best of the Monkshoods, DON'T eat- poisonous.
 Ajuga-  Deer resistant, tough ground cover, spreads aggressively.
Alcea ficifolia- This true perennial Hollyhock is supposedly rust resistant, NOT true!
Alchemilla mollis- Long lived, common, carefree Lady's Mantle does best in partial sun.
Allium tuberosum- Nice late season white blooms on the Garlic Chives, but self sows aggressively. Deadhead it unless you want hundred of seedlings.
Anthemis tinctoria-  Sometimes called Golden Marguerite, this one blooms forever if deadheaded, but you need to leave a few flowers to self sow and replace the short lived parents. Give it average soil.
Aquilegia- Columbine seem to perform best for me when they self seed themselves into places where I would not plant them!
Armoracea- Never rototill in Horseradish, or you'll end up like my father did with hundreds of plants!
Artremisia schmidtiana- Silvermound -I've given up on these because of their unreliability overwintering.
Asclepias tuberosa -Butterfly weed likes full sun and well drained soil- never wet feet in winter.
Asclepias incarnata- Unlike tuberosa, the Swamp Milkweed loves wet soil and will grow in shallow water. All Asclepias are host       plants for Monarch Butterflies, and are honeybee and butterfly attracters.
Asters- Nice late summer flowers, also bee and butterfly attracters.
Astilbes- Nice foliage, not long bloomers though. Moist soil a must.
Baptisia -The species Baptisia is long lived- my plants come from a parent plant 70 years old! The newer expensive cultivars have given me some trouble.
Buddleja- Butterfly Bush is an incredible butterfly attracter, but its longevity is impossible to predict. It may live 1 year, maybe 5, but seldom more. I'd never recommend paying more than 5 bucks for one.
Campanula glomerata- The Clustered Bellflower is a strikingly beautiful purple blue, but the foliage looks like crap afterwards, so hide it behind something that grows taller.
Campsis - The vigorous rugged Trumpet vine. Keep it trimmed or give it plenty of room- no wimpy trellis. Hummingbird magnet.
Centaurea montana -Perennial Batchelor Button. Nice in bloom, but cut it back after, as the foliage is messy.
Chelone - Turtlehead is a nice mid-late-summer bloomer. Rugged, long lived, will grow in shallow water.
Cimicifuga racemosa-  Bugbane, native, invasive over time, don't plant it near a window, as the flowers don't smell good.
Cimicifuga "Brunette"  Late blooming, a bit pungent, give it a mix of sun and shade for best purple foliage.
Convallaria- I often forget my Lily of the Valleys are in bloom only to be reminded by their wonderful fragrance that fills the air. Invasive though, and tough as nails.
Coreopsis "Zagreb" I wish the hybridizers would use this one in their work- it is extremely hardy, vigorous and long lived, much more so than "Moonbeam" or "Rt. 66", both of which bloom longer though. I've tried a number of other cultivars which were unreliable wintering over.
Corydalis lutea- extremely long bloomer for mostly shade. Self sows.
Corydalis sempervirens- A native biennial that likes full sun, average to poor soil. Self sows nicely. Hummingbirds.
Darmera- Damp soil a must for the Umbrella Plant. Early flowers on single stalks before the huge leaves.
Delphiniums- I have given up on these beauties because of disease problems mostly, also longevity. 
Dianthus "Firewitch"- Fragrant, long lived, nice foliage, full sun.
Dicentra spectabilis - The foliage of Bleeding Hearts turns yellow early, so hide it behind something that grows taller later.
Digitalis purpurea- The common Foxglove is biennial but usually self sows prolifically. You need to save the babies as replacements- don't go crazy mulching or weeding.
Digitalis lutea - This perennial Foxglove has less dramatic yellow blooms than its cousin, but it attracts Hummingbirds like mad.
Draba -Early mat of yellow blooms, first Spring flower in sunny spots.
Echinacea- I've tried several of the newer expensive Coneflower cultivars and have been disappointed by their unreliability overwintering. I stick with the species purpurea, and  the older cultivars. I am trying a seed variety "Green Twister" this year....
Epimediums -  The Barrenworts are great shade plants, even in dry shade. Short flowering time but good foliage. Rugged.
Eupatorium -Joe Pye is a nice, tall, late lavender bloomer. Atracts a lot of pollinators and likes wet feet. Sturdy too.
Ferns- I appreciate all of them for their foliage, longevity, and ease of culture.
Geranium "Rozanne" All the Geraniums are worthy plants- "Rozanne" may be the longest blooming perennial to be had. A bit floppy though.
Gillenia- Bowmans Root is an unappreciated little known plant. Attractive foliage, 2 and a half feet tall, delicate white flowers of short duration. Partial shade.
Grasses -I keep repeating myself, I like the grasses. Spring, summer. fall into winter. Foliage, seed heads. color, form. For the shade, Carex "Blue Zinger" and Hakonechloa  are my favorite contrasting blue/yellow grasses.
​Heliopsis h.- Long bloomer. Red aphids can be a problem, but they are easy to kill with soapy water or neem.
Heliopsis s. "Bleeding Hearts"  I started them from seed last year- I'm crossing my fingers that the hybridizers didn't breed them from wimpy parents, and that they make it through the winter. Foliage is purple and flowers are red and bronze.
​Hellebores- I'm restricted to growing my own seedlings and divisions as the wholesale price of plants has exceeded $5. Hellebores are among my favorites- attractive evergreen foliage, early and long lasting flowers, reliable and deer resistant.
Hemerocallis- If you want some newly released variety of Daylily, you'll need to buy them elsewhere, as the cost of these are sky high. I have a pretty good selection of plants though, and Daylilies are hard to kill.
Heucheras- Coral Bells are an enigma to me. I'll put 50 plants in shade, 50 in sun, and 50 in a mixture, and I'll have a whole array of different success rates. In each bed, some plants will be fantastic, some will be o.k., some will look like death warmed over, and some will die! Can't figure them out.
Hibiscus-  The last perennial to emerge from hibernation. Be patient. Don't dig it out thinking it's dead.
Hosta- You can't kill a Hosta. I have a fair selection-25 or so- but again, if you're looking for a newly released cultivar, look elsewhere, as the new varieties are way too expensive when first released.
Hydrangea a.- This slow growing vine has beautiful bark and white flowers when mature.
Inula r. - A ten footer! Late yellow blooms, doesn't mind wet feet, but it does self sow a lot.
Iris germanica- Well drained soil a must for these old fashioned standards. I have 4 labeled colors and some are a mix.
Kirengeshoma  with yellow bells at 4 feet, and Kitabelia 6 feet in white are both shade lovers with maple leaf foliage.
Lavandula a. "Phenomenal"- I'm trying a new Lavender this year. Supposed to be hardy and 3 feet tall....
Leucanthemum "Becky" -A very sturdy upright Shasta Daisy that doesn't flop in rain or wind.
Ligularia -  All the Ligularias like morning sun, afternoon shade. Slugs attack "Desdemona" and "Brit Marie Crawford"- I spread a non-toxic slug bait contains iron phosphate as soon as the snow melts and once or twice a month after that. Ligularia fischeri blooms in September, October.
Lobelia cardinalis -The native Cardinal Flower needs wet soil or to be underwater to overwinter well. Along with red Bee Balm, it's the best hummingbird magnet.
Lobelia syphilitica - Great Blue Lobelia self sows prolifically.
Lupines- A nostalgia plant for many, its huge demand is the only reason I grow it! They're short flowering, have unattractive foliage after flowering, are aphid magnets, and need to reseed themselves to replace the short lived parents.
Lychnis coronaria- Biennial or short lived perennial, you have to let Rose Campion self seed and take care not to weed out or mulch over the replacement seedlings.
Monarda d. "Gardenview Scarlet" - My favorite Bee Balm. It loves to be divided and moved every 2 or 3 years. Loves compost. Hummingbirds love it. I keep trying new cultivars and am disappointed by their lack of vigor and unreliability over wintering. Trying "Blue Moon" this year....
Myositis- The Forget-me-Not is a biennial which seeds in reliably unless you mulch heavily or weed out the babies. Let it do its thing, sun or shade.
Nepeta "Walker's Low"- This is Catmint, not Catnip, but desperate cats are sometimes attracted to it.
Pachysandra t. - A slow growing (at first) evergreen, shade ground cover that eventually becomes aggressive.
Papaver orientale - I'm done growing and selling Oriental Poppies. Customers have a hard time growing them in spring and no one wants to buy them in September when they should be transplanted.
Paeonia- Peonies are increasingly hard to sell at $5, as they're slow to divide, slower to grow from seed, and wholesale prices keep rising. Long lived and sun loving, plant the 'eyes' 2" below the soil surface and leave them alone for 10 or 20 years. Don't fret about the ants, they're not hurting a thing.
Penstemon "Dark Towers"- A favorite of mine, nice purple foliage from May to October, pink flowers.
Perovskia - Full sun for the Russian Sage, average  soil. Slow growing. Some folks have trouble with this one.
Persicaria bistorta "Superba" - Nice pink bottlebrush blooms, likes partial sun.
Persicaria polymorpha- At 6 feet tall or so, give it some room. White plumes over a long time. Sun.
Phlomis t. -Unusual donut like lavender blooms on tall stems and nice foliage, Partial sun.
Phlox paniculata- All my tall Phlox are mildew resistant. I have two of my own propagated varieties which bloom very late- September.
Platycodon- Balloon flowers need well drained soil. Long blooming, long lived.
Primula-  I like all the Primroses. P. heucherifolia seems to grow best in compacted soil! P. japonica must have moist to wet soil. P. "Francesca" has the most unusual green and yellow long lasting blooms. I have had a red/yellow polyanthus variety for about 35 years now!
Pulmonaria- I like the Lungworts too. They have crossed pollen in my gardens for 25 years, so I have a lot of plants with differing silver spots and overlays, with blue, pink and occasionally white flowers. Hummingbirds visit them immediately on their return from the south.
Rodgersia- A slow growing shade lover with huge leaves, the Rogers Flower is another of my favorites. Long lived, low maintenance.
Rudbeckia fulgida f. -Long lived, long flowering Brown Eyed Susan.
Salvia transylvanica- Unlike most Salvias, this species has an open airy habit.
Sanguinaria- The Bloodroot is very early blooming. Unfortunately the bright white flowers don't last long. Odd foliage, native, and I have a very limited number of double ones.
Sanguisorba- White spikes in September, attractive foliage, and the Canadian Burnett will grow in wet soil.
Sedum- Most like well drained soil in full sun. All attract honeybees. "Angelina" is gorgeous, appearing with orangy/bronze foliage when the snow departs. "Autumn Joy" is classic, common, but very reliable.
Silene armeria is a biennial that self seeds prolifically. I've had it in my gardens for over 35 years!
Silphium p. - Yellow daisies on ten foot stalks in summer. Seldom gets floppy. Goldfinches can't wait for the seeds to mature.
Stylophorum- This plant appeared in my gardens one year from who knows where. Nice foliage and flowers.
Succisa p. -Nice plant, shade or sun, lavender round heads in August, September. Bees and butterflies.
Tanacetum p.- Feverfew self seeds prolifically, long bloomer of small white daisies.
Telekia- A fast grower reaching 5 feet and flowering gold/yellow in June. I cut the flower stems back when they're done and the plant puts out huge attractive basal leaves. Sun or shade, bees and butterflies.
Tradescantia- This colorful Spiderwort propagated itself in my gardens a few years back. It's a beautiful blueish purple, and it doesn't spread rampantly like some varieties. Long blooming.
Tricyrtis h. -The common Toadflax blooms beautifully in September, October, but needs to be seen close up to be appreciated.
Verbascum c.- Long blooming yellow or white spikes with purple stamens, the foliage on this Mullein is coarse. Part shade or sun, it is a Bumble and Honey Bee magnet. Early in the morning, I can hear their buzzing on it from 20 or more feet away. Flowers close in the afternoon.