Peonies can live 100+ years. Own root roses - 20+ years.

Not knowing what you have in your garden, can't speak for anything specific. If some were originally planted six years ago - you know those last at least 6 years. By dividing, reseeding, spreading - what you have could potentially last forever.

My inherited gardens were originally planted in 1972 - and I still have the garden plan as well as the original tall bearded iris, garden phlox, Silver Mound artemesia, Siberian iris, pink baby's breath, peonies, veronica, nepeta, coral bells, daylilies, balloon flowers, oriental poppies, Northern Lights series of azaleas, ferns, hostas, trollius, astilbe, bleeding hearts, Oriental and Asiatic lilies as well as true tiger lilies, plus more I'm sure I'm forgetting.

Many/some have been divided, respaced, relocated, thinned out, added to over the years - but that's the beauty of perennials - I've still got the same backbone plants 37 years later.

Trees, shrubs, and conifers are long-lived. The lilac hedge that hides my property was planted in 1900.

I'll approach it from the other direction. There are perennials that I just plan to re-plant every few years. Here are some of the things that are *short* -lived (in my garden, anyway):

Delphiniums
Flax
Scabiosa
Dianthus
Shasta Daisies
Coreopsis

Pasted from the HGTV site...

'Long-lived perennials

"I just helped a friend move a peony that's 125 years old. Her great-grandfather had planted it," says perennial expert Stephanie Cohen, whose new book The Perennial Gardener's Design Primer is already into its second printing.

Given the right place and the right care, these plants will typically live at least 15 years, and some a lot longer than that.

# peony
# hosta
# bearded iris
# Siberian iris
# daylily
# hellebore
# euphorbia, spurge Euphorbia
# red-hot poker or torch lily (Kniphofia)
# monkshood (Aconitum)
# bugbane (Cimicifuga)
# gas plant (Dictamnus)
# balloon flower (Platycodon grandiflorus)
# false indigo (Baptisia australis)
# lily-of-the-Nile
# astilbe (Astilbe)
# purple coneflower (Echinacea purpurea)
# black-eyed Susan (Rudbeckia fulgida)
# Helianthus
# butterfly weed (Asclepias)
# goldenrod (Solidago)
# bee balm (Monarda)
# goatsbeard (Aruncus)
# ironweed
# Joe-pye weed (Eupatorium)
# sneezeweed (Helenium)
# sedum
# trillium

Short-lived perennials

These plants typically last for three to five years before fading away, or "the plants that live for three years if you don't kill them first," says Cohen.

# columbine* [but they reseed a lot]
# scabiosa
# wallflower (Erysimum, or Cheiranthus)
# basket-of-gold (Aurinia saxatilis)
# hardy mum
# lupine [collecting and starting more from seed is easy]
# leopard's bane (Doronicum caucasicum)
# feverfew (Tanacetum parthenium)*
# geum
# cardoon
# fire pink (Silene virginica) and many other pinks
# blanket flower (Gaillardia)*
# Coreopsis grandiflora, C. lanceolata*
# lavender
# Phlox divaricata*

* reseeds freely

:-)
pm2

The problem with lifespan is that it is so dependent on many factors that vary with site as well as other variables that what lives long for the person across the street may die out in your own yard for, well, many reasons. My 'butterfly blue' scabiosa is long lived for me but I appear to be one of the few people this holds true for.

Peonies are a good example of a really long lived plant, as well as anything that survives on abandoned properties for a period of time but the ability to survive on neglected land almost has more to do with competitiveness than longevity itself.

So... ask around your area. People who have similar conditions to yours are the best to ask, and since I don't know what kind of conditions your garden has I cannot give you any definitive answers. Even peonies can be short lived if sited wrongly.

That said, some long lived plants for me (in case they may also be for you) are Baptisia, sedum, and mother-of-thyme.

Thanks so much. I copied all and put it in a file. I also printed it out for my 4 newbies. I'll keep checking back here for any additions. Wow, got to get some Peony in the garden. It is so encouraging to see old beauties come back every spring. A Peony and I can grow old together. lol

I transplanted a peony into my yard 3 years ago that my grandmother planted sometime in the 1940Âs. Even though I did a rotten job digging it up in an overgrown garden full of weeds, basically ripping it out by hand in a hurry before the place was sold, it is doing well and has bloomed the last two springs. Amazing plants. I wish I had taken more but did not have the opportunity.

Found this in a google search for 'short-lived perennials.' I'm sure there are other, more extensive lists, or ones with actual time-frames, but this was the first one I clicked on.

Here is a link that might be useful: Iowa State Listing of Long- & Short-Lived Perennials.