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exactly how much cold does my peony need?

18 years ago

My double pink peony had six beautiful blooms this year. I realize I live in the wrong zone but I am determined to have blooms next year. I have thought of putting a foam ice chest (with the bottom cut out) over the plant and then I could take the top on and off to add ice as needed on the ground to simulate cold weather. My question is, how many hours of cold does it need and when? (what month or months?) Please humor me. I am treating this as a wonderful experiment and I hope it works!

Comments (21)

  • 18 years ago

    I must ask....where did the plants come from? Did you buy the plants in California, were they raised in California?

    If this is the case, you have bought a plant hardy to your local zone....and need not have the winterizing that you have evidently heard about from northern residing posters.

    A palm tree, doing well in your locale, could not, be expected to do well in a northern zone. Palms are hardy to the warmer zones.

    A peony, raised in ....say Toronto, Ontario....could not be expected to survive transplanted to Ontario, California.

    If you bought a California raised peony, then that plant should be able to sustain itself in California, and be over-wintered however that implies.

  • 18 years ago

    "15. Can I grow herbaceous peonies in a warm climate?
    The short answer is a qualified yes.

    Having always lived in northern climes I can't speak from personal experience, however herbaceous peonies are generally considered to grow well into USDA Hardiness Zone 8.

    The factor limiting the success of peonies in warm climates is the requirement for a cold period to overcome a seasonal dormancy. There is no well-accepted data available that states exactly what the requirement is in terms of temperature and duration.

    There does however seem to be consensus that weeks of freezing temperatures are not required. There have been several reports from gardeners in USDA Hardiness Zone 9 who have grown peonies successfully.

    Peonies grown in warm areas will benefit from slightly more shade than those grown in cooler climes."


    Peony seeds generally require 2 months in the fridge to break dormacy...

    from Mallorca or
    from Crete are more suited for a hot mediterranean climate, you could perhaps try them if the lactiflora-cv. fails, they are both easy from seeds.

  • 18 years ago

    If you have bloom this year you should have bloom every year. The way to improve your cooling hours is to keep the top of the root at ground level. In California the air temperature will have more hours below 45 degrees than the soil temperature. I have many varieties of peonies, all of which bloom, none of which were from California grown stock. Al

  • 18 years ago

    >A peony, raised in ....say Toronto, Ontario....could not be expected to survive transplanted to Ontario, California.

    I disagree. Paeonia lactiflora grows wild in China, and a lot of the cultivars avaliable were bred in France; but that doesn't mean they only thrive in China and France. And secondly, just because a plant is bought at a local nursery does not mean that it will thrive in your garden. Many times the plants have been raised in greenhouses, other times they have been bought wholesale from other nurseries miles away.

    Take advantage of all the excellent mail-order nurseries, and have fun stretching the hardiness zones! :-)

  • 18 years ago

    I purchased my peony from a nursery in Newhall, California near Magic Mountain. The girl who sold it to me said that it had been refrigerated from the grower and that I would get blooms this year but probably not next year because we don't have enough cold time. That's why I wanted to simulate a longer prolonged cold spell.

  • 18 years ago

    Hi, Just wondering if you are still planning on simulating cold weather...I live in texas and love peonies, wat to see if your experiment works!

  • 18 years ago

    Yes, I am going to try it. I'll let you know what happens. The leaves on my peony are turning brown. Are they supposed to do this?

  • 18 years ago

    I'll be interested to see if your experiment works. Good luck!

  • 18 years ago

    Your peony should not be going dormant and have the leaves turning brown at this time of the year in California. Are you giving them enough water? In very hot weather you may get a little sunburn but if they are getting enough water the sunburn would be minor. When I cut mine back around thanksgiving they are just yellowing and getting limp. Al

  • 18 years ago


    I remembered reading your posting and while I was meandering around a bit on Google looking for sources of peonies, I happened to notice an aritlce about the number of chilling hours.

    Thought you might find it useful/helpful in your endeavors.

    Good luck and my best wishes.


    Here is a link that might be useful: Peonies for the Home Landscape

  • 18 years ago

    Thank you all for your support. Bill, that site was just what I needed. I put it in my favorites. Al, the brown leaves may be sunburn because the leaves that are protected are still fresh and green. Next year I will try to protect it from the too hot sun. My double pink does get plenty of water. Luvahydrangea, I'll let you know if it works. How far do I cut them back? To the ground? I have so many questions!
    Thanks again,
    Janet (dppeony)

  • 18 years ago

    Silly me. If I had read completely to the end of the site that Bill had suggested, I would have read that my peony needs to be cut to 3 inches from the ground. Do you all concur? Not that I'm silly, but about the 3 inches?

  • 18 years ago


    As you remember, the pertinent sentence gives the reason - "to eliminate the possibility of the fungal diseases overwintering."

    "In the fall, after a heavy frost, remove and destroy the stems of garden peonies down to 3 inches from the soil surface to eliminate the possibility of the fungal diseases overwintering."

    Given the fact that this information comes from the North Carolina Cooperative Extension service and given the fact that the climate in North Carolina can be rather humid - thus aiding in the fostering of fungal disease - I believe it to be good advice - even though you might live in a drier climate where fungal diseases might not be a great or moderate matter of concern.

    Of course, not only should you cut the stems/leaves down, but you should be certain to remove them from around the plant and toss them into the garbage.

    I used to live on the tallgrass prairie of central Illinois - Peoria and now live in northwestern Michigan - Manistee. The humidity here in Michigan is somewhat less than in Peoria - especially during the summer, but the fall season can be a little wet in both places. Accordingly, I would follow the advice for our neck of the woods.

    I think it might be wise for you to do the same unless you hear otherwise from Peony growers in climates similar to yours.

    Again, best regards in your gardening efforts.


  • 18 years ago

    I usually cut mine down to about 6 inches. I have no fungal problems but my peonies are planted so high the buds are exposed all winter and the stiff dead stems left at 6 inches gives the delicate buds good protection from night critters such as skunks,raccoons and possums digging for grubs and from my cats digging for you know what. Al

  • 18 years ago

    I guess I will cut mine down to 6 inches. My cats stay indoors but it will allow the buds protection from neighborhood cats. - Janet

  • 13 years ago

    Allan Rogers in his book "Peonies" Says that about 400 hours of cooling is usually considered the minimum cooling required for peony to bloom. If you call your county extension service they will tell you what the average hours of winter chill you can expect where you live. If you buy your peony as a bare root plant, I would plant it in a one gallon container for the first year and plant it in the ground at the start of the rainy season(here in California). When you do plant it in the ground make sure NOT to bury the little red buds for next years bloom stalks underground. Sarah Bernhardt is one of the strongest growers and a good one for the first. At the end of the season when I remove the spent foliage I will often spray the area with Bordeaux mix if I have had any sign of fungal disease. Yesterday I sprayed again those plants that showed signs last year. I also add a couple of inches of compost around, not on top of the plants. Al

  • 13 years ago


    I strongly advise agains Sarah Bernhardt. I see you are in zone 9...I am in 8b...perhaps 9. Sarah is a late should go with early types. I have had Sarah in my garden (san jose, CA) for 25 years and it is the poorest performer of my 15-20 peonies. It is an industry standard, but not for warm climates.

  • 13 years ago

    Nhulburg your Sarah Bernhardt must have something wrong besides the heat. The Napa valley is as warm as the Santa Clara Valley and Sarah does fine here. The only peonies I limit from full sun here is the tree peonies. Al

  • 13 years ago

    Al, before too many readers begin to believe you can plant sub-tropical perennials in northern climes the old adage is still one to go by.
    "You can take the girl out of the country.....but you cant take the country out of the girl."
    Meaning, plants do have their zones and if one wishes to avoid disappointment and save something from their pocket, plants bought and raised in their localities where nurseries operate, are their best option.

    Nurseries do not make a habit of stocking plants they cant sell or, if sold, have short lives and the buyer returning same to get refunds.
    So nurseries stock what is hardy to their locale--it just makes good economic sense.

    The peony that d p raised back in '05, (hopefully is still alive and kicking) must surely have been raised in a warm needn't have been California; Mexico is close at hand, Nevada, New Mexico and Arizona are also possibilities.
    The ideal potted plant is one that is hardy to two zones colder. Thus the peony bought in sunny California's zone 9, should be hardy to zones 8 & 7.
    If one believes that, Oregon, Utah, Colorada, Washington and Idaho might have been its natural home.
    And whether warm climate or not, all plants have a dormant period--a time of rest.

  • 3 years ago

    Great idea! Thank you for sharing!