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what are the hardiest perennials

Posted by sweetleelee 4 WI (My Page) on
Sun, Jun 27, 04 at 15:02

We are in northeastern Wisc and can have some long cold spells, well below -10 for days at a time. I have had only middling luck with my perennials. Coneflowers, red sedum, yarrow, black-eyed susans have done well; hollyhocks don't do particulary well for more than two seasons (they come back but do not bloom, even with fertilizer); and some ground covers have flourished. Larkspur, delphinium, carnations, peonies, etc, limp along, but after a brutal winter many things don't come back. Day lilies have done well in an area protected from the winds we have here. Suggestions, anyone, for the hardiest perenniaal varieities, preferably that bloom for a long period? Last year I tried some 'winter hardy' asters from Walmart that were supposed to be formulated for our area, but they didn't come back. I am trying to get away from annual planting, and develop a really resistant and sturdy perennial garden. The soil is rich and well fertizied and I try to follow instructions for mulching and covering different varieties, but I clearly need some help. We have some large shelter pines and low evergreens that afford some protection in the winter but the winds in our area are particularly forceful and unrelenting, and drop the wind chill down even further. We are seriously out in the country here and skunks will dig through whatever they must to get to bulbs. I have given up on bulbs as I would spend all my time fending off the wildlife, which is more resourceful than I am. Help.


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RE: what are the hardiest perennials

  • Posted by Mytime 3/4 Alaska (My Page) on
    Sun, Jun 27, 04 at 18:20

Wind chill doesn't affect herbaceous perennials--they are below ground. I can't imagine peonies and delphinium not doing well for you unless there is a problem other than cold in the winter. I'm linking a site that has plants proven hardy in way worse weather than yours. I grow many of those plants here (I'm further south, and warmer in winter than in Fairbanks, but colder than you), and can attest to their cold hardiness. I don't know how they would hold up in your heat (I think you get warmer for longer than us).

Here is a link that might be useful: plants for fairbanks, alaska


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RE: what are the hardiest perennials

sweetleelee- if your winter lows are in the -10 range you would be in Zone 5. I suspect if you are in northeastern wisconsin your zone is more like 3 or 4.

I live in Zone 3a where winter lows are -40 and we also have the 'brutal winds' out in the country. All the plants you listed do extremely well here with the exception of Carnations. They should also survive and exhibit vigor in your area.
Here are a few plants that are among my favorite. They are bone-hardy and grow like weeds. For the sun - Salvia nemerosas, Heliopsis, Ratidiba pinnata, Delphinium grandiflorum 'Blue Butterfly', Linum perenne, Lupine, Iris, many of the hardy Geraniums(cranesbill) Phlox paniculata, Phlox subulata, Asiatic Lilies, Euphorbia polychroma, Nepeta, Veronicas (many varities) Monarda. For the shade - Ligularias, hostas, Chelome, Monkshood, Bleeding Hearts, Astilbe, Goatsbeard.
None of the plants listed above need to be covered over with mulch for the winter. In fact, covering plants with mulch can sometime be harmful if the mulch is put on too early or taken off to late.
A comment on Hollyhocks. Most are biennals and so after they bloom they do not reappear. They are prolific reseeders. So perhaps the hollyhocks you see the year after blooming are the 'new' plants that do not bloom the first year.
Walmarts tend to carry the same plants nation-wide and so it is rare they have plants specifically suited to zones 3 & 4.
You said your soil is rich. Is it clay, sand or loam? High and dry ground or low ground that tends to stay wet? Have you have had the soil tested? What is the PH? The acidity/alkalinity of soil can be a major factor in plant growth but would have to be significantly out of the normal garden range of 6.0 -7.0. Also, you mention the brutal winds. I am assuming these are winter winds? As Mytime said, windchill does not affect dormant perennials. How much snow cover do you normally get? How about the summer winds? Summer temps? In the 70's most of the time in a 'normal summer'? Are you close to Lake Superior?
Do your plants have adequate moisture if there is no rainfall? The performance of perennials is directly linked to the amount of water they receive.
Perhaps a little more info might help with a 'diagnosis' Folks on this forum would love to help. It sounds like you put a lot of work into your gardens and certainly deserve to get great results.
Jan


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RE: what are the hardiest perennials

Hi--
Thank you for your responses. Here is some more info.
My main problem has been that since our snowfall has started to come later, I have had a very hard time getting my perennials well established enough to flourish the following year. Those cultivated prior to the change in weather have generally done well, but some are beginning to look stressed in the spring and are not doing as well as before. Nothing is older than 10 years.

Climate: We are in a damp hollow, but we do get some weeks of 90+ drought in the summer.
First frost: Mid september, with a killing frost by the first week in October.
Our snows have come later and later each year. Our ground is frozen hard by November, but no real snowfall until January. We are 0 to -10 for several weeks, with some periods of -20. Our snow has become drier as it has come later, with blizzardly pile ups and dry spots. We typically have a false spring or thaw in February, followed by more freezing temps. We have had heavy wet snow and ice storms in March and April the past three years that have destroyed some of our beautiful tree and shrubs. The temp starts to modulate in mid to late March, with a very, very slow warming. We had our last frost this year on May 28, with 28 degrees. Last night, June 27th, the low was 48. We are windier here than anywhere around here, and although everyone jokes about it, no one has ever explained it to me. We are located in a large cleared valley in the woods, primarily in logging country, 90 minutes north of Green Bay close to the Wisconsin-Upper Michigan border near the Menominee River.

The soil is very poor. A local farmer subdivided his corn fields and sold them off as lots. He apparently had never heard of fertilizer or crop rotation. We have a scarce 1 inch of sandy topsoil, then very, very sandy light brown earth for four to six inches, then hard pack clay that affords no drainage at all. This reddish clay will hold it's shape if you squeeze it in your hands, but I think it is not very amenable to living things. There are very few roots down there and no worms.

All my plantings are in three high foot enclosed raised beds that I have filled with the following 5-part mixture-- 2 parts brand-name topsoil, 1/2 part commercial cow manure, 1/2 part coarse sand for drainage, 1 part peat, and 1 part compost. I use an Envirocycle composter that makes a fine quality clean compost and I use the 'tea' as my plant food. It is always applied to the roots, never on the plants themselves. This is basically what I have always used on my plants, except this outfit makes it just heaven, it is so easy to use and everything is broken down uniformly. When varieties call for sandier soil I increase the sand in the mix until I am satisfied with the speed of drainage. Overall the beds are well drained and I keep the beds moist when the weather is dry, but nothing is ever soaked, unless nature does it. The beds are all on a very slight angle and enclosed by loosely fitted posts, so there is plenty of drainage out of the beds for moisture. The soil feels rich and looks very dark because of the compost, but it is never mushy or dank. There are sunny areas and shady areas and things are planted accordingly.

I mulch with clean straw. I don't mulch everything, but if the directions called for it originally, I do it. I mulch after cutting back the plants and after the first hard frost. I dig down in the snow as soon as I can in March and clear a space for the plant to 'breath'. All of the mulch is discarded in the spring and I never use leaves or plastic or anything like that, just clean bedding straw.

I am wondering if the freeze-thaw process is destroying the roots of my plants. I know the ground is freezing harder without the early snow cover because for the first time that we have lived here, the line to our septic system started to freeze over four years ago, and we had to have it re-dug deeper to keep that from happening. Still, what do I mulch? Do I mulch everything? Even my well-established plantings are suffering. My salvia, (which I do cover because the patch is so exposed) which is six years old and beautiful, and was in a patch about six feet long by three feet across, has been shrinking. The center is doing very well. The areas around the outside just didn't come back and the size is about one foot smaller all the way around. This has happened slowly over about three years. Lots of things seem to take hold well through the course of the summer and then limp along the following year or never come back at all. My spearment, red sedum and hens and chicks (sempervivum) are indestructible. Yarrow does very, very well. Lilies seem to thrive, if I can keep the rabbits and deer away, but the last of my delphiniums are gone, the larkspur that I planted last year did not come back, my beautiful, beautiful butterfly bushes, and my rosy coreopsis have just decided not to come back anymore. I am having a dreadful time with my little rock garden and I am replanting that every spring now. That I think must be from the frost because there isn't enough room maybe for the roots to go deep enough?

I have never done a soil pH. I guess I will have to do that.

Is it the frost do you suppose? I see no evidence of rot. Nasty destructive bugs aren't crawling all over above or below the surface. Things aren't turning yellow or getting spots or getting eaten up. The roots of dead plants that I pull out of the ground are big but they seem crumbly somehow. Would frost do that?

My neighbors are not flower gardeners, so I can't really check out what is happening to them. Some have vegetable patches with a few hanging flower baskets, that sort of thing. They don't understand wanting to grow a butterfly garden because they say the butterflies will come around anyway, right, and frankly several of them think I am nuts. (I do spend a lot of time in my garden.)

I went as far as to ask the local extension office in Escanaba, but they gave me instructions for such heavy and prolonged mulching and covering that it can't be right. I would have rot and beetles and who knows what if I followed their instructions.

Well, I'm open to suggestions of any kind. I'm stumped and what's happening to all these beautiful plants is making me very sad.


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RE: what are the hardiest perennials

Interesting situation.... I have a few comments but I'm not sure how helpful they may be!

From your description of the area, it sounds like the winds are high because that cleared valley would channel winds through it at higher speeds than in a valley clothed with trees! A 'damp hollow' in the bottom of a valley is also a serious frost pocket so you probably are effectively in a colder zone than areas outside that valley! The soil mix in your raised beds sounds good. Raised beds do tend to freeze faster in fall/winter and warm earlier in spring so you might want to plant things not too close to the edge of the beds where they are less insulated from freeze/thaw effects. You talked about larkspur - that term is usually used for annuals so you would not expect that they would come back. You should make sure you buy perennial delphiniums. The Magic Fountains ones are good sturdy ones for windier areas but you'd still be best to stake them!

I never cut back perennials in the fall, other than things prone to mildew or other fungal diseases (cut down the peony foliage...!) Leaving the foliage on until spring may be a little less attractive but it helps capture snow and offers some insulation during winter. It's the only mulching I do apart from leaving fallen leaves or pine needles on the beds. I only start spring clean up when the majority of things are clearly growing and it looks like the worst of the frosts are past. It would probably be best to stick to extremely hardy plants - say, hardy at least to zone 3 - just to be doubly sure that they have a good chance. The list of plants for Fairbanks is a good place to start!

Good luck with your garden.


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RE: what are the hardiest perennials

Woody is absolutely right about the beds freezing faster and I never thought of that. A lot of the perennials I have lost are along the outer edges. The biggest bed is against the south side of my house and is five feet wide, but it is thirty feet long, so that is a lot of exposed edge. I was thinking that it was that cold wind blowing that was dropping the temperature but those beds are effectively open on three sides to the cold. I'm thinking I can relocate a lot of things towards the back nearer the house where it is warmer. In the fall I can get some bales of straw and bank them against the outside walls of the beds for some insulation and I guess I will be looking for hardier varieties of everything. Thank you!
Lee


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RE: what are the hardiest perennials

  • Posted by Mytime 3/4 Alaska (My Page) on
    Mon, Jun 28, 04 at 18:28

I would suggest not digging in the snow in March. Snow insulates against those spring freeze-thaw cycles that can kill new growth. Your plants don't need your help to breathe. You also then open it up to solid ice forming over your plants, and that can damage them. Sometimes you just have to let nature take it's course and be patient. Years when you have solid freezes for months before snow cover arrives will yield more dead plants. In years like that, it is my rock garden that suffers the most (whether it's the more shallow roots or the fact that what little snow we do get is blown off faster), and less-established perennials. Don't give up, and good luck.


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RE: what are the hardiest perennials

Sweetleelee - You gave a great description and details of your growing situation. You certainly have put in a lot of work.
I agree with those that suggested your main problem is the raised beds. If I understood you correctly they are 3 feet high? That is really high and would cause perennials to freeze-out, especially at the edges. Also, tall plants like peonies and delphiniums would be more subject to wind damage in the summer and very hot soil near the bed's edge. .
A couple of other things. As gardeners, we all hate clay. It is a nightmare to work in. But.....clay is a very productive soil. It hold moisture and nutrients far better than any other soil. All gardeners hereabouts have clay and some do not do much to amend it except for the top six inches. Great gardens can be grown in clay!
About your weather. From your descriptions of the temps, it sounds like you are in a zone 5? I suspect you should garden like you are in Zone 3 or 4. The list of plants hardy in Fairbanks applys to zone 1. You can certainly grow a much wider variety of plants in Zone 3.

If you had the time and energy to make a new bed (even a small one) directly at soil level using one of the techniques in the following link...you might having some really good results. It might be worth trying as an experiment?? The link is a discussion on soil preparation from gardeners in Zone 3 and colder that deal with horrible alkaline clay. You may find some of their solutions interesting and worth trying.

Here is a link that might be useful: Soil preparation for perennial beds


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RE: what are the hardiest perennials

Here's a Master gardender group in your area that should be able to give you some first hand information on plants that will do well for you:

Here is a link that might be useful: Glacial Gardeners


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RE: what are the hardiest perennials

Putting bales of straw around the outside of the beds for the winter sounds like a great idea!


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RE: what are the hardiest perennials

I grew up in northwestern Wisconsin (near Superior) where the soil was all red clay. Wonderful perennial gardens can be grown up nort'!

My sister-in-law still lives in northern WI, (I moved south about 200 miles to Zone 4) From your description, I agree with others you are most likely Zone 3.

SIL and I talk gardening a lot. She seems to have problems with her raised beds. Freezing issues. Even though she has mulched on top. I think your bales of straw idea is a great one.

We mulch everything with leaves in the fall. My Clematis get straw and leaves. I've started with roses and they will be heavily mulched even though I've stuck with hardy northern roses.

We also get a thaw freeze cycle here, therein lies why good mulching is so important. I can say I've had excellent luck with day lillies, bleeding heart, sedum, delphenium, cone flower, monarda, iris, peonies, clematis, and now roses. We may be a little warmer here, not by much though. My soil is very sandy, so I've amended it with compost, peat, and aged manure we get from a farmer friend.

As far as pests eating up your garden, have you tried Liquid Fence? I've tried using hair, and the rabbits don't seem to be phased one bit. Liquid Fence has to be reapplied, however, I've had good luck with it. Another relative who has deer problems uses it and has had good success with it.

Good Luck!


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RE: what are the hardiest perennials

I live in the Rocky Mountains, z3, and have had bad luck mixing raised beds and perennials--at least those plants towards the edge die off. The plants a foot or more away from the edge come back every year. Snow in Summer and Sedums are the exeption to this experience. Snow in Summer is great on the edge anyway, as it will drape down over the walls. The straw bales I am sure would work, but what a soggy, heavy mess to move in the spring! You could just plant annuals on the outer edges, perennials on the inside. Also I'd agree that moving back that insulating snow in March may not be a good idea.


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RE: what are the hardiest perennials

Hi, I don't have years of experience in gardening but I suspect that the fact that you uncover your plants in the spring could be a problem because then they are no longer protected from the thaw-freeze cycle.

I also have very poor soil and clay in my garden but I just mix the existing soil with super soil (mix of rich top soil with compost and other nutrients) at about 50/50 in all my beds and my plants are all doing well.

The plants that seem to do best in my garden are peonies, columbines, Hansa rugosa roses (very hardy), daylilies, spirea, european snowball, shasta daisies, hostas, clematis (type 3) and bee balm.

Good luck


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RE: what are the hardiest perennials

Try more natives, would be my suggestion.


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RE: what are the hardiest perennials

Zone 3 or colder perennial list:
Achillea
Ajuga
Allium
Anemone canadensis
Aquilegia
Arctostaphylos
Armeria
Artemisia (some)
Aster
Aurinia
Baptisia
Bergenia
Brunnera
Caltha
Campanula glomerata
" " poscharskyana
" " rotundifolia
Cerastium
Claytonia
Dianthus
Dicentra
Dictamnus
Digitalis
Dryas
Echinacea
Empetrum
Euphorbia corollata
Ferns
Fragaria
Gaultheria
Gypsophila
Helenium
Heliopsis
Hemercallis
Heuchera
Hosta
Iberis
Iris
Lewisia
Liatris
Limonium
Lysimachia
Mertensia
Paeonia
Papaver (Orange)
Phlox
Polemonium
Potentilla
Pulmonaria
Rudbeckia
Scabiosa
Sedum
Sempervivum
Thermopsis
Tiarella
Trollius
Veronicastrum
Viola

This just names a few.


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