I'm a he, but that's ok.

How heavy should the mulch be -- the deeper, the better. I'd say at least 6 inches, 12 would be ideal. It should extend out for 2-3 feet in each direction from the plant.

When -- as soon as the frost kills the tops, or at least before you think the soil is likely to freeze more than an inch or two deep.

Cedar, as in cedar mulch you buy for decorative landscape mulch? Well, not really the best choice, because that isn't going to have the right kind of properties. You want something light and fluffly that has a lot of "air pockets" in it. Straw or oak leaves would be the best. If all you can get is some kind of wood chips, better than nothing. One trick I do to help marginally hardy things like agapanthus, alstroemeria, crinum overwinter here is to use a 2 x 2 piece of R12 foamboard or several layers of recycled styrofoam from packing material over each clump under the mulch. Remove this deep mulch layer about the time daffodils bloom in your area.

Cutting down the old stems -- isn't going to make any difference in terms of the plants survival, but generally a good practice, since insects and disease can overwinter in them.

Finally, with dahlias, I wouldn't try this in very heavy soil, especially if water ever sits on the area -- they would be likely to rot from the combination of wet and cold. Sandy, well-drained soil would be the ideal for this particular experiment.

let us know if you wish to know about storing them in the house for winter..

perhaps a new post under that theme ...

may as well cover your bases ... leave some outdoors.. bring some in ...

the little thing you plant now.. will be huge.. and multiply by fall .. there will be enough to do both ...

ken

well, it is a gamble, basically, but one which I am prepared to take, I'm afraid. I can usually expect around half of mine to return (it is not remotely controlled, leaving them outside so even if you mulch or not, it might be a wet year, a late freeze (this year)and so on. But, rooted cuttings cost less than 2 pounds and I am happy to buy a half dozen or so as about a dozen in total and a bunch of zinnias is a nice little cutting bed at my allotment. On the other hand, all that draining and digging and dusting and storing - I always seem to lose a bunch of them too -so, the choice is yours, For me, it is definately guided by depends how mean or lazy I am.

I planted mine in pots last year and then brought the pots into an unheated porch this winter. I totally forgot them - didn't water or anything, and when I went to get the pots for planting this spring, they were not only growing, but had started blooming. I don't know if that will work every year, since this was an especially warm winter, but it sure was easy, and I have no hope of them overwintering outside.

It was not a gamble for me in my zone - all Dahlias that were planted in the garden got rotten no matter how well they were mulched. The soil was well drained for clay. I agree with Denninmi, you would need a combination of sandy soil and heavy mulching for Dahlias to survive.

The only Dahlia that returns for me reliably is the one that is planted 2' from the house foundation. This is my zone stretcher - I grow Calla Lilies, tender purple Oxalis, and Dahlias there without digging them up for winter.

On the other hand, Dahlias are easy to dig and save for the next season. There are lots of excellent instructions on Dahlia forum. They are also quite cheap compared to other plants, so I buy a couple of new ones every year.

To the OP, just remember, it is an an experiment. And, what works for one or two or three years might not work when a particularly harsh winter comes along, so only trial with plants that you wouldn't mind losing if push came to shove.

Thanks everyone. I am definitely going to try overwintering with added mulch. There is a nearby stable (actually two different stables are in my town), so hopefully I can obtain straw from there.

Question - does straw ever contain weed seeds? I'd hate to introduce additional weeds.

As far as digging them up and storing them, my big problem with that approach is I hate digging in the cold. I consider 50 degrees chilly, so actual winter temps are nothing I want to do outside work in.

Hay is cut meadow grasses and often has weed seeds. Straw is generally pretty pure and doesn't have many weed seeds, if any, but usually has a few seeds of whatever cereal grain crop it came from, generally either wheat or oats, rarely barley or rye. Those will sprout, but are very easy to pull. If you get oat straw, the seedlings will die in the winter in all but the mildest parts of the U.S.

Thanks for the info regarding straw. I already have a nice variety of weeds, definitely don't need more.

If this works, it will be fantastic. The less digging I need to do, the happier I am.

Oh, and denninmi, sorry about the unintentional sex change!

mmm, I thought Deninmi was a woman too - I have actually been reading it as 'denim mini' so yep, quite a clear (and totally erroneous, I hope)image has been floating in my brain.

Well, I'm on the border of 5/6. here is how I do it. After a hard frost, cut down the tops and clean up good. I use heavy duty foil to cap off the tops. This keeps moisture out of the stems that are hollow and saves them from getting moisture in and rotting. I pile grass clippings over the top for a good thick mulch. They all lived last year. I dig them every other year, if you don't, the clump will get so heavy you won't be able to lift it.

you get your straw.. near halloween.. when it is stocked for fall garden displays .. you know.. the bale.. the pumkins.. the cornucopia ... and when the cold weather hits.. use the display .. to cover the garden ... in fact.. i have been known to garbage pick some bales. in early nov ... free for the taking at the curb ...

when they harvest the crop.. the big john deere cuts off the top .. with the seed.. and makes money ...

the 'second cutting' ... is the straw ... which in theory.. has no seed ... it is nearly literally .. a hollow stalk .. aka straw ... adn man.. these things will cut you.. long sleeves and jeans and leather gloves .... when tossing it around

the third product.. is an animal food.. forage ??? ... which these days are usually those huge rolls ... which includes the whole plant.. like the cow or horse.. might eat out in the pasture ... usually with a high percent of alfalfa.. though for the small time operator.. still sold in convenient bales ...

the cheapest of them all is straw.. aka bedding stuff.. it has little inherent value.. as to its food value..

wow.. i know way to much about this.. for a city boy.. lol ..

BTW.. this is one of those trick questions.. where you can really delineate the knowledge base of you nurseryman or garden friends.. if the guy selling it .... doesnt have a clue what you are talking about.. that should tell you something ... like.. questioning EVERYTHING else.. he spreads around as manure.. lol ..

i always ... thought denn was IN MI... so i always thought he was a guy .. but then he said something girlie.. in some post.. and then i got really confused.. lol .. try to man up dude.. lol .. and no.. i dont remember the specifics ... lol

ken

Getting straw from Halloween displays is a great idea, Ken. I'll keep my eyes open in October to see who's doing the whole fall celebration theme.