The crown rot is not usually a big deal here in our zone, but when I did get it, it was when I divided too late in the season and planted the divides in too heavy of a soil mixture in the pots, my bad too often until I figured it out.

hh

What soil mixture would you recommend for potted hostas?

There's a great forum here on GardenWeb that is focused on container gardening and there is always a thread going on potting mixes.

Pieter

Here is a link that might be useful: Container Soils

anything in the FAQ's???

IMHO.. in my z5.. crown rot is from one of two things ... [endied up being 4.. lol]

first dividing in heat ... and spreading disease ....

drought causing severe stress leading to reduced vigor in the heat of summer ... allowing disease to take hold ...

and .. yep.. third .. lol ... hyper-fertilization of potted hosta too late in the season in a cold zone ..

and 4th.. planting new mail orders into soil that is too cold ...

when mail ordering.. the plants should have been divided LAST season ... so have no fresh cuts ... and you should have no problems ...

in your zone they should not be planted until at least mid may [or better maybe 6/1] .... so soil temps get warm ....

so if delivery is prior ... you should pot them and protect them from frost/freeze in the garage [especially if leafed out] ... all in one pot is fine ... write the names on the leaves with a sharpie or ballpoint ...

now ... soil is mother earth .. media is what goes in pots ... and dirt is what is all over you and the house after working with either of the above ...

for hosta.. we want an engineered media that holds a lot of water ... so we want it high in peat ... this would be awful for something like trees ... who want high drainage ...

i personally also prefer media that has no fert in it ... your potted hosta.. if they are going to be held over next winter.. need to harden off in fall ... if there is too much fert in the media... soft lush growth.. late in the season.. can result in crown rot the following spring .... i prefer to just add some water soluble when i water thru about august.. and then end the fert'ing ...

crowns should be within an inch or two of the top of the soil [preferably at soil level] .... INSURE that the cone upon which you will place the hosta.. at planting.. is well compacted... so that it WILL NOT SINK .... and you should be all set .... the rest of the back fill can be left soft and fluffy ....

good luck

ken

ps: some mail order houses are in higher/warmer zones ... or use greenhouses .... YOU HAVE TO ASK THEM .... and you have to INSURE that you arent bringing in plants from z8.. and throwing them outdoors in z5 .... they need to be hardened off to temps properly.. perhaps a new post if you want more info in that regard ....

Good info from everyone here, but I would add that I started to soak my hostas in bleach water prior to planting them to decrease the likelihood of pests and diseases. Do a search on bleach here and you will find lots of information.

Dear Deanna,

Crown rot is a very generic description that covers a lot of different issues. There are several diseases that can affect roots or stems leading to rot. Some are soil borne, others can be transmitted by cutting, others from damage from over watering, fertilizer burn, etc. I do all of my dividing in July and August, the hot times when hosta roots are the most active and will heal and recover the quickest.

Personally I wouldn't worry about bare root plants in general. They should be cleaned of any soil - if there is mud or dirt on the roots get rid of it. You don't want to take the chance of any fungus being in the soil.

As for planting depth, the primary reason this can cause a problem is from poor aeration. Hostas like lots of oxygen at the root zone. Planting "too deep" is a misnomer since hostas in properly aerated soil will easily adjust their depth as needed, and in nature the crowns, roots, and dormant eyes are buried. If your soil is kept light and fluffy, and isn't hard, compact, and poorly draining, then the eyes, crown, and roots of a dormant plant should be completely covered (the way they will be in nature). If the plant is already leafed out, however, then you should plant at the previous depth they were growing. Stems will have a protective layer near the base to keep the soil off them, and if you go any deeper you could rot the stems. If the grower made the mistake of planting the crown above the soil, and it is leafed out, then depth changes will need to be done in the fall as they go dormant and the stems will adjust to the proper depth in the spring.

As for potting soil, you also want a coarse, well-draining, well aerated mixture for best growth. If you incorporate dirt or use a heavy, moisture retentive media then there can be problems, especially if you ever over winter them in zone 5. Heavy potting mixes are fine in some parts of the country, but not in the coldest areas. And hostas will get nice thick roots in a coarse mix and spindly roots in a dense mix. Also, those heavy, wet soils will require planting the roots high to prevent problems, due to the lack of aeration. I use a potting soil that has about 60% peat and about 40% pine bark. Water goes right through this mixture, so I really soak them about 3 times a week and let them dry out between watering. The plants develop a thick root system that can fend for themselves better.

You can plant dormant, bare root hostas as soon as the frost is out of the soil and the garden is workable and drains after a rain. You don't want to plant if the soil is wet and sticky at the height of "mud season". If your bare root plants are leafed out early but you are still getting frosts then you will want to pot and protect them before planting permanently outdoors. If I'm getting bare root plants from much warmer zones I always ask to have them sent while dormant, if possible, or I have them hold them until my own plants are leafing out. I'm often planting bare root hostas here in my gardens in southern michigan, not far from Ken, towards the end of April. If I can till the garden and the soil is nice and friable then it is fine to plant.

Well, I'm not sure if that helped much or was more confusing, but hopefully it helped.

Chris

What a great question! It elicited some really good answers!

I have "lost" hostas due to clay soil and excess rain, at least I think that's what it was. I am sure it wasn't voles and such.

I did lose some tiny hosta liner plants which I bought the year I couldn't garden - they were out in the cold, all winter, too much water/freeze. When I finally got to them last spring they were just mush.
Moral of the story being - what you plant them in and where you put the hostas is very important! I have learned a lot from this thread - thank you everyone!

Jakki

great comments chris....

may i presume.. when you are planting in late april in MI... you are receiving fully dormant hosta from mass wholesalers??? .. who have had them refrigerated all winter????

if so .. then you are planting cold plants in cold earth ...

IF you were receiving hosta from greenhouse operations... would you throw them back out into cold soil????

i see you did address leafed out hosta in this regard ... which is why i am presuming yours are fully dormant ...

and keep in mind.. if chris is planting 25 or 50 of one kind.. if he loses one or two.. his success rate is still very high ...

if you order one.. and lose it ... you are at zero ....

err towards being safe.. rather than pushing spring ... is the bottom line ...

ken

PS: it's NEVER the $5 hosta that fails... it will be the most expensive one you order .... in fact.. many of those will commit suicide in the mail or in the car on the way home ...

Thanks for all the good info!

Deanna