For huge hostas and large ones, I never made an hole bigger than 3 feet in diameter and 16 inches deep. After a while, the roots of these large hostas will reach the native soil....and as you know hostas grow in all kinds of soils.

Papou

Papou, thank you SO much! I feel better now, lol! We have clay soil, so I've already mixed peat moss, pine bark conditioner, and mushroom soil into the new bed for my 6 new hostas. Do you think I should plant them a bit above ground (with mulch, of course) for the best drainage? I guess I'm worrying too much but I want them to thrive. :-)

There are differing opinions.

Some say a big hole is neceassary and some say the opposite. The theory of the smaller hole is that the roots get to the native soil faster.

I think as long as you water when necessary, fertilize occassionally, and provide a little TLC 99% of hosta will do just fine.

Goldie,

I've never heard that one. Nor have I ever dug that wide for a tree, let alone a hosta! The widest hole I've ever dug was for Captain Kirk last year (about 2.5' wide) and that was only because the division's root ball was 1' wide. I would plant them at ground level, assuming you've improved the soil to an adequate depth.

The absolutely most important thing in hosta care is LOTS of water, minimally an inch a week. Deeper watering once a week is much better than short watering several times a week. Hosta can take ALOT of neglect but if inadequately watered, they will not thrive.

BTW, GREAT choice of recently acquired hostas!

Char

I have clay soil,Goldie,and I just dig a hole big enough,maybe slightly larger that the potted plant root ball. I've never lost a hosta with this method,so I guess it works! They grow just fine! Phil

AWESOME! I feel SO SO much better now. I'll post a picture once I get them planted. Thanks everyone!!!

Goldie,
You have received good advices from the members. I might add that I would not put mulch too close to the eyes. Stop at the outer edge of the foliage...the "drip line"...otherwise it gives a place in the shade for the slugs to hide under the mulch. A good rule of thumb also is to make your hole twice the size of the pot your hosta is in.

Papou

I say a hole no larger than the root ball; the sooner the roots become involved with the native soil the better. There is much research to support the small hole. I have planted thousands of hosta with the minimum hole method with little or no loss and super results. I can't say I remember losing even one but with nothing is 100%.

The amendments you used are fine for potting media in pots but have no value in the soil. All these amendments came out of pot culture, which is not soil, different in the soil where the plant must use the soil organisms.

See previous discussion about planting and clay, etc. at link below.

http://forums.gardenweb.com/forums/load/hosta/msg0908103322473.html

Now you are looking at the same addition from the south to north.
This is the area that was scraped down to red clay.
I mentioned I planted directly in to a minimal clay hole and
mulched as Ken has mentioned.
They have never received any fertilizer except the organic matter from mulch.

The H.'Blue Angel' on the right is about 6 foot wide;
the reddish tree is Redbud 'Forest Pansy', beautiful deep wine new growth.
The H.'BA' on the left are as big but I don't think they can be seen very well.
The whole area is devoted to blue as a peaceful area.
Note the rock slab bench below the dead cherry tree trunk in the center.

You can see the driveway and the car from the previous picture.

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I sat root balls on top of a limestone driveway and mulched up to the top of the ball and nothing else.

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Thanks so much, everyone!!

I dig a hole big enough for the root ball to fit. Nothing more.