So you are going to "quarter" each pot? How big are the pots? Actually hostas never "need" to be divided. They just get bigger and wonderfuller...I like that new word. It really does depend on the hosta. Some require more room than others. Whatchu got? If you want your Sagae to get over 7 feet wide, or your Pandora's Box to get up to 1 ft. wide, it will all depend on whatchu got?

-Babka

Thanks for your response. I knew someone was going to ask that as soon as I hit 'submit'. I thought I would quarter each pot so that I get some fairly rapid growth in the spring. As far as I can figure out I have Wide Brim, Francee and two other unidentifiable types (one may be Patriot). They are true survivors having lived through several years of outright neglect. They just keep coming back every spring. I would think that once they are out of their 16 inch pots, receive some well-deserved attention and have room to grow, that they will spread. I thought about adding a couple more varieties but perhaps I should pay penance to the existing plants by taking care of them properly before adding new ones.

francee is easily a 4 foot wide plant..

so you box should be 4 feet wide.. min ...

ken

Also agree to Ken's suggestion of planter of 4 ft wide and bordering a shed or garage, Make sure you plant them inside the water drip for when it rains or the force from the roof will wash all your soil away from the roots. Yes, I did it and had to move 20 different hosta back closer to the shed. If you are on the ridge side you are okay.
Faye

I agree with Faye and Ken. I think the reason 4 feet is often used in 'raised beds' is because it gives easy access from both sides. In your case the 20' length will certainly have it classify as a planter. Since it will be against your garage then there will be access from one side only (unless it is grounded and may be set away some) I might consider 3' as more practical for access or aesthetics.

Nothing wrong with a raised bed either. 20 ft of timbers PT or RR ties) might fit a 'rustic' style or you may have a more formal idea in mind.

Lay out some boards, scratch the outline in the ground or In some way look at what seems to be the proportion you like at the depth you intend to use. Four feet will be the optimum for capacity, but may overwhelm the area, or not if it is a large area.

My two cents.

Jon

of course.. you could just get rid of the OLD monster francee ...

and collect smaller hosta ...

rather than trying to bonsai a monster into a small plant every few years ...

if it dont fit.. get rid of it ..

ken