It depends on how big a Hosta you buy. The rule of thumb is that Hosta will be 2 to 2 and a 1/2 times larger in diameter than they are in height. Very Large Hosta can be 36 inches high and more than double that at maturity. Maturity however can take 5-6 years. Figure Large plants about 5 ft in diameter and ML about 4 or more. Once a VL plant is mature, you won't be able to move it. So if you are planting a Sum and Substance make sure the placement is right. Smaller plants can be moved as they mature.

Make sure you've defined the drip line at your foundation. Hostas need water and won't do well where it is dry. As for companion plants, in my North facing foundation bed I have Epimedium, Hellebores, Bleeding Heart, Heuchera and several Ferns. The Ferns are nice because they offer a textural contrast with the large Hosta leaves. I use Japanese Painted Fern, Athyrium "Lady in Red" Athryrium "Ghost" and Dryopteris "Brilliance".

Steve

How well does Japanese hakone grass do in zone 5? I repeat it throughout my shade garden and grow a big clump in sun. It works with all colors of hosta, grows and divides well, always looks good, and doesn't require special care. It does take a few years to get established planted from container. It does well in dry shade, as do my hostas, ferns, hellebores, and epimediums. The hakone would look great with the big leaves of your hydrangea.

Carex (sedge) is an alternative for moist shade. I have very little of that so I don't grow it. Astilbe is another classic pairing with hostas and needs a lot of moisture.
They dry up under my trees about mid-summer.

Here is a new transplant of variegated hakone shown to the left of my bench.

what i said in the shrub forum

ken

ya wanna know what ken said in the shrub forum?

what I said in the hosta forum ...