Christy, the biggest problem you'll have is a lack of moisture. The cedar's canopy will keep the hostas rather dry, I should know, I have a cedar with some peonies under it and I invariably have to supplement their water needs late spring and summer., the canopy gets too dense. Now, a pine's a different story, I have a pine with a sizable stand of hostas under it, and they thrive. Without supplemental watering.

Pieter

Hi Christy: I never researched what the Eastern Red Cedar does to protect itself from competition. I do know that their rooting habit is much like maples. But I suspect added to this is a similar habit to Black Walnut, but it isn't juglone. Everything under the cedar gets coated eventually with a goey, gritty mess of sap which I suspect will coat wide leaves and prevent gasses from passing back and forth from leaf to air. When I say gritty I think it ia blowing dirt which will seal the leaf off from the sun too. If that is the case then a raised bed isn't an answer. I even avoided placing a potted plant overnight under a cedar.

This coating, during the warm seasons doesn't take long to develop either. And if you have an old cedar you know how hard the sap is to remove from your hands and clothes. If you know a secret about THAT please share, although since moving from cedar-heavy northern Arkansas to IL I no longer have cedars. (Yay!) I have had to throw away plastic yard furniture because it quickly got coated. It seems the sappy mess also is a good media for mold development also.

All I know is what I have experienced with cedars. They are lovely looking trees - from far, far away IMO. If I only could pick 2 things to avoid while living in Arkansas one is the Eastern Red Cedar and the 2nd is "don't put Magnolia leaves in your burning pile".

Les

give it a go ..

but you already said the roots are as bad as maple... so do not expect much long term success ..

and understand.. adding fresh soil above.. is not going to stop the tree from filling that fresh soil.. with fresh roots ... been there .... done that.. trees ALWAYS win ...

the hosta will not die fast.. so if and when you note decline.. just move them.. it may take a few years

ken

You could try lining planting holes w/ newspaper as suggested by Ken Druse in his book Making the Most of Shade. His reasoning is that the new plants can form roots without tree root competition to get established before the newspaper decomposes.

He also says to bury plants in pots inbetween the tree roots because it's easier to divide later & protects the roots.

You'd need big pots for hosta & have a watering plan. He didn't specifically address hosta needs.

I have other plants under a western red cedar tree & try to grow what does okay in dry shade there except for near edges where I can reach to water occasionally during our dry summer. We have plenty of rain the other times of the year for the plants. Skimmia would like more water because it gets spider mites in the dry shade. I have watered it more this year, but it's not going to be happy unless I MOVE it. Might be the same for HOSTA --

--not happy unless growing away from a large cedar tree.

It is raining right now, but when it stops, I will take a pic so you can see what kind of cedar it is.
It does not seem to have much sap at all, I do not know if it is because of its type or not.
I have actually had large potted above ground hostas under this tree for several years. They do not even get winter protection, and they have survived with no loses. But I have always had not too special types there. If I make the bed, I want to put some nice ones there.
Like I said, they would be in their own large pots in the ground, so I think it would be hard for the tree roots to disturb the hostas.
Since it is a raised bed, I was also going to lay down that black garden cloth (forget the real name of it) for added protection from root intrusion. So between them being in pots and the cloth under the bed, I think it should be ok.
I am just at a loss for shade now and have many homeless hostas. And my addiction will not allow me to stop buying so I am desparate to find more shaded places! LOL!
I live on a lake, and where it is not bulk-headed, is nice shade with trees that go up to the water line. I would LOVE to put hostas all through there,it would look so natural and beautiful. However, the ground there is too rocky and hard to dig through because of the waterline. So I cannot even really dig down enough to put pots in the ground.
I could just put them in pots above ground and have them like that, but when it comes winter, I do not know how they would handle being in pots above ground.
However, I have many hostas in pots that stay above ground all year long, and come back every year. Out of all of these years, I think I have only lost 1 or 2 in pots above ground. SO it probably can work.

I have lost so much shade over the years here. Not only to storms, but for some reason, when trees here get to a certain age, they start to rot from the middle out, I assume because they are taking in too much water from the lake. I learned this the hard way when a 75 foot pine fell out of nowhere! It missed the house by a foot!
I also just recently had to cut a nice huge Oak for the same reason. It was actually leaning towards the house, and the middle was rotting. Lost 3 oaks that way.
Well, enough rambling. I will take pics when it stops raining so you can see the cedar. Thanks!

Yes, knowing the type of "cedar" is important. Common names can be misleading. Although Eastern Red Cedar is quite common, your zone could also grow Eastern White Cedar (not a true cedar) as well. Although conifers' allelopathic effects can influence plant size, many conifers might only affect germination of seeds near them or nothing at all. Still others might affect some plants and not others. One study showed Eastern Red Cedar affecting the size of corn while having no affect on peas, for example.

tj