You did the tree no favors. The majority of tree roots are in the top 18 inches of soil. How big is the tree and how much around the tree did you dig? I can't speak to spruce, but I have plenty of hosta under pines without issue.

tj

I dug a third around the tree. I dug out to the drip line. The tree may be 30-35' tall. I wonder how deep the tree's major root system is. Most of the roots are less the a inch in diameter. I did cut a larger one which was 3-4" in diameter. I asked the question because I have heard that planting under a maple tree is not a good plan. The soil under the Blue Spruce does become quit dry in the summer (I live in southwest Iowa). I don't mind watering the hostas occasional during a dry spell but watering the hostas and having the tree rob all the water sounds hopeless.

Cutting those roots may inadvertantly kill or hurt the tree. Those lateral surface roots help the tree get its daily drink... Even if it is only morning dew it sucks in. They will likely grow back, if it doesn't go through an extreme drought and begin to decline.

Those roots also help anchor the tree. I replaced a few spruces atop a sandy berm on a golf course. They just toppled over like giant bowling pins in the extreme wind. After much discussion about how I would place the new ones.... I agreed I would do whatever they wanted but I would not give them a 1 year guarantee on the trees if I did. The new spruces did not go back in the berm :)

Everyone wants to plant under spruces. I know better and still do... But its more of a temporary holding place for me. There is no David and Goliath story here. 35' spruce vs. Itty bitty hosta? My money is on the spruce. It will suck up every drop of water in the air ... Andnthe hosta may put up a good fight for awhile... But will suffer for it, eventually

I plant under bigger White Pine (75 feet or more) all the time and it seems that the hosta have no problem going deep under the pine roots and the trees don't suffer any damage or even slowing of growth. I do agree excessive planting, enough to affect much of the shallow root system will kill the tree. My guess is that if you keep damage to 10% or less of the root system there would be no problem. Digging 30% around the tree is very dangerous and may be fatal.

Jon

Most white/red pine trees have a deep tap root in addition to lateral runners... unlike spruce that depend on a shallow lateral root system. Spruce will suck more moisture and nutrients from the surface, as it is their primary source. When moving pine, I have cut that tap root and seen root structures on both.

I have a hosta bed under a huge blue spruce, started it about three years ago. I might be lucky but didn't encounter any major problems with roots. My hosta, Heuchera, daylilies etc are doing well. It is definitely drier under this spruce. I added soaker hoses about a month ago. we have had a ton of rain since then so I only used them once, they did a great job and are more effective than hand watering. Don't let anyone tell you you can't garden under a blue spruce, I am doing it.

Sherry

No one said you cant... just why you shouldnt. Offering my knowledge of tree systems so an educated decision is made.

Not saying stuff won't live... just no better than grass would as it tends to be sparse under spruce with reason. Soaker hoses will bring the roots to your plants. If your hosta are 3 years in, I would politely say you may proved my point.

Depends smorz, here are some examples of hosta with White Pines in my yard.

3 White Pines surrounding planted hosta. The outside ring (Minutemen) is a couple of years old and each is about 2 feet across.

Same area, big oak in front and another big pine in back. The size of the hosta in the ring is equal all around with distance to the pines not seeming to matter.

Big pine in front and Pig Nut Hickory. The smaller Elegans near the pine is at least 5 years newer, so no direct comparison of the two. Hickory is in the walnut family which is excellent to plant hosta under.

Dream Queen on left, Twilight to the right and Sum and Substance thriving behind (2nd year). There is also an Empress Wu doing well behind this twin pine combo which is at least a 24 inch caliper each.

Based on my experience I would not say you should not, but only that it might not be a good location and trying one or two as a test would be advised rather than planting an expansive bed that might not work out well and be a costly experience in money and effort.

PS- I never fertilize and water in very dry times only. The soil is very rocky and sandy.

Jon

You must not have seen my post that pines do have a different root system then spruce Jon? I said shouldn't under spruce... Spruce! geesh guys! Lolz :)

Thanks for the comments guys.

Randy

Just an added note, my hosta were VERY small when I planted under my spruce, most were added last season. To me this beats sparse grass or just mulch.

Sherry

Rooting Habit- Young seedlings of blue spruce are shallow rooted, with roots penetrating the soil only about 6.4 cm. (2.5 in) during the first year (50). Although blue spruce tissue is not damaged much by freezing, seedling losses can result from frost heaving. Shade in late spring and early fall minimizes such frost-heaving losses (2,69).

Even in mature trees, the root system of blue spruce is relatively shallow, compared to that of Douglas-fir and ponderosa pine, adapting it to the moist site on which it usually grows. In spite of the shallow root system, blue spruce is decidedly windfirm.

US Forest Srvices opinion

Ok Jon?... that thick shallow root mass (I have held in my hands) leaves no space for plants to flourish. That was my point, thanks :)

But (on a side note) nothing is truly wind firm in sand or loose soil... and is therefore subjected to frost heave as well. Even with the mature trees. If not, especially with mature trees. We are prone to sheer winds here... not everyone is.

I was giving my opinion based on what I have actually seen/experienced not googled... in attempt to be helpful Jon :) Have a great weekend !

...and likewise.

Jon

Spruce bad. No grow under Spruce.

Envious of your space but that looks just wonderful - all of it!

Thanks, Jo, that's very nice of you to say. With more experience under my belt, there are many things I would do differently on our 1 1/3 acres. Lots of space to expand but the difficult part would be maintaining it all. Lots of things to tweak and improve still. Some hostas seem to grow bigger than you expect, others not enough. Have to find a new spot for Patriot. He wasn't growing enough where he was but now he's outgrown his new spot.What I wish I'd done in the beginning is used more giants because they take so long to develop.

I've also encountered some surprising growth that has left me almost speechless! Where am I going to move some to??? I don't mind them touching at all, but some are literally rubbing shoulders, not just elbows. And some are downright bullies! Striptease has leaped and covering 3 hostas. Lol

Ann Kulpa had a leap year too...large, beautiful leaves squished between S&S and QOTS. Colour wise... She needs to go elsewhere. Love the biggies but have no room. So what do I do? Buy Squash Casserole, for one, ....and we know she is not a shrinking violet! Jujen, although smaller than mama is not tiny either...and on and on it goes.

I don't know who has the bigger problem, you or me. You are looking for fillers you said earlier in a post...I'm looking for space! Lol I've decided I'd just rather have your problem, Irawon. I remember my huge house when the kids were small - it was a breeze to clean, everything was so spaced out, it was great! Gardening is like that too, at least to me...the more room, the more "stuff" to be sure...but it's heaven, keeps one active, and the aches and pains go away with some rest. I get lazier I admit but I do love playing in the dirt, talking to toads, birds, swearing at bad bugs...all in a day's work, right? well, we don't all cuss..... ;-)

So I transplanted hostas from under white pine to under the outer rim of my 70ft Blue Sprice... Although they grow...some other varieties not so much... Going to dig slow-pokes, enrich soil and add peet.. and re-plant... watering helps... Soil pbviously high in pine acids so enriching soil should help...