I have a very large hemlock tree and I planted some hostas, some impatiens and 2 rhododendrons under it. Nothing seems to be doing well. I think they need some fertilizer. But someone on another forum suggested that the hemlock tree could be producing some kind of chemical/hormone ect that could prohibit the growth of other plants around it. Kind of like Walnut trees do. The dirt here is kind of powdery and loose I have noticed and I have to water a lot. My rhodies look so unhappy and are slowly turning yellow and losing their leaves. I tried looking it up via a google link, but there was just so much information -some was conflicting and some just pages and pages long. SO does anyone have a hemlock tree that they successfully grow stuff under or near?

I can't find anything suggesting that Canadian Hemlocks are poisonous to other plants, I am thinking they may have confused it with the poisonous hemlock( not a tree but a biennial). Maybe it is just a fertilizer and water problem.
This site is pretty long, but it is mostly pictures, with some good information. You might want to skip over the native plant listing and go further to the bottom to the list of non-native plants that work well under trees.
http://www.extension.umn.edu/g...

The thread "My rhododendron looks unhappy" in Trees and Shrubs forum Here is a link to the thread in the other forum.

Here is a link to what was referred to as allelopathy. I never heard that word before now.

https://www.google.com/?gws_rd...

No specific article mentioned in those links, and the few I glanced at really showed now ill effects on other plants planted under hemlock.

well it seemed to me after reading through some of it that the hemlock produces something that keep other hemlocks from growing in the same area. Hemlock seeds will either not germinate or die if they are within the area of another hemlock, but I didn't see anything specific about it not allowing other kinds of plants to grow. I have never grown rhododendrons before, are they generally pretty hardy or do they die easily? Do they need anything special?

Frillylily
Could this be the problem, the tree is so dense the foliage is blocking out too much sun? Just click on the article text and and that subscription add should go away.
http://www.bhg.com/advice/gard...

Well I don't think that is the problem because the tree is not branched really low, it has been limbed up. I can easily walk under it. I did think rhododendrons like shade though, do they need sun? I just always thought of them as a shade plant along with hostas, ferns and impatiens. It is full shade mostly, a little afternoon sun. But it is light, not a dark shade.

I think all those plants would do well in some shade, but if the tree is only limbed up head high and is fairly large I would check and see just how much sun if any those plants are getting. I limb my trees up as high as my extendable pruning saw will reach, about 15+ feet, and still with all the trees I have lots of shade. Of course I do get some sunny spots and dappled shade spots also. I was noticing the other day one of my hostas (So Sweet) was getting quite a bit of morning sun, and it is doing great.

Some hostas can take quite a bit of sun. My tree has had the top broken out of it about 7 years ago and then it is limbed up about 7-8 ft high underneath. So I can't really limb it up or there wouldn't be anything left. I really don't think the area gets much direct sun at all, just a little in the afternoon when the sun is going down and gets on that side. Will rhododendron live without any direct sun on it? I guess the hostas will? The hostas were all planted this spring and they are all blooming now. Although I haven't noticed much actually growth on them. I know that hostas seem to grow slow sometimes though.

I read that sometimes rhodies can get a fungus that turns them brown. I do have a crabapple in the front yard that looks pitiful and I sprayed it with a fungicide tonight. If that doesn't cure it I am going to dig it out and start over. Here is a pic of my rhododendron.

here are some pics of the area. I think I need to move the rhodies out because they are not getting enough sun I think and maybe they will not be able to compete with the tree roots. I am assuming the hostas are happy because they are at least blooming. Is there anything else that will take full shade, be winter hardy to (-10F) and have some size to it to fill in the gaps?

The rhodies are planted about 3 ft from the trunk of the hemlock. I really did not run into roots much when I planted them. I also read that they like acid soil and will slowly croak with out it, so that could very well be my issue.

The pink Ps are impatiens. The yellow D is a dogwood tree I am going to move somewhere else. the red X are the rhodies and the red R is a Ruby Slippers hydrangea that I think the same thing of about the rhodies. Probably won't do well there long term so I am going to just move it out. There is a sweet gum tree and it is HUGE HUGE. it is also limbed up ALOT so I have this very large sort of hole there. I was wanting to put something kind of sizable there (thats why I put rhodies and hydrangea).
All the rocks, weeds in the foreground are of course not staying there permenant! The black tub is housing some goldfish right now-temporary.
The purple is hostas and the blooms are circled-lots of blooms so I equate that with happiness?
I plant nandinas (red N) around the sweet gum along with some pachasandra because I hope both will be vigorous enough to compete with the gum's roots (very rooty, not a yard friendly tree). If I continue improving the soil and adding mulch, will the hostas do ok with this much shade? They get no direct sun at all really, a little in the afternoon, but that will fade out as the pears (in the next photo) mature.

All junk in background is my neighbors and I hope to put some privacy fence along this in the next couple of years and I already have dappled willow shrubs, purple sand cherry and golden vicary privet planted along the line along with 3 Burford Holly shrubs.



ANY SUGGESTIONS appreciated very much- this area is so shady and rooty I don't know what to do! the dirt if horrible but I am slowly improving on that.
The next photo shows a longer range shot with the red Ps indicating 2 cleveland Pears I planted this spring. These will of course put out a lot of shade in a few years so the area will have even more shade. The area between the hemlock and the pears is mostly sun during the day right now. The area faces north, but the back side of the house is all that gets shade mostly-the first 5or 7 ft out from the house is full shade-no sun. From there out- mostly sun- I want to grow hostas in this eventually-so that is why I put in the pears. The right side of the pictures is west, so lots of hot afternoon sun the pears will block for the hostas.

http://plants.oaklandnursery.c...

Here is a link I found for the rhododendron if anyone is interested. It has some basic requirements/care for the plants. (should have looked this up BEFORE! ha ha -when all else fails-read the instructions....)

Frillylily,

I care for a Hosta garden in a local display garden that is situated underneath 4 large Hemlocks. This year it has done very well, but before I cared for it, it was a mess. Two things seemed to make a difference, lots of water and fertilizer.

The Hemlock roots are everywhere and the suck the moisture and nutrients out of the ground with alarming efficiency. I start with an early fertilizing of Milorganite (5-2-0) when the pips are just coming out of the ground. I throw it all over the bed like chicken feed. Don't skimp on it. It has the added benefit of repelling critters from eating the pips as well. Yes it smells.

This year I repaired the watering system for this garden and it has made all the difference. It's overhead sprinkling, and I water the entire area not just the Hostas. If you just water the Hostas and feed them, the Hemlock roots will go where the nutrients and moisture are and strangle your plants. Make sure you are feeding and watering the entire area so that the trees get what they need as well. I water this garden for about 2 hours a week with overhead sprinkling. Your garden may need more or less depending upon your soil's ability to hold water and the volume or your watering system. You just have to experiment with the amount of supplemental water you provide.

I do another fertilizing in mid-season, around the 4th of July. You can use an organic fert like Blood Meal or Milorganite again. Don't use a slow release. Use something that is available right away. I used some cheap 10-10-10 this year because that is what the display garden had available. It worked well.

This year I had to re-edge the garden two inches larger because the plants were growing into the lawn area. You can grow under Hemlocks, but it takes some care and effort. Below is a pic of the garden I care for.

Good Luck with your gardening.

Steve

Thank you for your thoughts. I love the pic, beautiful garden. (envious of the grass)
I have dug around my hemlock obviously to plant and lay rock ect and really have not gotten into a lot of roots, they seem to be deeper not too near the surface which is why I decided hostas would do well beings they would root more shallowly. But now, just as you say, I am wondering if they are just nutrient depleted because of the tree in general. The soil here is dry powdery and just looks awful. I was afraid to add compost over the area for fear of killing the tree. But now I am thinking I will dig up the hosta and mix the soil with some mositure contril potting soil which I hope will keep it from drying out so quickly. Then I am going to mulch the area more heavily than I now have it, and then I am going to start watering it with manure tea. (the whole area) Lucky for me I only have one tree there not 4, well actually I have 2 because right in this area is also a sweet gum and it has roots like crazy. Some of my hosta started turning brown this past month, but we have had temps in the 90-100 range and no decent rain for a couple months now. Hand watering is just not the same it seems like. I think the hostas were heat stressed and nutrient deficient and probably not rooted well either since I just planted them this spring. So the bed just needs a lot of work all the way around.

How long have they been in that spot?

I've encountered the same issue with several plants - a hemlock (hostas do grow about 5' away), a dwarf Alberta Spruce (two clematises near it died and other plants as well), a Hinoki cypress that also killed two clematises. Now I do not recommend planting any clematises by such plants.

Ticker said:How long have they been in that spot?

@Ticker, I am sorry for some reason I just saw this question The hostas have now been in this spot for 6 years, and have been pretty much dwindling away. I moved some of them out before they actually died all the way- I didn't want to lose them Nothing grows under this tree, not even weeds really and it is a dry dusty mess. Thinking of just mulching it and maybe putting a bench there.