How deep should you plant a hosta?
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- Chris_W
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How deep should you plant a hosta?
How deep should you plant a hosta? What are the consequences of too shallow? Too deep? What is the "right" depth for a hosta?
Plants that are too shallow get heat stress faster, drought stress faster, and can get cold damage over the winter if that crown gets exposed. Deeper plants tend to stay dormant longer which can be important with frost sensitive plants like the fragrant ones. If you have hostas coming back smaller with smaller leaves, check if you can see the crown. If so it is too shallow.
Plants that are too deep will need to grow up closer to the surface. Eyes may emerge further out from where the main clump was located so that you no longer have a tight clump. Stems may rot a little easier if they get buried in summer by mulch.
I always try to get the "right" depth, but I would much rather err on the side of planting a little too deep. Plants will establish the "correct" depth the very next season if they were too deep. For example if you plant a crown at 3" and it wanted to be 2" you will probably never even notice that it had to grow up that extra inch below the surface before producing a new eye. However, plants can take several seasons to grow deeper if they come back at all when planted too shallow.
In our rows we will often find that the largest hostas are the ones that were planted a little deeper than the rest. TOO deeply and we will see that the eyes are spaced a little further apart but are still usually the largest plantlets. When we have a plant that is struggling we find that the crown is often right at or slightly below the surface. We also find that moles often tunnel underneath plants causing them to rise up closer to the surface, plus creating an air pocket under the plant. Those plants dry out in the summer and struggle over the winter.
The only time that depth may pose a problem is if they were buried or sank during the season. If a hosta was growing at a depth of 1" from the top of the eyes/dormant buds to the surface and was then planted at a depth of 3" you might get some stem rot. By early to mid summer most stems are hardened off to the soil and can tolerate a little covering but you might get rot problems during the heat of the summer. Because of this we prefer to topdress shallow hostas in the fall after they are starting to go dormant. In most cases it is just better to get the depth close when planting and the hosta will find its way the next spring if you were off a little.
Two examples of plants finding the right depth after being planted too deep:
1) A Hosta 'Riptide', one eye, was planted last summer with the crown at a depth of 3 1/2". This particular eye emerged last, but by mid summer the eye was slightly larger than other plants around it. I dug it up and it had grown an elongated stem out of the main eye and then established a new crown at a depth of 2", measured from the top of the dormant buds to the soil level. Roots were at about 2 1/4". Our remaining plants were only at a depth of about 1" but should have been planted up to 2" deep without causing any harm.
2) A Hosta 'Pineapple Juice' was noticed in the growing area with 6 eyes spaced very far apart. It was planted last fall. Upon digging it I noticed that it had been planted too deeply, and possibly at an angle. The deepest eye from last fall was at a depth of 4 1/2". The shallowest was at a depth of 1 1/2". All of the eyes produced elongated stems and every single one produced a new eye at a depth of 1 1/4" with roots around 1 1/2". So in this case the proper depth would have been about 1 1/4".
Here are pictures of the Pineapple Juice. It was 2 eyes planted last fall when dormant:
And here is a picture of what it looks like below the surface. Note the elongated stems that emerged from last year's dormant buds. Those stems grow up to the correct depth for this hosta and then develop new crowns.
Another picture of the side of the crown that was a little shallower, but still too deep.
Because this hosta had developed all new, separate, well rooted eyes I went ahead and divided off all the stems. I got 6 individual plants:
And finally, here is the leftover crown from last year after the divisions were taken off. There are a couple tiny dormant buds still on this crown. I replanted the crown at a depth of 1 1/4" to the top and it will probably grow a couple tiny babies next year:
After observing many plants I have discovered that every hosta wants to grow at a slightly different depth. Riptide was 2". Pinepple Juice was 1 1/4". And I've noticed on Kiwi Hippo, a giant hosta, that it did not develop any elongated stems even when eyes were 4" deep. It seems that the larger the plant and the larger the eyes the deeper they want to be. In all cases the dormant buds prefer to be completely buried.
I'm using this rule of thumb when planting new plants, based on the overall, mature plant size approximation. It may be closer related to mature eye size. The larger the eye the deeper the crown wants to be:
Mini - I plant about 1/2" deep (soil to top of buds)
Small - about 1/2 to 1" deep
Medium - about 1" to 1 1/2" deep
Large - about 1 1/2" to 2" deep
Giant - 2" to 3" deep
My advice: If you can see the dormant buds at the surface in the fall consider topdressing the crowns with organic matter so that they are better protected. An extra 1/2" of compost or an inch of shredded leaves could make a big difference in how well they come back the next year.
I hope that is helpful to see what happens when a hosta is planted "too" deep.
Plants that are too shallow get heat stress faster, drought stress faster, and can get cold damage over the winter if that crown gets exposed. Deeper plants tend to stay dormant longer which can be important with frost sensitive plants like the fragrant ones. If you have hostas coming back smaller with smaller leaves, check if you can see the crown. If so it is too shallow.
Plants that are too deep will need to grow up closer to the surface. Eyes may emerge further out from where the main clump was located so that you no longer have a tight clump. Stems may rot a little easier if they get buried in summer by mulch.
I always try to get the "right" depth, but I would much rather err on the side of planting a little too deep. Plants will establish the "correct" depth the very next season if they were too deep. For example if you plant a crown at 3" and it wanted to be 2" you will probably never even notice that it had to grow up that extra inch below the surface before producing a new eye. However, plants can take several seasons to grow deeper if they come back at all when planted too shallow.
In our rows we will often find that the largest hostas are the ones that were planted a little deeper than the rest. TOO deeply and we will see that the eyes are spaced a little further apart but are still usually the largest plantlets. When we have a plant that is struggling we find that the crown is often right at or slightly below the surface. We also find that moles often tunnel underneath plants causing them to rise up closer to the surface, plus creating an air pocket under the plant. Those plants dry out in the summer and struggle over the winter.
The only time that depth may pose a problem is if they were buried or sank during the season. If a hosta was growing at a depth of 1" from the top of the eyes/dormant buds to the surface and was then planted at a depth of 3" you might get some stem rot. By early to mid summer most stems are hardened off to the soil and can tolerate a little covering but you might get rot problems during the heat of the summer. Because of this we prefer to topdress shallow hostas in the fall after they are starting to go dormant. In most cases it is just better to get the depth close when planting and the hosta will find its way the next spring if you were off a little.
Two examples of plants finding the right depth after being planted too deep:
1) A Hosta 'Riptide', one eye, was planted last summer with the crown at a depth of 3 1/2". This particular eye emerged last, but by mid summer the eye was slightly larger than other plants around it. I dug it up and it had grown an elongated stem out of the main eye and then established a new crown at a depth of 2", measured from the top of the dormant buds to the soil level. Roots were at about 2 1/4". Our remaining plants were only at a depth of about 1" but should have been planted up to 2" deep without causing any harm.
2) A Hosta 'Pineapple Juice' was noticed in the growing area with 6 eyes spaced very far apart. It was planted last fall. Upon digging it I noticed that it had been planted too deeply, and possibly at an angle. The deepest eye from last fall was at a depth of 4 1/2". The shallowest was at a depth of 1 1/2". All of the eyes produced elongated stems and every single one produced a new eye at a depth of 1 1/4" with roots around 1 1/2". So in this case the proper depth would have been about 1 1/4".
Here are pictures of the Pineapple Juice. It was 2 eyes planted last fall when dormant:
And here is a picture of what it looks like below the surface. Note the elongated stems that emerged from last year's dormant buds. Those stems grow up to the correct depth for this hosta and then develop new crowns.
Another picture of the side of the crown that was a little shallower, but still too deep.
Because this hosta had developed all new, separate, well rooted eyes I went ahead and divided off all the stems. I got 6 individual plants:
And finally, here is the leftover crown from last year after the divisions were taken off. There are a couple tiny dormant buds still on this crown. I replanted the crown at a depth of 1 1/4" to the top and it will probably grow a couple tiny babies next year:
After observing many plants I have discovered that every hosta wants to grow at a slightly different depth. Riptide was 2". Pinepple Juice was 1 1/4". And I've noticed on Kiwi Hippo, a giant hosta, that it did not develop any elongated stems even when eyes were 4" deep. It seems that the larger the plant and the larger the eyes the deeper they want to be. In all cases the dormant buds prefer to be completely buried.
I'm using this rule of thumb when planting new plants, based on the overall, mature plant size approximation. It may be closer related to mature eye size. The larger the eye the deeper the crown wants to be:
Mini - I plant about 1/2" deep (soil to top of buds)
Small - about 1/2 to 1" deep
Medium - about 1" to 1 1/2" deep
Large - about 1 1/2" to 2" deep
Giant - 2" to 3" deep
My advice: If you can see the dormant buds at the surface in the fall consider topdressing the crowns with organic matter so that they are better protected. An extra 1/2" of compost or an inch of shredded leaves could make a big difference in how well they come back the next year.
I hope that is helpful to see what happens when a hosta is planted "too" deep.
Last edited by Chris_W on Aug 05, 2005 9:54 am, edited 1 time in total.
Very good essay, Chris, and I agree with you on the planting depths also. Problem childs have always been the ones that got planted shallow, in haste, or heaved themselves up after a few years because they had no more room to grow down, either because of tree roots or rock. In my case, most of the time its easier to top dress late fall than to dig and replant deeper. Good info.
Thanks so much, Chris! Very well written and illustrated. Ever consider a book? I was starting to wonder if I'd been doing it wrong these many years, what with all the advice going around to plant hosta crowns at the soil level like iris. Thanks for the reinforcement.
jd in nh
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- Gardentoad
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Nice article.
Thanks.
Thanks.
Last edited by Gardentoad on Aug 04, 2005 7:48 pm, edited 1 time in total.
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- scootersbear
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I second Janet's suggestion...why don't you write a book...or at least compile some of the great information from the forums and archives. There is great seed starting information, perhaps the best HVX information on the web, great plant care such as the above...and the best hosta photos on the web from the actual growers. It seems to me there's a book already written on your server!
Very informative, thanks Chris
Do the type of soil have any influence ?
Pia
Do the type of soil have any influence ?
Pia
Against stupidity the gods themselves struggle in vain.
E-mail for pics hostapics@gmail.com
E-mail for pics hostapics@gmail.com
Chris..I am wondering right now if I have planted too shallow many times. That was a wonderful presentation and a huge helping of food for thought.......!
It makes sense, and sometimes I get plants with several baby eyes budding up, close to the division I am planting, then I wonder....if I put them near the top, they'll get more sun and "spring to life" sooner, but in reality, they probably were totally in the soil prior to division, and it would be better in the long run to bury the main eye a bit deeper.
Oh--and answer Pia's question. Sorry!
It makes sense, and sometimes I get plants with several baby eyes budding up, close to the division I am planting, then I wonder....if I put them near the top, they'll get more sun and "spring to life" sooner, but in reality, they probably were totally in the soil prior to division, and it would be better in the long run to bury the main eye a bit deeper.
Oh--and answer Pia's question. Sorry!
- Chris_W
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Not that I know of. I've seen this occur in potting soil, sandy soil, and heavy soil like we have here.thy wrote: Do the type of soil have any influence ?
One thing I saw, however, was that a thick, loose covering a leaves did not cause the hosta to grow out of the ground into the leaves. In this case the hosta had longer than normal petioles. Somehow the plants know the difference between soil and leaves.
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Dear Chris,
Very good information. Thanks!
Danny
Very good information. Thanks!
Danny
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- Frodo the Hobbit
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Brilliant, Chris!
I created a new lasagna garden a couple years ago, adding a lot of organic matter which settled to almost a foot deep. There were some (left-over bits of) ventricosa and undulata on that spot, and they eventually worked their way to the top. From that, it appears that if 'too' deep, they pull themselves up to the preferred depth.
I think from your article above, some of my other hostas need to be less shallowly planted... might be just the information to get some of them growing better. Thanks!
I created a new lasagna garden a couple years ago, adding a lot of organic matter which settled to almost a foot deep. There were some (left-over bits of) ventricosa and undulata on that spot, and they eventually worked their way to the top. From that, it appears that if 'too' deep, they pull themselves up to the preferred depth.
I think from your article above, some of my other hostas need to be less shallowly planted... might be just the information to get some of them growing better. Thanks!
O.K. I agreed right? but now, can you come up with a reason why a hosta that has been dug up and left sitting on the ground, unplanted, doesn't die over the winter? I swear I've never lost one overwintered this way, whether its in a big root ball of earth or bare roots...tossed under a tree/shrub or in the middle of the lawn? I've trying to figure this one out!