Raising soil level up a trunk

9 years ago

Hi there, I have an established 3m high woody hibiscus in my garden and I'm about to do some landscaping to put terraces in my sloping beds. My question is, if I bring the soil level up by 1m around the trunk (I.e. because I want to leave the hibiscus in place and don't want to transplant or disturb roots) will it still survive? Or is it quite likely to rot? What would you do in this situation?

Sort by:Oldest

Comments (8)

akamainegrower
9 years ago
I would not pile soil around the trunk. Instead, make a 1 meter high ring around the trunk with whatever you're using for the terraces so that there is space around the trunk without soil.
rhizo_1 (North AL) zone 7
9 years ago
It is very likely to rot. It's not recommended that you add more than three INCHES of soil, let alone three feet. That is an extreme form of root disturbance, believe me.

I would plant a new hibiscus in that vicinity after the new soil has settled for about a year or so. By then, the established tree will be in serious decline.

It is not the trunk you should be worried about, but the ROOT SYSYEM. Of course, the trunk will be negatively affected by three feet of soil but if the entire root system is buried, you can kiss your tree bye bye.

Tree well construction needs to be done carefully, with the actual root system in mind, not the trunk! I think that tree wells look funny, odd, out of place, and never encourage their use.

This post was edited by rhizo_1 on Sun, Jan 11, 15 at 6:09
Related Discussions
Level soil or build up in front flower bed?
Q
Comments (3)
Now would be a great time to add some really good soil. Either way, make sure that you've got good positive drainage away from your house. As a landscaper, we usually install the soil so that it's a bit mounded in the center or back, but when it reaches the edging, it should leave room for mulch or rock above it.
...See More
raising soil level - lift up plants or not?
Q
Comments (3)
Kris.....my only comment on Bud's comment about having raised the bed around her peonies and having them bloom....well....I heard once that a flyer bailled out of a plane at 10,000 feet.....without a parachute..... and survived. There is no accounting for just plain dumb luck. The peony is a plant unto itself....it has this brain that tells it...."I'm planted too deep and I will not bloom"..... You put a peony at a particular depth....and it blooms. Then you topdress it....you bring soil around its base, effectively putting the plant deeper. Ninety-nine percent of the time, the plant resents what you've done and refuses to bloom...or blooms not as expected. So, once you have found your depth, leave it there. If you feel your plant is not blooming as you would like, and think its in the ground too deep....simply lift it. Dig around the plant's four sides, as deep as you can so that the entire plant is free of the soil holding it. Then choose the side you wish to lift and put a spade or shovel under...and lift. Backfill as you go. Lift it a half-inch...an inch...but try to not take it out of the ground. Just backfill and firm up....then water generously. Sometimes this will not in any way harm the position of the roots and may not cost any non-blooming time.
...See More
Raising soil level up trunk
Q
Comments (3)
Copying form my response to this exact same question in the Shrubs Forum... The work required to keep the tree alive (a dry tree well) seems like a lot more than the work required to replant. And, even with a dry tree well, it's not a guarantee that it would survive. For me, the ONLY option would be to remove the hibiscus and replant it at its new level. It's just a no-brainer, IMO.
...See More
Planter soil level dropping: how to raise back up?
Q
Comments (1)
..... not sure what you mean when you say "running off to side". An image or two would be helpful. Are the planters resting on the ground and are roots able to enter natural/native soil below the planters? Al
...See More
ken_adrian Adrian MI cold Z5
9 years ago
i think of it this way ...

roots are made to go in the ground and cope with moisture ... trunks are not .... though they may get wet.. they dry rather quickly ... ergo.. as noted.. they rot ..

second.. roots need air as much as soil ... burying them an extra 3 feet deep .... defeats such ...

remove it .... and start with a fresh plant ...

ken
akamainegrower
9 years ago
laurietennant: clearly you want to keep the existing hibiscus, so I think the tree well is worth a try. How it looks is a matter of personal taste. You do need to allow for sufficient space around the trunk. It would also help if the depth you're planning to add were reduced. Do you really need a full meter or would half of that or even less be enough for what you would like to plant in the terraced areas? (That's assuming the terraces will be for plants. If instead this is more a landscaping project with a full meter necessary to do what you want, much changes). A half meter or less over some of the hibiscus roots will not drown them or smother them if you use coarse fast draining material like bark or bark compost mixture with or without grit or sand. Do not use soil. It is too dense and not porous enough to allow oxygen to reach the root zone.
ken_adrian Adrian MI cold Z5
9 years ago
can you give us a latin ID on the plant ...

if we can actually ID the plant.. there may be alternatives ...

are you talking about the common rose of sharon???

where are you???

there is no plant.. that cant be cut back..and lifted to the proper height... and then pruned back into shape .... perhaps we can step out of your box of a 9 foot tall plant ... and offer other options ....

of course.. we dont dig things like this up.. in the middle of the heat of summer .....

ken
brandon7 TN_zone7
9 years ago
The work required to keep the tree alive (a dry tree well) seems like a lot more than the work required to replant. And, even with a dry tree well, it's not a guarantee that it would survive. For me, the ONLY option would be to remove the hibiscus and replant it at its new level. It's just a no-brainer, IMO.
mikebotann
9 years ago
That's just about what I was going to write. The effort digging up the Hibiscus and replanting it is way less work than trying to accommodate it in a new terrace without moving it.
Why do you want to terrace it in the first place?
I do understand that some people like their landscape flat and level and are not comfortable unless it is. Usually no valid reason given.
Mike
User
9 years ago
laurie,
Brandon is right.
Dig it up in spring, or if you can do it now where you live, and replant after the beds are formed.
I have never dug up a hibiscus and replanted one that large, but if you are careful, and mulch well, and water it in good, it should be fine.
Then it will look better too, in the terraced beds, and if it dies, which I doubt, you could always replace it.
Is it a tropical?
Go buy some Great Start by Miracle Grow at any home center store, and use that after replanting.
That stuff is wonderful for replanting all kinds of plants and trees and shrubs.