Can I till this close to tree?

Hello! I'm not sure if this is the right board to post my question, but I didn't get much response in Garden Design. I have this problem area I need to work on this fall. I've been unable to get anything to thrive here, so I'm pretty sure I need to just amend the soil. It doens't have much clay, but the soil seems very hard. Consequently the little amount of rain we get doesn't even soak in. I'm thinking of putting some heuchera or ajuga in this area. But my main concern is tilling the area because it's around a fringe tree. I'm worried about hurting the roots. I don't plan on planting anything right up against the tree trunk of course, but starting about 4-5 feet from the trunk, all the way to the grass. Does anyone know how I should go about amending the soil in this area? Please, not by hand! Thanks for any help!

I wouldn't till very deeply and I wouldn't go closer to the trunk than the outer edge of the canopy of the tree. That is why I suggested to you to plant something like lirope where you can just stick in little plugs to fill the space - no significant digging and no tilling. Maybe with the ajuga or the hechura you can find just very tiny plant starts and just amend the hole to plant.

Hmmmm... Well, the tree canopy covers just about the whole area, so I guess tilling is probaby out of the question. I remember your liriope idea, but I guess I've just never been a huge fan of the stuff. But I will have to consider it since there's not alot that will work in this soil. I guess even if I just amend the individual holes, and buy some ajuga or something, once the plants start spreading, they will eventually run into un-amended soil. There's a pretty nice variegated mondo grass that was kinda nice, so I'll look into that. Maybe it would be okay there. Thanks for the help!

90% of feeder roots are in the top foot of soil, and most of those in the top 6 inches, so the less cultivation you do, the better. Feeder roots on a maturing tree extend far beyond the canopy.

DP agree about the feeder roots extending far beyond the canopy ---but I figured if she could just stick to what was beyond the canopy it would be similiar to root pruning and not too adversely impact the tree.. new feeder roots would grow from the point of impact and back.

Erdooley - not a fan of lirope either. (But I do like that short mondo --- but it is $$) I wouldn't worry so much about the ajuga running into soil not amended. Just give it a good start in the small hole you make --- really pulverize that soil in there and it will take care of itself...as it rains and the ground softens, etc., it will make its own way. I would not start with a large plant ..just a small one ....and small hole for you to deal in that difficult place. Also, there is something to be said for not amending the ground---but rather give the plant the same conditions it will have to deal with as it spreads. otherwise it may just stick to the hole and become root bound!

You may want to check out High Country Gardens..they have a good assortment of low growing ground covers and will give you all the info you need about growing conditions so you can find one that will do well under the tree. I am not suggesting you purchase .... I would look locally etc., but if you do decide to purchase, I have found that the plants I receive do well and if not, replacement or refund is prompt (unless it is out of season, then you will get it as soon as the planting time is right).

erdooley--High Country Gardens is great but just look at the info on all the plants very carefully. They specialize in plants for arid country (out west). I'm sure GA has lots of humid weather like we do here in MS and lots of their plants can't handle that. I've ordered a few plants from them that are doing great here though. They do pack their plants real well and have an excellent return policy.

Yes, and they do a good job of telling you what should be grown out west (via symbols) and what does well in other areas --leaves out the guess work for you.

Go ahead an turn the whole area over with a shovel. labor intensive yes, but you'll be surprised how quickly it goes by. Don't worry about a mature trees roots in that area, the amount of root to the zone you need is nothing. Don't over complicate this, go to lowes and get 15-20 bags of soil conditioner, thats the name and it's $2.79 a bag. Throw it on top of the turm=ned soil, don't worry about breaking it into fine pieces (your soil) then give it a quick turn again. Plant whatever you can get in the ground, I like your idea get as close to the trunk as you can and plant out. Your not going to hurt the tree. Then mulch with the soil conditiopner, it's small pieces of pine, looks great and breaks down into the soil and adds organic matter to the soil to loosen it up. Next year take a soil sample and see where the ph stands and go from there.

kitten0115- I wonder how many people understood this part of your advice: "The amount of root to the zone you need is nothing." You advise not complicating this, but adding amendments close to the trunk of a tree is inviting suffocation of the roots at the root flare.

well, actually you sholel are close to the trunk as you can which is close to 2-3 ft away from the base because of all thick roots. Sorry ididn't mention not to cover the flare of the trunk. You would have to add a bit to suffocate the roots. Soil built up to high on the trunk doesn't suffocate roots because the feeder roots of a mature tree are away from the base, the larger ones near the trunk don't do the main fed of the tree. The problem with the soil is that you invite the trunk to stay wet and open it up to insects and disease. This is not a complicated process at all. Dig up the soil as close to the tree as possible, even the soil near the flare can be ammended and help with the overall heath of the tree. You don't have to stay clear of that area, as the soil compacts the soil level will decrease. The main feeder roots on a mature tree are out in the yard somewhere not at the base of the tree like they were when it was young. Sorry if my advice was hard to understand.

Also, not all roots lay at the top 6 inches of the soil. Every tree has its own unique root system. Thats why, certain trees are drought tolerant and others can't take it at all. A lot of trees have a very deep root system so manual cultivation is not a problem, actually manual on trees period isn't a problem. Now, roto tilling is an entirely different story, for that you have to know the anatomy of your tree to see what if anything can be done.

There is an very EASY solution to your situation: In my landscaping business, I've done this dozens of times, in situations identical to yours! All you have to do is spread a few inches of enriched topsoil, like a mix of 50% pulverized topsoil and 50% compost to the entire area under the tree, but keeping about 18" away from the trunk. This will give you enough root-free soil to easily plant the groundcover plugs you choose, or even small plugs or pints of perennials such as heuchera. But, BEFORE you plant, mulch the entire area with the type of mulch you prefer, up to the root flare (which will leave you with the proper "doughnut" ring around the trunk). I find that it's definitely easier to plant the large number of small groundcover plants by pulling back the mulch (after it's spread), grabbing a handful of nice, loose topsoil from the uncovered area, then plugging in the (usually) peat pots of groundcover, finally pulling back the mulch to tuck them in. MUCH easier than mulching around dozens of little plants after planting! Established tree root systems can, in my experience and from what I've read, handle up to 4" of loose topsoil, even with 2" inches of mulch over that. In twenty-two years, I've never seen a tree suffer from this. In fact, most have actually responded favorably since the enriched topsoil gives a welcome nutrient boost to them! The new plants have a year to get established before the roots from the tree work their way up into the new soil layer (which they will). By that time, the new plants will be able to compete with the tree roots. Here is the Midwest, our sugar and red maples are usually the ones that need something planted under them because of their dense shade and shallow root systems. Even if one could somehow dig through the tree roots to plant, the new plants would have a terrible time getting established, and I really think that more damage would be done to those roots anyway! I hope this is good news!

Thanks for the ideas! I don't plan on planting too close to the trunk of the tree, so I will not be adding amendment to that area. It's kind of a big project (well, big because it's just one of about 20 things I have planned for the fall...), so I mostly want to focus on the more obvious area that is closer to the lawn. Eventually the plants will creep closer to the trunk.

HoosierGreen, I like your plan, esp. the idea about putting the mulch down before putting in the plants! I'd never have thought of that. I'm not sure if I can afford to buy enough top soil to put down several inches, though. I could get 15-20 bags like Kitten suggested, but I think that would only be enough for maybe an inch. Would that do the trick? The area is about 8'x10'. As I put in the plants, I could mix it up with the native soil. Like I said before, it looks like ok soil, but just compacted. I think a good layer of mulch will help alot. I'm thinking about doing the Chocolate Chip ajuga since I already have a few plants from last fall that are hanging on, and actually look like they're springing back to life a little. The problem with them was crown rot, which I'm finding is common with ajuga. So I'm not sure why I want to try again. I just don't like monkey grass I guess.

The ajuga I can find locally usually comes in 3-4" pots. Could I buy those and divide them into 3 or 4 little plants? Or should I just buy plugs online? I could also dig up the plants I already have and divide them. Thanks again!

This message was edited Aug 27, 2008 9:24 PM

Hey er: Can you find some good well rotted compost? Work that in with a fork - or even a small rake.
You won't get near the weed seeds you get with topsoil.

In an 8X10 area 15 bags is a great start. Mix it in with your soil and your off to a great start. Every year that you mulch you add to the soil, it takes time but thats ok. Ilove chocolate chip ajuga, one of my favorites. I too have had some troible with it. It doesn't like to get dry or if it thinks!!! it might get dry it gets funky. Even watering is the trick. Best of luck to you, I know your head is spinning off your shoulders but once you do it just once you'll see it's not so bad and next time it'll go faster, if you have to do it again.

In an 8'X10' area, a cubic yard of topsoil will cover to a depth of over 2", almost 3", and should be plenty for your need. Buying bulk is almost always cheaper than buying bagged (you would need to get a total of 27 cu. ft. to equal a cu. yd.), if you have, or can borrow, a truck to get it, to avoid expensive delivery fees. Garden centers sell bulk. Should be only around $35 per yd. for enriched topsoil. If you can mix amendments into the existing soil (not too many roots?), go with straight compost. Also, unless you mulch the areas you don't amend, any groundcover will avoid spreading into those areas. Mulch will decompose and improve the soil after a few years though, establishing a welcome area for groundcover. Buy your mulch bulk too, if you can.

i agree that top soil and mulch in bulk is cheaper, but it's also a lot more work. with bags you can drop them where you need them quickly, open them up, dump all bags, then rack into place. In today's world we have so little time that I started buying bag and have my clients buy bag because in the long run it's a lot easier and actually it's not too much more expensive because you have to either pay to deliever the stuff or pay in sweat from loading and unloading wheel barrels.I guess it comes down to how much time and money do you want to spend on the project.

Kitten-
We buy in bulk and just push it off the bed of the pick up. into the intended area. If I had to do it with a wheeled barrow.... ugh... Guess we have been fortunate to have the truck access to the bed(s)

There's a lot of value in "sweat equity" with DIY projects! In this case, a yard of topsoil isn't a lot of work though, and if you can back up the truck to the area, like missingrosie does, it's really a cinch. Regardless, no groundcover is going to do well unless given a good base of loose topsoil, preferably enriched. Like others have said, they will just sit there and not spread if the ground conditions are not favorable. Eventually, the mulch will break down and encourage any groundcover to spread, but it's disappointing to have to wait for that to happen. If you have a base of loose enriched topsoil, mulched, and plant the groundcover at a rate of one per square foot, it should be completely grown together, or nearly so, after a year. No more mulching would be needed then. In jobs that I have done, where the homeowner has extended an area of groundcover without amending the root-dense, compacted soil, the difference in growth is dramatic!

I have access to a truck but unfortunately where usually has to go isn't truck friendly. Many years ago i spread 1 tonof topsoil on my new yard. Needless to say I would have paid to have soemone else push the wheel barrow but it got done. Make sure you get good quality soil, my came complete with bermuda seed and now, 8 years later the whole front is covered in it. So, just make sure you get it from a good source.