Soil problem

[Grey]

Right. The part that seems odd to me is.... I've seen tree roots do just fine in this clay.

So if roots are used to a soft life going through compost, then hit the clay - are they not going to be tough enough to go through the clay?

And - over time - wouldn't the compost and the clay begin to mix some at the edges - providing a "transistional" area?

Theoretically speaking of course.

[The Helpful Gardener]

What you describe is called a soil interface, Grey. Roots don't stop, but they do stall when they come to one and that bathtub effect can cause trees to tip in very windy conditions, especially when they are young. Eventually roots will cross the interface, but it can stall them for a year or two. Mixing the soils with the compost can help some, but now we have another soil interface. So there is the root ball to compost interface, then the compost to clay interface. Simply planting in the same soil and allowing the nutrients to leach into the soil creates one less interface (only rootball to clay in the other model)...

For veggies and such, with smaller roots, creating the nice soil is more beneficial. But for trees and shrubs, no ammending and improving soil from the surface down is the best approach. Opa is right again...

HG

[Grey]

Ok - now I understand. Thanks!

There just seemed to be too many schools of thought around me locally - so thanks for clearing all that up!

[opabinia51]

Scott, that had to be the best description that I have ever read. That was amazing, it was like a national geographic narrator stepped into the website.

Anyway, yes, I agree with all that you said and just to add a bit,


Yes, tree roots can pentrate hard, compact surfaces, they will even grow through concrete and eventually break it up into what is the genesis of new soil (many centuries down the line)

[The Helpful Gardener]

Not that we recommend it...

HG

[opabinia51]

Well...

take for instance some building in the middle of central British Columiba that has been abondoned for many decades. All that remains is the foundatation and slowly over time the tree roots break up the foundation into a crumbly mass that with the addition of leaves and needles (which, are leaves) from the surrounding trees will be a nice soil. That's a good thing.

A BAD THING:

Planting a Weeping Willow next to the foundation of your houe or next to a patio or even worse, next to a septic system. NOT A GOOD THING.

So, I say: Choose your battles

[The Helpful Gardener]

Sure. A Tree Grows in Brooklyn. An Ailanthus altissima, a Tree of Heaven. At least in Central China, where it comes from that's what they call it. I call it a non-native invasive, so I have to ask WHAT trees are repopulating those buildings before I'd greenlight it all the way...This is one of the real badguys; bet you and I share this one Opa. Found in forty two states including Hawaii and a specialist in urban survival...


http://www.nps.gov/plants/alien/fact/aial1.htm

[grandpasrose]

I agree Scott that Ailanthus altissima (sumac) is a wild spreader. Not to argue the need to be aware of the plants that are invasive and noxious, but I hesitate to use this list of plants as THE bible. Look at the plants listed on it - apples, celery, asparagus, lilac, and garlic, to name a few. I think I would take this list with a little bit of caution.

Val

[The Helpful Gardener]

No Val, garlic mustard ain't garlic; it is a horrible invasive in much of the country (mustard is prodigious in seed production, as often mentiioned in the original Bible)...Can't find the other plants you mentioned on the invasive list...

http://www.nps.gov/plants/alien/fact.htm

HG

[grandpasrose]

Scott, that address takes you to the list of the plants that they have complete fact sheets on, but if you go to the home page, the link for the FULL invasive list is there, and all of those are on it, including the real garlic.

Val

[opabinia51]

Hey Scott, are you referring to me agreeing with you about this invasive? Just not clear what you are asking.

Yah, I do agree with you.

For British Columbia I generally refer to the BC invasives list. I posted it somewhere else in here when Val and I were discussing the topic some months ago.

[The Helpful Gardener]

Look at who is compiling this list Val. Foresters, ecologists and scientists from the state and federal parks and only when they find plants out of bounds. If those plants are indeed on this list, we should look carefully..,

On the other hand I was on the CT INvasive plant listing and they jad incorrectly listed Acer pseudoplatanus , (that grows in my yard and I have NEVER seen a seedling) instead of the horribly invasive Acer platanoides, the one that SHOULD have been on the list. So always worth doing your homework, but we need to look at this carefully...

HG