That must be some tree!

I just mow my volunteers down. Eventually they give up.

Far as what to grow under it....probably nothing five feet from the trunk! Maybe out near the drip line you can get some dogwoods or redbuds or serviceberries to grow. They are understory trees naturally.

Just promise (and the oak) you will not do any massive soil changing construction under it. Trees despise soil level changes.

Something to consider - sometimes when large white oaks get stressed, they sucker in mass number from the roots. This is the main way the crosstimbers region is forested by post oaks. I had a 100+ year old post oak do this in my yard after a storm blew the top 1/4 of the tree down. Not sure which species of the white oaks have a greater tendency to do this.

I am really just asking if you are sure the tree is healthy :)

John

PS - I will post a link about the crosstimbers history when
I find the one I was looking for. Oaks suckering from the roots was a new one on my when I heard it. Then I saw it in person!

Edit: I found the link. A plant ecologist talks about the forest content around the 3:00 minute mark and forest regeneration around the 5:45 mark

Here is a link that might be useful: Oklahoma Gardeing - Keystone Ancient Forest

This post was edited by j0nd03 on Mon, Jun 10, 13 at 9:35

Don't put any more than 1-2"/year of compost/loam over the root zone...you'll kill the tree. Oaks are among the least tolerant trees of root zone disturbances.

As for growing plants underneath; White Oak generally has deep roots thus reducing the direct competition for soil moisture between the tree and your plantings. The polar opposite of maples!

Dear All,
Thank you for responding. May I clarify a little bit: the canopy under the oak is quite large, because the oak itself is quite large. So when I talk of putting a layer of dirt under the tree, this would not be a major layer of dirt (3" perhaps). Now, I don't think the oak is ill, I haven't done anything to disturb it. It's a big tree, large numbers of acorns fall, they sprout, I didn't catch it in time (my attention was elsewhere in the garden).
I expected more comments on the symbiotic nature of some plants with oak. Oak lives are more acidic than other leaf litter, so I have heard. Aren't there any plants for whom oak leaf litter is a godsend? For whom, this acid in oak leaves is the specifc thing they crave?

I don't think Oak leaves hurt other plants all that much, except in that they can form a "mat" and don't decompose quickly.

AbsentMindedOwl,
Let me make it clear.

DO NOT PLACE 3" OF SOIL/COMPOST ON TOP OF THE ROOT ZONE OF YOUR WHITE OAK!!!!!

White Oak are EXTREMELY sensitive to root disturbance, and a very large tree especially so. Large trees are precariously balanced between, root growth, seed production, shoot growth, and wood production. The leaves can capture only so much sunlight, and that has to be converted to so much biological compounds. If anything is significantly disturbed from that balance (except seed production), and you can push a large tree over the edge rather easily. Not to say it would die immediately, but it would decline over a period of time.

Keep the compost to 1/2"-1" at most, and I would leave the soil out completely. As for the seedlings, even if you cover and kill this years crop, the next crop will just repeat. And if you stress your tree with too much root cover, it is likely to seed extremely heavily as "it thinks" it is going to die, and much produce as many offspring as possible. Just use glycophosphate (i.e. active ingredient in Round-Up) if you can't mow them. This will kill the seedlings, and bio-degrades very quickly in the soil, so you won't be "polluting the earth" as some people would say.

Arktrees

Depending on where you live there are many plants that thrive underneath large trees. Examples are Azaleas, camellias, Hydrangea, red bud trees, dogwood trees, to name a few.

Flowering and graden plants include Hostas, primroses, Lilly of the valley, ferns, etc.

The best thing would be find an old nursery with knowledgeable people. Not your average big box store.

The other way is to talk a walk through your neighborhood and see what others have planted. Talk to the older residents as they have probably already tried many things before they got something to grow.

Arboretums and parks are another place to learn about understory plants in your area.

I have a long list of shrubs under my pin oaks. Pretty much anything you can think of that can handle sun/partial shade/shade. The only trick is to plant them small so there isn't a lot of root disturbance planting them. Roses, hydrangeas, viburnums and other usual suspects are on the list

The biggest problem I have with oak saplings is that there are these creatures, with hands and inhuman intelligence, that think one of their missions in life is to plant acorns.

it would be easier to list what wont grow under an oak..

rather than list what will ...

there is no bounds to what you can do..

and there is absolutely no reason to add soil .. total waste of time and money ... let alone effort ..

you are way over thinking this..

==>> buy plant.. dig hole ... insert plant .. preferably roots down.. water .. enjoy..

whats next.. you going to rake up all the tree made compost ... because it looks messy ... because you want to see bare dirt???? .. or truck in colored mulch.. because you prefer adobe colored wood chips ... oh man.. my heads spinning... lol...

seriously.. see above re: dig hole... good luck....

ken