Building soil and understory under existing oaks in Texas

Hi Steve,
Congrats on the book coming out!

I live in the suburbs of North Texas, in sandy-clay loam soil (locally called Cross Timbers soil) where the climax species is post oak (Q stellata). My half-acre lot is still about 1/3 covered with regrowth oak canopy, and I'd like to grow forest edibles and medicinals there--ginseng, goldenseal, black currant, etc. Unfortunately, the previous owner was removing all the leaves and putting out chemicals to try to grow a lawn. The soil is very depleted. I'm trying to grow some cover crops, put out some mulches, make some compost, but without much of a plan.

How should I best rehab my soil under the oaks to make them healthy and establish a productive understory? What would be some support-species plants for this situation? (Zone 7b. 30" annual rainfall. hot, dry summers)

Hi Kerry:

It sounds as though you are on the right track. Are you able to have animals in your neighborhood? I would highly recommend ducks along with the heavy addition of free local sources of dead organic matter (bagged leaves, woodchips, etc) mixed with successions of cover crops, to rebuild soil.

Some oaks will probably need to be thinned and could be good candidates for shiitake. Since you are in a hot climate, look to use the "warm weather" strains. Our buddies at Field & Forest have some of these, see our page on the farmers we profile in the book for a link: http://farmingthewoods.com/the-farmers/.

I'm not sure you will have the best luck with ginseng and goldenseal, as they like it cool, and wet. Currants are a good choice. Paw Paw might be one to consider, though you are out of its nature range.

Hope this gives you some places to start!
Steve

If your going to disturb within an large oak tree's canopy, you might think about only disturbing 1/3 or less of that area, in any given year, to protect the tree itself.

If you disrupt the soil 100% in a single year, you could lose the Oak, perhaps not immediately, but because you drastically changed the water holding capacity of the area.

You might think about using a root barrier fabric, perhaps thick cardboard barrier, or root barrier bags for plants that you intend to live under the canopy, Oak trees will consumer nearly all available water, and will naturally grow new 'fine roots' into any soil amendments added under the canopy within a year or two. Becoming invaded by the fine Oak roots, thereby robbing any plants that you place within that area, of water & the nutrient that was part of your dirt improvement plan.

If you were going to try goldenseal & ginsing under a TX oak for example, you would probably have to water it a great deal, which without a root barrier between the oak tree's root system and your plants, could cause the oak tree to absorb more water than 'normal'...thus affecting the tree, by weakening it's natural water uptake.

I'm not saying it cannot be done, rather, be a little careful about affecting a large area in any given year, spread your improvements over 3 or more years.

As far as roots are concerned an oak tree's roots are not that much different than a maple's....try googlesearching: roots invading garden

james beam

Steve--thanks! I had not really considered ducks--don't know much about them. A friend has muscovies. Mushroom culture has been a back-burner idea. I'm not sure whether wood from my property would be "clean" enough to use for that. I've preordered the book, so I'll be awaiting its arrival!

James--wow, I hadn't thought of root competition this way: "an oak tree's roots are not that much different than a maple's". On this property (sandy soil, people interactions), if I dig 3-6" to remove a greenbrier or chinaberry or bamboo, I never find an oak root. But I remember at my grandmother's place near here, where the red clay was at the surface and the interactions were with cattle, the oak roots were all over the surface of the ground. Hmmm... It will be interesting if I add compost and mulch to see whether oak roots come up to grow into those. I had not thought about this. I would be happy if the oaks just got a little healthier.

Changing the soil water holding slowly is probably a really good idea also--not all the oaks are all that happy as it is. It is hard to know what-all the previous owner did to make the oaks unhappy. The neighbors have very compacted soil and they also remove all the leaves, but their oaks are in better shape than mine. My previous owner probably irrigated more and applied more bags of stuff from the big-box store than the more lackadaisical neighbors do.

Thanks also for the root-barrier ideas for the water-loving species.

Thanks also for the root-barrier ideas for the water-loving species

I don't think I was very clear about 'water-loving species'...but I know a little about goldenseal that grows wild on my property. In the wild it might receive a good amount of rainfall thru the year, an dry spells exist also, but because it lives under the forest canopy, it usually rains quite a while before the rain actually begins to permeate the ground directly. Full shade after 11am. would be good to have.

~~~That being said, the dirt generally should be consistent in moisture content, whether it is raining or not, my dirt is 2/3 sand & gravel so it naturally drains quite readily, and yet it retains some moisture at all times, it is never 'powder dry', and never soggy even during a big rain. Because it is well balanced darkish brown dirt among the gravel, and there is lots of other roots, canopy shade, a good amount of shrubs and other 'forbes', and variable amounts of leaf litter build up, all of which keeps the ground 'cool', slightly damp, even thru July & August. Hope that makes sense, but it may be very difficult to keep your N. TX ground temperature cool enough, moist enough, drained enough, and rich enough to grow ginsing and goldenseal~~~

Now if you had a nearby creekbed, or wet weather dry creekbed nearby, if you can find an area that has 'the richest dirt' still intact, and not likely to wash out nor flood anytime soon...might make a good spot to try ginsing & goldenseal. 1 ginsing plant needs it's own 1 square foot of ground, he can be crowded by other little plants like phlox, flowers, grapevines, but he likes it if he has his own spot, goldenseal will grow 2-3 plants in a square foot, depending on which other plants are trying to overcrowd it, a big clump of fescue grass could be removed from that area for example. If I was trying to plant ginsing or goldenseal in a good spot and I ran into a 1" or larger tree root, just go beside the tree root and try not to nick it badly, goldenseal & ginsing once established will grow among the structural tree roots, no problem...in these conditions manmade root barrier is not required. I love the look of both goldenseal & ginsing growing, digging the roots never interested me nearly as much as the beauty & value of the above ground part.

What size are your 'regrowth post oaks'?---the diameter of the trunk, on average? You might try some invasive ground vines to help hold dead leaves, something like poison ivy, or poison oak, virginia creeper, and/or the possibly some native honeysuckle (kina slow to grow). Most plants will grow up thru ground vines, but sometimes the vines want to grow on the plants...so there is that! LOL

james beam

i'm really excited to have found this thread, i am trying to get permaculture going on a suburban plot and have a yard full of post oaks.

i have a pond and am looking for things that would grow around the pond under all the canopy.
how is your yard coming along, kerry? did you ever get ducks??

Hi Kristen,
Congrats on post oaks and a !!Pond!!.  So awesome.

I'm afraid that I haven't gotten as far as I'd hoped in the area where I'd wanted to make an Eastern forest-y looking area under the densest shade of the oaks.  Since we moved here in 2013, I've just added bagged shreaded hardwood bark mulch and a large quantity of banana leaves that a neighbor put on the curb.  Plus I chop and drop comfrey, cherry laurel, and lambs quarters there, and don't remove the oak leaves.  That's about it for soil building in that area.  We never got ducks--I think they would be more work than my family would want (for us, since we don't have a pond).  We have chickens, but they have not spent any great amount of time in that part of the yard.

In this poor soil area under the oaks, it does stay drier than elsewhere, so I've been using soaker hoses.  With the soakers, I'm having fair success with Russian comfrey, valerian, tea, lemon balm, yellow columbine, improved autumn olives, and recently figs.  Old bush roses, blueberries, strawberries, and bearded irises just sit there not growing much, but blooming a little.  Goji, goumi, and the forest species mentioned in this thread are not growing at all in this location.   What really wants to there grow are bird-planted cherry laurels and mulberries.  And you could do worse than those, honestly.  Both are great for birds and for chop and drop.

My focus with plants has moved to the opposite side of the back yard, where everything is doing much better.  And to containers for the water lovers, which aren’t doing all that well, so far, but I just started that in june or so.  Need to learn how to fertilize those.

I would think your pond would change everything!  You could grow all kinds of things that like it a bit wetter.  Reeds, irises, cannas, violets, horse tail, all the mint family, elderberry, bamboo.  Turks cap will still bloom in deep shade.

I think James hit the nail on the head (above) about the oaks keeping the ground too dry.  Things grow fine next to one isolated oak.  But in a grove of them, I haven’t found the magic formula yet.  Since I have other parts of my yard that are sunny (because the previous owner killed the oaks ), I don’t want to thin them, as Steve suggested above.  I think if I had them thick over the whole yard, and it was big enough, I would consider it.

Let us know how your project goes.  We must be pretty near each other!
 

some undergrowth species I grow under my red oaks here in N. Texas are redbuds, mexican plums, vibernems, beutyberry and elderberries. Elderberry doesn't need as much water as you think, the european variety at least has done good on the forest edge to full forest shade. use mulch pits near new plantings to increase water near these new plantings. I have tried to grow ginseng drylands here for going on 8 years w/ no luck, summer to dry, oak leaves to big. I also have everbearing strawberries under my oak forest and they are slowly expanding and even give a few intense flavored strawberries.
I am working on a 6th generation shade tolerant triticale, 3 generation spaghetti squash grown in shade. These are land race varieties I am working on. Chicory grows well in the woods. All these I grow in our oak overstory, dryland and have some success and failure. Good luck on your venture

i love the idea of everbearing strawberries!

chris cromeens wrote: I also have everbearing strawberries under my oak forest and they are slowly expanding and even give a few intense flavored strawberries.

do you find that they are healthy and not giving berries due to the shade?

Hi Kerry,

I am new here and saw your post. I have huge full grown oaks in a woodlot here on Long Island, NY, but my climate is zone 6B and much different than yours. I was wondering, how close to your mature post oaks did you plant your comfrey? My mother gave me two plants and I have one specimen tree that was struggling due to construction mounding from the previous owner and of course grass. I have worked with a ring of mulch and the soil is much improved, but I thought I would plant the comfrey around the tree. Wondered at what distance you planted your comfrey. The tree was rather stressed and I don't want to disturb it with roots too close to its space. I will do as you have, the old chop and drop. Been doing this with wild dock as well and nettle in other areas of my yard, but wanted to feed my tree from a close proximity. Any help would be much appreciated!

Alex

Alex,
How is the comfrey doing?  Our soil here is so dry in the summer that the comfrey doesn't spread much.  For me, I don't think the big oaks are going to notice a few clumps of comfrey much.  Some plants are within a couple of feet from oak trunks, while most are within the drip line.  I hope the comfrey is nourishing soil- and insect life that will benefit the oaks indirectly, but not as a direct remediation like you asked about.  The comfrey is the first thing to wilt, so I use it as an indicator of when to water (it perks right back up).  I have only Bocking 14, so it doesn't reseed.  The dry summer and poor, sandy soil keep the comfrey from spreading--at least so far (I've grown comfrey only since we moved to this place/soil 4 years ago).

Your situation on LI would likely be very different, with more water.

Kerry Rodgers wrote:Hi Steve,
Congrats on the book coming out!

I live in the suburbs of North Texas, in sandy-clay loam soil (locally called Cross Timbers soil) where the climax species is post oak (Q stellata).  My half-acre lot is still about 1/3 covered with regrowth oak canopy, and I'd like to grow forest edibles and medicinals there--ginseng, goldenseal, black currant, etc.  Unfortunately, the previous owner was removing all the leaves and putting out chemicals to try to grow a lawn.  The soil is very depleted.  I'm trying to grow some cover crops, put out some mulches, make some compost, but without much of a plan.

How should I best rehab my soil under the oaks to make them healthy and establish a productive understory? What would be some support-species plants for this situation?   (Zone 7b.  30" annual rainfall. hot, dry summers)

I worked the last 18 years at repairing soils all over the state of TX... Taking tired, chemically "nuked", seriously abused dirt and transformed it into vibrant nutrient dense water retaining soil... Some instances taking as much as five years but most often within two or three and often as little as one... The most cost-effective way that I have found outside of just letting nature run its course was through addition of microbiology via liquid compost extracts as well as additional organic matter... The current Texas expert on the subject is Betsy Ross at Sustainable Gowth Texas...