Hi, newbie here. I am working on a small suburban property I purchased about a year ago in central Oklahoma. The property has three mature, aging silver maples on it, probably 30-40 feet tall. I dug a garden bed beneath one this spring, and have been contemplating doing a sheet mulch on this bed, as well as under the other two trees in another part of the yard to establish a windbreak on the north edge of the property. I am having second thoughts now, having read recently in more than one place that altering the level of the soil, upward or downward, can seriously disrupt the root structure of a tree or even kill it. I have thought about taking the trees out, but to do so would be way outside my price range, so they are staying for at least a few more years, and I don't care to have them fall over on their own. Any thoughts? What have others experienced gardening within the dripline of established trees?
Tree's are really good at stopping plants from growing under them. Shade tolerant perennials are what you want, and in bulk. Any productive annual (like cabbage or carrot (grown as an annual) or pepper is going to need a lot more sun that you can give it.
Maybe check and see if you have a neighbor who knows how to fell timber, a 30-40 foot tree is not that big, if you limb it heavily first it will be a quick and easy job, and you can start that hugle culture bed you've been wanting too.
i have found that the best way to garden under full size adult trees is to poke down with a metal rod and find out where the roots actually are, if they aren't visible.
then use something like a post hole digger and dig out the are where you want to plant and plant in that hole..if the tree has a lot of small surface roots you might want to plant in a bottomless pot large enough to contain the fullsize of the mature plant that you are planting, this will prevent the tree roots from coming into the planting zone..or at least help.
however..a mature tree generally has it's feeder roots out more toward the drip line ..so you should be able to plant a shrub or understory tree under your mature tree, or even some shade lovers..like hostas etc..with no problem
i have plants growing under all of my large adult trees, but i suit the plant to the tree situation and the openness of the situation.
under the deep shade of evergreens or low branched heavy shaded trees here i have things growing like hostas, solomons seal, lily of the valley , aegopodium, ..those with higher branches i have things like lilacs and elderberry and snowberry, and mock orange growing under very large established trees, i also have some vines growing up and through large trees like fox grapes, woodbine and clematis. There are currants and berries growing under some of my trees, and i have things like daylillies and iris and other perennials growing on the sunnier side of trees but under their driplines..in more open situations..it is always best to not have grass under your trees.
one thing i have found helpful is to work with what the tree produces..if it produces needles..you can pile the needles under the tree and grow your plants right in the needles..i have aegopodium and columbine and blueberries growing in pine needles..and then also under some maple trees i rake all the maple leaves back under the tree, it makes a great mulch and feeds the tree and also makes a base for growing things in..there are perennials and ground covers like aegopodium as well as shrubs growing out of this medium under my maple trees.
Bloom where you are planted.
Regarding your question - of course each tree has it's own 'best care' scenario and so I would focus on your Silver Maples.
I believe from all that I have read that as long as you make gradual changes to the soil level, do not expose roots and provide what your tree requires nutritionally all will go well. Many people do plant successfully under trees.
Why not start with the plants you've chosen planted into small surface mounds, only as high as the current root system of the plants. Place these here and there, under your tree depending on their needs for light. Then you can use the dropped leaves, thickly on walkways placed in and around the mounds, leaving them to naturally decompose and feed the tree and your plant mounds. As time passes you can expand your plantings, learning from your successes and failures. This way you move along a gradual path, learning and expanding and you won't shock your trees to death.
Silver Maples are known for their invasive roots (and brittle wood), so unless you address this issue they will eventually grow into your soil mounds. This may or may not be a problem depending on the plants you wish to grow. For example I find root competition and shade a very good thing for herbs and things that love to spread like mints, violets, horse radish and some ivy. But very bad for my summer vegetable plants.....
Also consider, while your planing your soil level adjustment and plantings - having some depressed areas around your trees/plantings to capture rain and hold it in your yard instead of allowing it all to just run off.
Post hole diggers and mounds ought to give me something to work with! I was looking for somewhere to put horseradish too. As far as hugelkultur goes, the maple has shed plenty of wood this year alone to start a nice sized bed or two, all stored neatly in the back corner. Now I'm just waiting for the 100 degree temps to end. Thanks all!
My current garden here in our urban rental home in Oregon is situated so that a little more than half of the garden is outside the drip line of a large apple tree. There is also an English Laurel hedge on the other side of the garden and a ~15-20ft dogwood tree nearby as well. Anyways there has been a horseradish plant under the shadier part that survived at least 2-3 years under a tarp before I even moved here. Since moving here it has been pretty fun seeing what will do well in my garden since no part of my garden gets true full sun. I've managed to grow some stuff that needs full sun in the brighter parts with much success and have started a lot of things that grow easily and are handy. This year I planted an excessive amount of Nasturtiums which I had read are beneficial companion plants to apple trees (among other plants) and a few that were in the shadier parts and a bit weaker than others acted as pest traps for black aphids. I've read that the spicy scent of Nasturtiums also drives woolly aphids off of apple trees and this year the apple tree appears a lot healthier than in the past. Many more fruit are turning out nicely too but I suspect this year is an "on" year for the tree.
I rather enjoy working with the trees around my garden and have been successful growing a number of herbs from Echinacea, comfrey, borage, nettle, mints, salvias, to woody plants like currants, elderberry, wintergreen, rosemary, lavendar, and a tea Camellia...you can really get away with a lot more than you might think sometimes. I also planted some shade-loving natives like indian plum and deer fern which are making good use of the extra shady spots. Not that cutting down the trees isn't a viable option - I'm sure it'd be a nice harvest and a brighter, more productive crop for vegetables and full-sun plants. The trees and hedge around the garden protect it from wind and drastically alter the atmosphere of the garden. I haven't had any experience with silver maples though and Jami's response doesn't sound encouraging.