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How can I fertilize trees under flagstones?

5 days ago

I have a courtyard that is flagstone laid on a deep layer of sand. The drainage is excellent as a result. There are four trees in planted in it - dogwoods and a weeping beech. Their drip lines go beyond the the mulched areas around the trunks, so they must essentially be growing in sand now. I thought it would be a good idea to fertilize them, but realized that the instructions on Hollytone for established trees doesn't apply. I can't dig three inch holes at the drip line. There is also a weeping Japanese maple and a weeping cotoneaster planted in a mound of rocks that is a waterfall. It seems to be hollowing out, as I can see large openings. I think these must also need replenishment of soil and nutrients. How are trees planted in terraces fertilized? It's not exactly like container gardeniing, but it isn't normal ground gardening either. What would you do?

Comments (4)

  • floral_uk z.8/9 SW UK

    I've never fertilised a tree or shrub and my whole garden is paved and walled. There is a 30 year old Parthenocissus henryana vine growing five storeys up the back of my house planted in a foot square of crappy soil where one flagstone was removed for it. It too has never had so much as a teaspoon of fertiliser. I don't think yours trees will need it either.

    kitasei thanked floral_uk z.8/9 SW UK
  • ken_adrian Adrian MI cold Z5

    on my 5 acres ... i have sand at least 5 feet deep ...

    i have also never fertilized my trees nor shrubs ....

    if you are presuming.. just because it is sand.. they need to be fed ... perhaps that presumption is wrong ...

    do you SEE any real need for such???

    imo.. save your money ... and find something else to use your time on ...


    kitasei thanked ken_adrian Adrian MI cold Z5
  • kitasei

    Thank you both for your reassurance. But I am still puzzled about the science. Trees need some soil, do they not? Whether inferior like yours, Flora, or sandy like yours, Ken. I am talking about pure sand a foot deep beyond the small areas where I planted the trees. Do the roots now reaching out into this sand simply need oxygen and water? Ken, you ask if the trees seem to be ailing. Not the old dwarf weeping beech, but the established dogwood could be better. The other dogwoods are newly planted. Lord knows I have enough other things to spend my time and money on, but I'd hate for these not to thrive.

  • mad_gallica

    We are back to the plant literacy problem. Plants can't read. So they have absolutely no idea what we are reading about them.

    Somewhere, you read that tree roots always stay in the top foot of soil. Your trees never read that, so have no idea that is how trees should behave. If the water and nutrients are deeper than that, they will grow roots deeper than that. Unless there is solid rock beneath that sand, I wouldn't worry about it.

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