hardpan in Snohomish

Discussion in 'Outdoor Gardening in the Pacific Northwest' started by BethSnohomish, Jan 20, 2006.

  1. BethSnohomish

    BethSnohomish Member

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    Beautiful! I'm so glad to be here, finally, where things grow.

    Ok, another question - today, in planting some Alberta Spruces, I found that directly below the thin layer of amended topsoil put in by the previous homeowner, is hardpan. VERY hard clay, with rocks under it. I was wondering, is this the normal soil for this area? And if so, how does the water drain through this? Do you all plant in it anyway, or do you amend the soil first before planting anything - or, do you, as this homeowner did, put a thick layer of amended topsoil over the top of the hardpan and then plant in that, obviously hoping to give the roots a chance to establish before they hit the hardpan and to help with drainage.

    More questions - when I dug through the hardpan, it had sort of a rotten smell - Im sure this is due to the constant rain, but is it really rotten, or is that just the normal smell of this soil - because I dont have experience with it. Another question - without testing it, can I just ask is this soil basically acidic?

    Lastly - is this hardpan clay the normal soil, or is it a result of the housing developments rolling around on the soil with heavy machinery until it became hard packed?

    Please forgive me if the questions sound lame....
     
    Last edited by a moderator: Jan 23, 2006
  2. Gordo

    Gordo Active Member 10 Years

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    I wish I could insert that noise that Lurch, of the Addams family used to make here. Welcome to the wide wonderful world of glacial till, hardpan/rocks, and septic systems gone amok. I'm no soil expert, but the conditions you describe are not unusual for this area - it sounds a lot like our last place. I think you've already figured out the two main options; amending the soil, which can be done with the pick & shovel, "a little at a time" approach, and/or the mounding/berm idea, which is more costly, but almost certainly less labor intensive, and can result in a most pleasing result, as the plants tend to show off to greatest effect. Our soils do tend to be acidic, due to the amount of rain, but a soil test is never a bad idea. I would suggest you hire a couple of neighbor kids to help you out, if you can find any who will work that hard (doubtful).
     
  3. BethSnohomish

    BethSnohomish Member

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    ****sounds of Beth laughing wildly at the thought of neighborhood kids actually offering to help out....or even at the thought of helping out even after she offers to PAY them for that matter****

    Heck. I can't even get the SO to help out. Sigh. I need a gardening guy.
     
  4. Dee M.

    Dee M. Active Member 10 Years

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    I've known people who live in the new housing developments in Snohomish, and yes, they did scrap off the topsoil, if there was any, brought in fill dirt and ran heavy machines on it, then they brought in 2-3 inches of topsoil when they were done. The soil shouldn't smell rotten, it should have a slight compost pile smell if you know what I mean. So those are your two options, berms or amending large areas. There are guidelines to amending soil, it is impossible to do enough for large trees and shrubs so it can do more harm then good. I think mostly doing berms, with mixing in the soil at the transition line, is the way to go. Some shallow rooted perennials that don't need great drainage might work with just amending the soil. By the way, what they did to the soil will make it hard to have a good lawn because I know they just roll on the sod on top of the 2 inches of topsoil. Even if you didn't have the new housing development problem the soils around here vary greatly, your soil might be different from your neighbors down the block. On the soil acidity, I would say you are safe assuming it is at least slightly acidic.
     
  5. BethSnohomish

    BethSnohomish Member

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    Thanks Dee - fortunately the grass is already established and there is precious little of it - we live in a housing development that borders on greenbelt, but as a resulting tradeoff I guess, we have very little lawn. I think a pushmower would do the job, nicely. After we put in a deck, there will be even less - so I am counting heavily on the greenbelt border to do a lot. We have a small area that is just to the southwest of the greenbelt, and I can plant it - as well as the established borders that surround the house - the lady was very big on flowering shrubs which I am very grateful for - but I have to wait a whole year of course to see what actually comes up. Having lived in Nevada for 20 years, Im not even familiar with what some of the dead plants look like here (I mean "wintering" plants, actually) so I won't know what they are til they come up and blossom.

    I paid a WONDERFUL visit to World of Flowers today - oh my heavens such a wonderful place! I had done my homework so I recognized most of the plants - I have to say my favorite simple little groundcover thus far is the two colors of baby's tears. They look like little puffs of green everywhere soooooo pretty! I didn't buy anything today - was just taking "inventory" of what was available. I can't wait to come back when all the bulbs are blooming to see the spring groundcovers, etc.

    I thank you for your advice on the trees - I can remember reading somewhere that if you dig a huge hole for a tree and amend the soil, when the tree gets to the edge of the hole it acts like its in a pot and can choke itself on its own roots since it doesn't want to leave the amended soil. Guess there is some logic to that - I want to get several native variaties of conifers - especially the beautiful cedars - so Im sure its best to pop them in the unfriendly soil they are used to.

    I ALMOST called you today to go to Flower World with me, Dee - but it was raining pretty heavily, so we'll wait til there is a prettier day. :-)

    Beth
     
  6. Gordo

    Gordo Active Member 10 Years

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    Beth, you wont miss the lawn. These are rather boring, high-maintence items anyway. In the areas you don't want to plant, think hardscape - stepping stones interplanted with the ground cover you mentioned, or others look fantastic and are relatively easy to do, especially with the nice hardpan base you have. Potted plants can work too, for either short-term, or long-term solutions. One more great local resource I would mention for you to check out is Stubers in Snohomish - a great source for potting soils, fertilizers, etc. Think spring!
     
  7. Ron B

    Ron B Paragon of Plants 10 Years

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    The roots not leaving the hole is a myth. The main problem with amending planting holes is how movement of water into and out of the amended hole can be affected. During moist conditions amended holes may collect water from unmodified soil around them, during dry they may shed water to it. This results in stunting of the plant, until it roots into the unamended soil around the hole - or dies if moisture conditions within the amended area are severe enough. Plants pulled out of amended holes that haven't rooted out of them did so because they were in poor condition, either before planting or after (due to above described problems).
     
  8. Weekend Gardener

    Weekend Gardener Active Member 10 Years

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    If I have a location which is a completely empty canvas, then my dream plants to fill it would be:

    1. Sarcococca
    2. Skimmia
    3. Hostas, and more hostas
    4. Ferns, ferns and ferns
    5. Mahonia
    6. Trillium
    7. Indocalamus tessellatus

    These are all doing well in our garden.

    And no - no vines please - no ivy, no vincas.
     
  9. Gordo

    Gordo Active Member 10 Years

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    Re: Best Shade Shrubs/Perennials to mix with old Rhodos & Heathers?

    Amen.
     

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