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Failure due to allelopathy

8 years ago
last modified: 8 years ago

I feel a little guilty. I've had some roses that didn't do well and I trashed them. Now I feel guilty because I planted other things in the same spots, and although they do well in other parts of the garden, they have also done very poorly in that spot. Then I noticed that all the roses that were within a certain radius of the hawthorn tree (up to slightly outside of the drip line) are doing poorly even though they get full sun and well supplemented moist soil. The same varieties planted 2 feet further out are doing fine. It's a circle of, well, not death, but almost, around that tree. I'm chalking it up to allelopathy because the hawthorn tree is also in the rose family which is known for making chemicals which inhibit the growth of plants within the same family. Some roses that were doing poorly in the spot are now doing fine in pots (I thought it was due to being in rich potting soil vs. the ground, and that may be part of it, but maybe not). The other thing I noticed is that the very same variety of rose (Alnwick Castle) does just fine growing directly under the branches of a large pine tree. So now what to do? The circle of death is in the center of my main rose bed. Should I plant other plants in those areas (the irises that I tried there are fine, and plants not in the rose family would do fine if my guess is correct)? Or should I remove the hawthorn tree (although I don't know how long it would take for the inhibitory chemicals from the hawthorn tree to degrade or get washed out of the soil)?

Comments (9)

  • 8 years ago


    I would try other plants ans see what works

    Sometimes it is trial and error is isn't it. I have lots oof salvias. Some in partial sun, some full sun. They don't seem too picky.

    noseometer...(7A, SZ10, Albuquerque) thanked Kristine LeGault 8a pnw
  • 8 years ago
    last modified: 8 years ago

    If I were in your situation... I'd remove the hawthorn tree, plant something else in there for a season or two then slowly try roses in that area again...But that's me...lol

    Depends on how much you like the hawthorn tree etc... What do you want to do??? That's what you should do...lol...Follow your heart!

    noseometer...(7A, SZ10, Albuquerque) thanked jim1961 Central Pennsylvania Zone 6a
  • 8 years ago

    Thanks, Kristine and Jim. Both options would work. I don't really like the hawthorn tree: I've impaled myself on the 2-inch thorns too many times (right in my head, accidentally standing up under the tree), and in my garden it tends to defoliate by the end of summer., so there isn't much fall color. The birds eat all the berries so there is never much fall or winter color from them either. I'm just waffling because it does cost a bunch to have someone remove something that size, and will it be worth it if I still can't grow roses in that area? I guess it would be worth getting rid of Vlad the Impaler.

  • 8 years ago

    So would I . It sounds to me like this tree is just an all-round loser,unattractive, physically hurt you, and seems to poison the soil around it. Worth paying to get rid of it,roses or not. And, once it's gone, you can try "the box technique". Here in Europe we have that mysterious "rose replant disease"; I gather it is particularly bad in England. So one way to get around the problem is as follows: work the soil well, then dig a nice, big rose hole. Line the hole with cardboard,or use a cardboard box. Then you plant your rose in the box, using fresh native soil from some place that doesn't have the problem (of either the hawthorn "poison" or of having had a rose grow in it before). The idea is that the cardboard forms a barrier for a while, to allow the new rose to get started without the competition of the wierd soil; by the time it rots, the rose (hopefully) is big and established enough to duke it out on it's own. And I would probably start by trying roses that are known for vigour, that have been growing in pots for a while, so they've already got a good start.

    noseometer...(7A, SZ10, Albuquerque) thanked User
  • 8 years ago

    Bart, what a cool idea.

    Diane, you know that we have dug out 70 shrubs and a huge half dead crepe myrtle, so, I basically sleep with a shovel in my hand

    I say get rid of Vlad and it will open up the area with beautiful streaming sunlight. Even if you never plant a rose there just having that ugly thing gone will make you feel so good.

    noseometer...(7A, SZ10, Albuquerque) thanked Kristine LeGault 8a pnw
  • 8 years ago

    " I basically sleep with a shovel in my hand " Chuckled at that one Kristine...lol

  • 8 years ago

    Well...I make Vlad out to be uglier than he really is. He is a pretty tree... from a distance when he isn't playing the impaler and when I'm not afraid of having an eyeball speared, and he has nice looking branch structure in the winter. And we get so much sunlight here that any shade is a blessing. But you are right. I've never been happy with him and his wickedness. Kristine, you must be very strong. I dug out 14 trees when I moved into this house, and swore that I would never do so again.


    Thanks for the idea Bart. I would never have thought of doing it that way. It must work if they do it that way in the land of rose replant disease.


  • 8 years ago

    I remember ordering 4 edible pear trees from Michigan Bulb one spring. The whips came and I planted them on an espalier frame, pruning them as required for my pattern. I was astounded when late fall came to see thorns on them! I wrote Michigan about them but they never said what they were. After a lot of hassle they sent me a certificate to reorder replacement pears in the spring. By then the trees had thorns long enough to make sewing needles for leather or fish hooks for salmon! Yes they were very healthy and are supposed to be loved by birds but not by me!! I put the replacements in the same holes and never had any problem. Maybe they were too young to have contaminated the ground.

    noseometer...(7A, SZ10, Albuquerque) thanked lkayetwvz5