What was used to kill the stumps? I think that's important to know.

And how long ago? Bulba cut down a large conifer in our garden and extended a raised be to bury the stump but did not use any form of stump killer on the stump. We were able to plant immediately the soil had settled.

I would not have poisoned the roots/stump either: conifers do not grow back. The poison stays in the ground for a long time, sometimes years, so even if you plant lots of soil above the site, any new plants roots will eventually grow down into the poisoned soil.

Best you can do is remove as much of the roots and poisoned soil as you can and then put in lots of fresh soil.

I have to agree with Kildermorie, you should have taken the roots/stumps out in the first place. Yes is does incur extra expense/effort but leaving the stumps in nearly always comes back to bite you with problems you don't need.

Jimmy if Drdavies hadn't used stump killer there would be no need to remove the stumps or roots. As Kildermoire states above a cut down conifer does not grow back. We've got the stumps of several buried at the bottom of raised beds.

I would still want to remove the stumps/roots even though a raised be was to be constructed above as evenually the beds will be a breeding ground for fungi and toadstools which can spread throughout the garden.

Hasn't been a problem for us in over 21 years. Hardwood trees we do remove the stumps of but not conifers.

As the others say, depends what was used to treat the stumps - if it was SBK, then you wait about 2--3 months. Some of the others which are used by professionals can mean waiting a lot longer.

If poison was added only to the stumps, would it also infect the soil around? I agree that it would have been simpler to remove the stumps and roots initially, as they may get in the way with future planting, but if the poison was carefully added, I cannot see the problem with planting in the soil around and between any roots?

Sorry PS: Conifer roots and stumps can take years to rot down, so jimmytheone is right about future problems with fungi, though it may be many years ahead, and not something you may be worried about now! Also, I have personally known some of the spreading low growing conifers to sprout along the root where it is above ground.

Avkq Conifers do not regrow from a cut down stump, I can assure you of this having had several cut down by Bulba over the years in our garden as they got out of hand.

No, conifers do not regrow from a stump, just that some of the spreading low growing ones sprout along the roots (or lower stems just above the ground) which might be more accurate. This is how they spread. We don't know which conifers were cut down, and as all the root has not been taken out these may be showing. I would be interested to know more about stump killer interacting with the soil around, though?

In theory if the holes the stump killer was inserted into were sealed properly there shouldn't be a problem, personally I wouldn't risk it but the only time we have use stump killer was on the remains of a privet hedge on our boundary we wanted shot of. Otherwise we get the root out, thanks to a neighbour with a JCB or bury.

Thank you MG.

With some stump killers, the use is just to spread it over the top and leave it, without making any holes - place soil over that, and there's a strong possibility it will affect the soil around it. SBK, applied to pre drilled holes, then covered and left, with soil put over the top, would have much less impact and, even without covering, wouldn't prevent planting after 2 or 3 months.

Thank you also Bamboo.