can you compost rhododendrons

[chris]

Were you bumping this thread just to start an argument, seeing as it's over 3 months old now?

[Bill HH]

They warn us not to put grass cuttings into compost if its been sprayed with weed killer, so presumably some poisons can remain in compost and thus be damaging to plants. It was a good question.

[Kirk]

Heard the same as Iam, that they excrete a poison into the soil that causes other plants to die, and so they spread as they have no or reduced competition. It may well be not all and only some.

Shredding and composting must stop production of this chemical and what it's life span is after that I have no idea, it may also be relevant to only the roots. I assume that after a length of time you can replant where rhododendrons have been just no idea how long.

This ability they have is why at some places rhododendrons have become invasive to the level of being a pest. They, or some, slowly spread.


A quick search and it seems split whether or not they actually poison the soild by producing a specific chemical.

One option is the leaves fall (they produce lots of leaf fall) and the toxins in these cause problems. The leaves are know to be toxic.

Another concerns the fungi that they need, they enable the one specific type to flourish and none other. Thus when removed the soil is very impoverished and others things cannot grow for an extended period of time.

It certainly appears that when removed not a lot of what we consider useful will flourish, things like broom and gorse seem to eventually get going.

So looks like they manage to change conditions so they are heavily biased to rhododendrons and that afterwards for some time it is not a simple case of dig over and replant with something else and expect success. That change may be from a "poison", toxins from leaf litter or elimination of all but one fungal species.