We have our share of invasive Scotch broom (Cytisus scoparius) on our new property and we've been trying to figure out how to best make use of all that organic matter to try and bring it under a semblance of control. We finally got a whole whack-a-do chipped with the idea of adding it to compost as woody matter to increase the fungal content, and also as garden mulch around plants. Then someone went and said that it secretes a tar that is toxic to other plants. I have never heard of this. From my research I've only found reference to this once, here: The drive to sweep away scotch broom - Arrow Lakes News and I'm not sure if this is reliable, or if they're maybe mistaking Scotch broom for something else. I turn to you, Knowledgeable Ones, for any insights you might have before I make a terrible mistake and ruin both my compost and garden with potentially harmful plant matter.
There is no mention on the ckiss.ca site that a tar is produced. However, Scots broom is known for having seeds that can persist in the soil for over 40 years, so attempting to make compost out of plants and then planting using that compost is likely just a means of spreading it. From: Scotch broom - CKISS - Central Kootenay Invasive Species Society
I had not considered contacting CKISS directly, but you've inspired me to do so; thank you. We made sure to only harvest broom that was in the flowering stage and free of seeds, which will hopefully prevent us contributing to its spread.
Just to follow up, I did write to the organization quoted in the article I posted about the 'toxic tar'. The response seems woolly to me. They replied: "I believe that the tar that they are referring to is the oil in the stems and leaves, but I don't have a reference for that. Perhaps that was an anecdotal comment." Unless anyone else has any insights which they choose to post here, I will continue with my experiment and apply the chips. I'll try to remember to report back, just in case anyone else comes across this kind of question. If you already use broom chips successfully, please let me know. Thank you!
Personally I would incinerate before using the chips if there is any question as to seed pods being present.
I would like to add that Scotch broom should also never be burned. When I was a young pro golfer (70's), I would tour the country and often speak to greenkeepers for tips about the grass etc etc etc. I remember on one course them burning the invasive Scotch broom after being told to by an 'expert' lol. The result was an increase of this invasive plant, as fire explodes the seed pods scattering the seed far and wide. A lesson very much learnt by the greenkeepers digging this out for many years after.
I haven't noticed any allelopathic effect of the Cytisus scoparius. It is invasive in the forests around my home, but not very aggressive. Often winter frosts kill these bushes here, but other plants happily grow on remains of the C. scoparius.
The PH and temperature may play a part where you live Sulev regarding growing conditions. Nice to hear from you btw, warming up there ??
Hi, @Acerholic It is pretty warm here now, daily highs have been around +20°C...+25°C for several weeks already, latest few days even closer to +30°C, and even nighttime lows are raised above +10°C recently. And the forecast is the same. They call it heat wave :) Truth is that we are lacking some rain. Cucumbers and melons are starting to bloom. Luudpõõsas (Estonian name for Cytisus scoparius, to avoid offending anyone) finished blooming a week or two ago. This year they bloomed especially abundant, because we had mildest winter of my lifetime. They are pretty beautiful when blooming. Unfortunately this won't last long.
Request: the spelling 'scot*h' in this context is considered very offensive by a lot of people in Scotland; please don't use it. The correct spelling is 'Scots' or 'Scottish'.
When I say incinerate I don't mean to just burn...either in piles or in the field. IF there are seed pods it must be rendered to ash. Otherwise chip away before it flowers and goes to seed. Very invasive and prolific here in B.C. I've had lots of experience with this on a large scale.