That looks absolutely stunning! I suspect it is simply a consequence of aging. The plant creates hummocks and something similar to thatch in lawns may be happening; an increase in organic material that then makes growth conditions less favourable. I've seen it in many times in other hummocky low-growing plants. It is very hard to keep a vista such as this in never-changing condition. I'm not an expert, I'm just thinking out loud and hopefully for you this analysis is wrong. Nature usually needs change though. Clump-forming plants tend to become woody and/or lose vigour in the centre. Lawns need constant maintenance, and so on.
Mine look like that after frost. They soon recover. Do you trim them?
Propagation is absolutely no problem. It just seeds about; can't stop it. Clear it and it will be back. "Curse of Corsica" is not so named without reason.
Try just digging up one of the offending patches and having a look.
The National Trust have a Japanese garden at Kingston Lacy with Soleirolia, their head gardener may have an answer.
I grow in pots as a ball on spagnum moss. I keep a number standing permanently in water. I rotate: week in the house, 3 weeks in a cold grennhouse.
Magificent effect though. Well done.
location: Surrey Hills, England, ex-woodland acidic sand. "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
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I'm not an expert, I'm just thinking out loud and hopefully for you this analysis is wrong. Nature usually needs change though. Clump-forming plants tend to become woody and/or lose vigour in the centre. Lawns need constant maintenance, and so on.
Propagation is absolutely no problem. It just seeds about; can't stop it. Clear it and it will be back. "Curse of Corsica" is not so named without reason.
Try just digging up one of the offending patches and having a look.
The National Trust have a Japanese garden at Kingston Lacy with Soleirolia, their head gardener may have an answer.
I grow in pots as a ball on spagnum moss. I keep a number standing permanently in water. I rotate: week in the house, 3 weeks in a cold grennhouse.
Magificent effect though. Well done.
"Have nothing in your garden that you don't know to be useful, or believe to be beautiful."