dymondia waterlogged by winter rains.
In Oct. 2009 I planted dymondia next to concrete walkway in my courtyard garden which gets brutally hot sun from spring to early fall, shade (from nearby wall) when sun's path sinks during 2 1/2 mo. in winter. Soil is clay, top 6 in. was amended w/gypsum and topsoil. As plants became established in winter 09-10, they spread steadily, and with judicious watering in spring-summer 2010 I got a nearly full carpet. Since Oct. (2010) we've had 2-3 spells of daily rain for 3 days - 1 wk at a time. I'm experiencing leaf die-off in ugly patches here and there. Leaves turn mushy gray pulp, I pick them off carefully, and during sunny periods I see little green shoots here and there, the plants are trying to fight back. During the period I have edged the area carefully and the roots appear strong, just the tops seem to be getting creamed so far. MY QUESTIONS:
1. We have another 2 months at least of rainy season, what's this going to do to the root system?
2. If roots survive, will the plants' leaves spring back after winter or will coverage be reduced for a long time?
3. Seems like the rainfall is dumping more water than the roots can absorb. The achilleas, strawberries, lavenders, gauras, etc in immediate vicinity are doing just fine in the same amended soil. Now that the dymondia is in, what can I do to prevent a recurrence short of digging the whole area up and starting over?
4. If I have to indeed "destroy in order to save", what sort of soil amendment procedure would you recommend?