Recommendations for removing a plant from a perennial border

Question

I'd love some recommendation on the best way to remove Lysimachia nummularia 'Aurea' from a perennial border. A little background: The border never really goes fully dormant, and is layered with many plants, including several layers of bulbs. Because of this, and because it's a fairly steep bed, we don't mulch much. Soil is mostly clay with a thin layer of better soil on top. The bed is about 1000 sq ft. I can take some photos tomorrow when I'm at work if people think that would help.

What I've thought about:

• Sheet mulching
• Hand digging
• Dig everything out and start over

I'm worried the sheet mulching would prevent the bulbs from coming up, but perhaps if I start in early November, the newspaper would be decomposed enough by mid-January to let the first crocus bulbs poke through. I suspect the daffodils can get though. I suspect I'd need almost 2 years to make sure I get everything out of the bed before I did a complete renovation. To make matters worth, I don't really have a nursery location to store stuff.

Update

Finally getting around to getting photos posted, it's been a busy week.

• What started out a cute edging along the steps has really started to take over. You can't see it here, but it is now covering about 80% of the bed.

• It's starting to out compete other wanted plants. Here, this used to be a solid mass of Sedum 'Autumn Joy' maybe five years ago. It not only gets in the crown, but it scampers up the stalks, shading them out.

• It's difficult to see here, but about 4 months ago I pulled all the creeping Jenny off to the ground. Now it's almost a foot thick, and climbing all over the heathers.

Answer 1

A systemic weedkiller or just digging out would be the best way, don't use newspaper- often has the result of attracting unwanted pests like slugs to scene and doesn't really break down as fast as one hopes- it forms a static layer that just stays there allowing very little through it. If the bed is as large as you say it is then I would break the area up into smaller chunks for ease- a thousand square feet is no small job for one person. for record taking I would refer to photos taken every month to help you plan out planting, I often forget where I exactly planted bulbs etc especially in the dormant season- however new thinking says one can actually do it at any time of year now? the results are not in so don't do anything silly right now. An Irish garden designer (I saw on telly) would often split up herbaceous plants right now for propagation- but like you said you don't have the space. the steepness to site might cause a few problems- although one could terrace the site or use wire netting to stabilize the surface soil or possibly use large stones, logs or sunken preplanted pots or even plants with extensive root systems. Perhaps some photos of the site might help generate ideas.
Looking at the photos, the indicator plants are telling me its a slightly acidic clay soil, the creeping jenny isn't really stabilising the soil much only stopping surface erosion and more likely the heather is doing the main job, some nice stuff in there, sedums and ox eyed daisies(dense fibrous surface rooting stuff) , plus some irises dotted around, difficult to tell how steep it is by the photos. You could try some larger stuff, perhaps some fairly large evergreen acid lovers(rhody's, camellia, arbutus, tree heather?)that will stabilise the soil and add interest during the winter, and I would just clear out anything that looks tired and dead- just do it slowly, section by section, methodically working your way across, perhaps having a rethink if terracing it is even possible and what your budget is? The soil looks fairly poor so adding something like compost or mulch as go might be a good idea and the herbaceous stuff could possibly be split and divided to either spread or renew older clumps by removing the older stuff from the centers and replanted the outer stuff like new plants again in odd numbers clumps( don't know why that works but it looks more natural) I'd also wait until the weather is more wet, those pictures make it look very dry nothing likes being moved when very dry indeed and watering on a slope causes problems...again I think you need to do research into other peoples gardens and see how they have coped and how long it took them to complete their projects. make take a while...