Posted: 14/05/2013 at 10:42
I gather that the reason you want to add soil to the border is in order to reduce the size of the border and turn it into lawn, the same level as the existing lawn.
It seems a shame to kill off the plants, couldn't you give them away or sell them for charity.
If you really need the front garden to be easier to maintain and you want to reduces the size of the beds then you will need to remove the plants, either how I've said above or by using glyphosate weed killer which inactivates in the ground so you can replant afterwards. Then you need topsoil, which your GC may sell, but you will probably need it delivered as it will be very heavy. Not just compost, too light.
The reduced in size border will need digging over, fertiliser, compost or manure added. Then cover with a permeable fabric. Cut holes in it and plant low growing bushy shrubs, such as lavender, spirea Anthony Waterer or one of the golden ones, choisya Aztec Pearl, caryopteris (blue flowers, gold or green leaves), santolina. Then cover it all with a thick mulch of bark chippings. I have done it myself with a shrub bed that I did about 6 years ago and I have hardly had to weed at all and the bark has stayed put. There haven't been any pests and the shrubs are healthy.
Once you have added the top soil and trodden it down and raked it (so it is the same level as the lawn, you may need professionel help or a son, nephew, friend), then scatter grass seed and rake in a bit and keep damp until established. Grass seed normally grows pretty well.
Verdun is a really good gardener with a high maintenance garden, but I think, from what you say you need a real solution as you will not be able to cope with a lot of maintenance.