Anita Morton - Growing Gardens
Living mulch for difficult gardens
It doesnt take long for the garden to dry out when it hasnt rained for a while. I hope you have all your perennials and shrubs well mulched it really is the answer for moisture retention, weed control and protection of the soil from erosion by heavy rain. Unfortunately, that still leaves areas such as slopes and retaining walls where mulching is not practical.
Sunny banks and retaining walls benefit greatly from being planted up with hardy prostrate plants their leaves shade the ground, and act as living mulch. There is any number of prostrate grevilleas, banksias and herbs like rosemary that will do the job, as well as providing bird and butterfly attracting flowers. The only problem is that few have sufficiently dense foliage to suppress weeds. Plant through weed mat and/or put down a layer of large pebbles as a safeguard.
A slope in dry shade is the toughest garden site to fill. There is one tough little bulbous plant in our garden that has managed to shrug off dry conditions and permanent root competition with aplomb. It grows thickly and chokes out most weeds, and that is its saving grace, for it is almost completely undistinguished. Ledebouria petiolata is its name I dont think theres a common one in use, though the related (and more attractive) L. socialis and L. violacea are called the silver and violet quill respectively.
There really is no reason to know about L. petiolata I thought for ages that it was probably some rather boring relative of Lachenalia. It has quite nice blotchy foliage, and does flower in a mingy, colourless way, but if youre looking for a garden star, this is not it. What it does do, and do remarkably well, is thrive and suppress weeds in that difficult dry shady spot where nothing wants to grow.