I first noticed Australian Mint Bush in our greenhouses two springs ago. If I remember correctly it was very early spring, maybe late March or April. I was walking through the herb greenhouses to get to a greenhouse on the back of the property and noticed a lilac haze that stopped me in my tracks.
Native to Australia and Tasmania, prostranthera rotundifolia has tiny, ovate, very fragrant, evergreen leaves. In our greenhouses they tend to take on a standardized look very quickly from stem cuttings and lend themselves very well to that look. I have also seen them closely sheared much like a boxwood to great advantage also. With its lovely fragrance what a sweet chore shearing them would be. The Australian aborigines used the leaves in an infusion for relief of headaches and colds. The small mint flavored leaves are also used for culinary purposes in place of thyme and for potpourris.
A small plant transplanted that spring into a large pot on my back deck soon grew to about five feet. Since we show it being hardy to zone 9 I brought the huge pot inside an unheated back room to winter over. It survived just fine though it did get a bit leggy that winter. I was disappointed the following spring when it failed to bloom.
While bringing tender plants in this fall I decided it really wasn't worth the room in the small area I use to overwinter plants so I placed the pot up against the side of my house in a southeastern exposure thinking I would pull the dead plant out and plant something else in the large pot this spring. While working outside this past weekend I was very pleased to discover that it has survived some very cold nights into the teens and still remains green. If it survives the rest of the winter and blooms this spring I may very well rethink its worthiness and plant a couple more. For this reason prostanthera rotundifolia is my plant of the moment.