Last week's local native plant was one of the biggest around, the Blackbutt (Eucalyptus pilularis). To add balance, this week's plant is a very small and delicate groundcover that won't cause any problems or create any alarm.

It can turn up uninvited in gardens and twine in among lawn, other ground-covers and even low shrubs, but it is often overlooked because when it's not in flower there just isn't that much to see.

Look closely, however, and you will see that the small white flowers have the shape of a Lobelia. And, yes, it's a Lobelia! Lobelia purpurascens to be precise, though the common names are easier to remember: White Root (for – you guessed it – the colour of the small, sinuous roots) or Purplish Lobelia, which goes to the purplish tinge the centre of the flowers have, if you look really, really, really closely.   

Lobelia is a familiar plant name for many gardeners. The electric blue of some of the Lobelia cultivars sold as annuals is pretty unforgettable. This species is, it must be said, much less showy.

But it has many advantages over the commercial Lobelias. It is perennial rather than annual, so will hold on year after year: you don't need to buy new plants each spring.

It is a local native, not an exotic and not a cultivar, so it will make a better contribution to supporting local bees, butterflies and other insects that have co-evolved with it.  

And it is drought-tolerant, though not in a conventional sense of looking exactly the same all the time: it copes with dry conditions by producing fewer above-ground stems and flowers, so that in an El Niño period it may be all but invisible. But in a La Niña as we've had recently, it will come out of itself and produce abundant foliage and numerous flowers, and look absolutely gorgeous.

The number one query I've had in the last two or three months has been a request to identify a small plant in someone's garden that turns out to be Whiteroot. And I'm just thrilled to be able to identify it as a local to this area. Once you know it's a local native you can take a sigh of relief and stop worrying about how to eradicate it! You can instead turn to seeing what interesting critters come to visit.

Emma Rooksby is the co-ordinator of the Growing Illawarra Natives website