Cover Up!

Brian Walters

Useful things, ground covers, don't you think?

They can be used to give quick cover in a newly established garden; they can fill-in under larger shrubs and trees in older gardens to reduce the stark "bare earth" appearance; they can be used effectively to spill over regularly structured walls so helping to create the less formal appearance that is strived for with bush gardens; they can look wonderful spilling down embankments...some will even help to stabilise slopes.

Some ground covers can be very effective in areas where taller plants would interfere with such mundane objects as rotary clothes lines.....and still others make superb subjects for hanging baskets.

So, let's have a look at some of the applications for native ground covers in more detail. Later on there's a list of 30 of the best ones. You'll surely find a few among them which can be put to good use in your own garden.

Vigorous covers

The main advantage of vigorous ground covers is, naturally enough, their vigour. The disadvantage is that they rarely stop when the required area has been covered...I swear, some of them grow while you watch!

It's a similar problem to the small tree syndrome...you know, everyone wants a tree which will grow to 5 or 6 metres in two years and stay there.

Unfortunately, trees that grow that quickly usually end up as forest giants and vigorous ground covers that quickly reach 2 metres diameter have their sights set firmly on 4 to 5 metres or more.

If you can accept that you'll need to get "stuck in" with the secateurs or pruning shears once or twice a year then there are several vigorous ground covers that will do a superb job.

Principal among these are some of the Grevilleas, a few of which are listed in the table. One that has been around for a while is Grevillea "Poorinda Royal Mantle"; it is adaptable to many areas and to many soil types and remains one of the very best. Then there's G. "Bronze Rambler", which is hard to beat. Both of these have flowers arranged in "toothbrush" spikes, the former in a bright red and the latter in a maroon.

Moderately vigorous ground covers

This is a much bigger and more useful category. The plants in this group might take an extra season or two to cover the required area but will normally need less maintenance to keep them under control.

This group includes both dense covers (which totally obscure the ground) and trailing types (which send out long branches in several directions). The latter type may be a bit sparse, and the term "ground cover" may be a bit of a misnomer when applied to them, but they look particularly effective spilling over retaining walls or just trailing under other shrubs.

This moderately vigorous group includes some of the most interesting plants of all. The prostrate banksias and acacias (wattles) listed in the table may be a little difficult to obtain, but they are real attention grabbers. For a really weird effect, try growing these next to the normal, upright forms of the same species!

The banksias are fairly dense in habit while the acacias are more open. Other very adaptable, open species are the prostrate forms and hybrids of Grevillea juniperina, such as 'Molonglo' and "Carpet Queen".

Some groundcovers worth trying
Acacia cultriformis 'Austraflora Cascade'	Banksia serrata Prostrate form	Darwinia taxifolia subsp.macrolaena	Dampiera stricta

Grevillea 'Molonglo'

Hibbertia diffusa

Pelargonium rodneyanum

Viola banksii

Photos: Brian Walters

Ground covers with some height

Ground covers don't need to be totally prostrate.

A few examples reach a half to one metre in height and develop a dense "cascading" habit. These are good foreground plants as they can be used to camouflage spindly growth that might occur with some taller plants.

One of the best of this group is Grevillea "Austraflora Old Gold", a cultivar with divided, slightly prickly leaves and beautiful honey/gold flowers for many months. It reaches a bit over half a metre high and spreads to about 1.5 metres. Unfortunately it seems to have gone out of favour a bit and can be hard to find.

Another useful Grevillea is the red, prostrate form of G.juniperina. Unlike the yellow forms, the "prostrate" name is definitely a misnomer. It is similar in habit to "Old Gold".

Compact ground covers

Plants in this group are strictly for show.

Generally they are small, slow-growing clumps which can look great in a rockery. I often use them as "sacrificial offerings" ...you know, just plonk them in as "fillers" between other shrubs in a new garden. Eventually the larger plants will overwhelm the smaller ones, but by then it really doesn't matter.

Some of the small hibbertias are excellent...the bright yellow flowers put on a spectacular display. Hibbertia pedunculata and H.diffusa are two of my favorites. H.pedunculata is great value too! It tends to form roots where the branches touch the ground (ie. it self layers). Segments with roots attached can be potted up to form new plants with almost ridiculous ease!...great for those whose fingers lack a green tinge.

Another favorite is Dampiera stricta. Like a number of dampieras, this is a suckering species and it will not be confined to the place where it is planted. But it's certainly not invasive and could never be regarded as a pest. The blue flowers look superb against the greyish-green foliage. If you can't get that particular species, virtually any other Dampiera is worth a patch of dirt.

Several of these compact growers look wonderful in hanging baskets. Varieties with loose, trailing stems are best as they tend to spill over the sides of the basket and display their flowers effectively. The scaevolas ("fan flowers") and some of the dampieras are great.

Ground covers for shady areas

Now for the problem area! In this situation it's often necessary to experiment and you shouldn't be too concerned about floral spectaculars! There are few flowering plants that produce their best display in full shade...partial shade, yes; full shade, no.

But before you call for the concrete mixer, check out the area thoroughly... most people only have a vague idea of how much sun the various parts of their gardens receive. It mightn't be as shady as you think!

Moist shade is less of a problem than dry shade because there are a variety of ferns which can do the job. Among the flowering plants, the native violets are hard to beat. The most commonly available is Viola banksii (often sold, incorrectly as V.hederacea, a species which is not commonly available). V.banksii spreads by stolons and the blue and white flowers look particularly attractive. It tends to die off in exytended dry periods (unless watered) but will reappear after good rains.

A similar plant to the viola is Lobelia trigonocaulis (sorry about the name!). It too has blue flowers but it will do well in both moist and dry conditions. I have used it effectively as a scrambler beneath other shrubs.

A final word

There is an enormous range of ground covers suitable for any conceivable purpose. A visit to one of the specialist native nurseries will reveal far more varieties than are listed in the following table.

In creating a garden, any garden, it's always good to include elements that add interest. All too often we are seduced by spectacular flowers and give little or no consideration to growth habits. A garden should be able to maintain interest even in seasons when flowers are less prolific. Selection of plants on the basis of growth habit and foliage (as well as for floral characteristics) helps retain long term interest in the garden.

Ground covers add that extra dimension to a garden with very little conscious effort on the part of the gardener. They really are ridiculously under-utilized.

Based on an article published in the October/December 1990 issue of "Gardens and Backyards" magazine.

Australian Plants online - 2007
Association of Societies for Growing Australian Plants