Top 10 Plants That Date Your Garden and Create Ecological Dead Zones
Agapanthus (Agapanthus orientalis)
Yuccas (Yucca species)
Canary Island Date Palm (Phoenix canariensis)
Box Hedges (Buxus species)
Nandina or Sacred Bamboo (Nandina domestica)
Gazania flowers (Gazania rigens)
Dietes or Butterfly Plant (Dietes gradifolia)
Ornamental Pears (Pyrus species)
Diosma (Coleonema species)
Pittosporum hedges or screens (Pittosporum tenuifolium and Pittosporum undulatum)
Left: Environmental weed Agapanthus (Agapanthus orientalis) . Right: Nodding Blue Lily (Stypandra glauca), a great native alternative to Agapanthus. With a clumping habit and loads of big blue flowers like Agapanthus, this hardy plant is a stunner in the garden. Image by Melissa Stagg
In my line of work, I’m often asked to help people update their dated and tired looking gardens. I also get asked about how to attract more birds and wildlife into people’s day-to-day lives. I spend every day looking at gardens and plants, and thinking about what role they play in their landscape. I’m always taking note of which plants are brimming with life, bringing in native birds, pollinators and animals, and which ones support as much life as a block of concrete in a garden.
Another aspect I’m always considering, is which plants are common garden escapees, that become problematic weeds in our native environment. Most people have no idea of the countless people-hours and tax payer dollars that are put into controlling garden escapee weeds in our native environments (bushland, wetlands, creeklines, grasslands etc.) every year. Although some plants seem like great options for your garden, because they are great survivors and just can’t be killed (even by the most gardening illiterate person), these exact survival traits are what makes them such a big problem in our native environment. Once they escape, they overrun our native environments, driving out our indigenous plants, and distorting the balance of the local ecology. They are a biodiversity disaster; creating ecological dead zones that don’t support our precious and unique Australian birds, animals and pollinators. This is also why you shouldn’t dump your garden wast in your local bushland (or creekline etc.), because some of it can survive and grow out of control to become a weed problem. Many of these plants are actually banned from use in gardens, and aren’t supposed to be sold in nurseries. Further information on environmental weeds (in Victoria), and a list of species to avoid can be found here https://www.environment.vic.gov.au/invasive-plants-and-animals/weed-risk-ratings
For every weedy exotic plant you have in your garden, there is a native and ecologically sound alternative that will give your garden an updated and timeless look.
In addition to being ecological disasters, these plants also really date the look of a garden, and can even look quite daggy. Many of them were popular choices for planting in public places in past decades, and often are still hanging around there to this day, looking tired and daggy. Many were commonly used in the 80’s and 90’s for carparks and fast food drive-throughs, and a result they give a garden the daggy look and feel of a KFC drive-through. Now, I don’t know about you, but this isn’t the look I’m going for when designing a garden. So if you have these plants in your garden, why not do our native critters a favour and replace them with some beautiful native alternative species.
The Top 10 and some Native Alternatives:
Agapanthus (Agapanthus orientalis): Nodding Blue Lilies (Stypandra glauca) or Flax-lilies (Dianella species) have a clumping form and masses of blue flowers like Agapanthus.
Yuccas (Yucca species): Grass Trees (Xanthorrhoea species), Cycads (Cycad species) and Cabbage Fan Palms (Livistona australis) are sculptural and hardy like Yuccas.
Canary Island Date-palms (Phoenix canariensis): Cabbage Fan Palms (Livistona australis) are also a good alternative here, but why not consider updating from the ‘tropical look’.
Box Hedges (Buxus species): Correas (Correa species) and Hop-bushes (Dodonaea species) are shrubs that can be pruned and clipped like a Box Hedge. Why not consider looser, more flowing forms, to update the look of a hedge.
Nandina or Sacred Bamboo (Nandina domestica): There are a wide range of Agonis varieties (Agonis species) available in nurseries that are hardy and come in a range of different foliage colours like Nandina.
Gazania flowers (Gazania rigens): A wide range of native wildflowers are hardy and will give you a showy and colourful ground cover like Gazanias do.
Dietes or Butterfly Plant (Dietes gradifolia): Native White Iris or Butterfly Flag (Diplarrena moraea), Lomandra (Lomandra species) and Flax-lilies (Dianalla species) are hardy and will give the same strappy appearance as Dietes.
Ornamental Pears (Pyrus species): These are often chosen for their convenient small size for a home garden. Green Mallees (Eucalyptus viridis) are a small and hardy tree, with a nice form and beautiful delicate green foliage. They also get loaded with flowers in Winter, that will bring in a wide range of native birds, pollinators and animals.
Diosma (Coleonema species): Common Fringe-myrtle (Calytrix tetragona) has a dense form, fine foliage, masses of pink flowers and is hardy, just like Diosma.
Pittosporum hedges or screens (Pittosporum tenuifolium and Pittosporum undulatum): Weeping Pittosporum (Pittosporum angustifolium) is an alternative species of Pittosporum for a hedge or screen. It gets wonderfully eye catching orange seed pods, creating some colour and interest in the garden. Careful when buying this species, as the weedy Sweet Pittosporum (Pittosporum undulatum) is sometimes mislabeled as Pittorsporum angustifolium. This error can even be found on the South Australian government’s weed advise website. An easy way to tell the difference is the foliage. Weeping Pittosporum as long narrow ‘weeping’ leaves, whereas Sweet Pittosporum has broad leaves.
Be sure to remember any plant has the potential to become a weed when planted in the wrong place. Always check with your state or territory’s government advise to find out what the weeds are in your area.
Article by Melissa Stagg - Principal Landscape Architect