NON WEEDS FOR YOUR GARDEN

Published in The Nimbin Good Times, July 2005

Home

 David McMinn


Regular NGT readers will be fully aware of the my stance on weeds, after reading my articles on this topic over the past year. Rather than going through a list of weedy plants to avoid, a coverage is given of the numerous exotic plants that you may safely use in your garden without fear of them spreading through your garden and into the local environment. I am not against people planting exotics, so long as they are non weedy and are not planted in local forests.

The following exotic species have a proven track record of being non-weedy, with limited potential to go feral. Why plant weeds, when you may select from so many attractive non weedy natives and exotics? Why give yourself and the environment a weed problem when it is entirely unnecessary? This list illustrates that you have many alternatives in your garden choices. When you plant a new species/variety in your garden, ask your self four questions.

Can it produce prolific quantities of viable seed in our area?

Can its seed be efficiently dispersed by wind, birds or wildlife?

Can the plant spread easily by vegetative means? (ie: bits being swept downstream during floods or spread by humans in garden waste.)

Does the plant grow rampantly in our region?

If the answer is yes to any of these, then be cautious about planting that species. A good approach is an internet search to see if it is a weed overseas or in other areas around Australia. Alternatively, query your friends on their experiences with the particular species and how it fared in their gardens. Even after these precautions have been taken, problems may still arise. If so, get rid of the plants quickly. A few specimens are easy to eliminate. Once they have gotten out of control, you will have a lot of extra weeding or you will just have to live with the infestation.

There are ways around the problem of weeds in your garden.

*      Plant seedless varieties of weed species if they are available. The best example is the seedless form of Orange Jessamine (Murraya paniculata). People can plant this variety and still enjoy the perfumed flowers without creating a weed problem.

*      Every year, strip the unripe seeds from any potential weedy tree/shrub, thereby preventing the species from spreading. Obviously, this approach is suitable for only smaller growing species. 

*      For species with male and female flowers on separate plants, only use male specimens in the garden, so seeds are never produced to create problems. Paper Mulberry (Brousonetia papyrifera) has the potential to be the weed from hell in our area - from my personal experience. I purchased two plants at The Channon market - unfortunately they turned out to be a male and a female, thereby producing viable seed and creating a weed problem around our Blue Knob farm. All the large trees have been poisoned, but seedlings keep popping up and are difficult to control. Insightfully, the ancient Polynesians only took male plants on their voyages to establish new settlements in the Pacific, thereby preventing Paper Mulberry from becoming an invasive weed.

A major obstacle is that a plant is only declared noxious after it has become a problem. Being classified as noxious means that weed inspectors can force land owners to do something about the spread of the species on their properties. It would be far more sensible if the authorities were proactive. Plants should be thoroughly vetted before they are sold to an unsuspecting public. Gardeners and land holders should only be able to plant species that are deemed to have limited or no weed potential. Alas,  with Paper Mulberry, no government bodies will help my control efforts at Blue Knob unless it is declared noxious. By the time it is declared noxious it would be too late, as it would be out of control and wreaking environmental havoc. Unbelievably stupid.  

The following listing is by no means comprehensive and it would be appreciated if people emailed their suggestions on other non weeds so that the listing may be expanded upon - tfm56@yahoo.com. This article can be downloaded from The Nimbin Plant Selection Guide (www.davidmcminn.com/ngc). Corrections are most appreciated. People may select from an enormous range of native and exotic plants to create a beautiful garden and still remain environmentally responsible.

Azalea is not a weed problem in our area. However, people living in rural areas should be aware that these plants are apparently poisonous for the local wallaby population and should be avoided in such situations.
Bamboo species. Clumping bamboos are promoted as a non invasive alternative to the rampant running bamboos. However, clumping bamboos do pose a serious maintenance problem. Unless you are going to harvest the shoots and/or culms regularly, do not plant large clumping bamboos. They still spread outwards and ultimately become huge and indestructible. I have been trying to kill one large clump on our farm by removing all new shoots. The aim was to exhaust the clump EVENTUALLY. After 5 years, it is still surviving, but very much reduced in size. (Poisoning was never an option.) In Asia, bamboos have a massive flowering every so many decades or even centuries. With this abundance of seed, rat plagues become a major health and economic concern. How a bamboo flowering will impact upon the Australian environment remains unknown, as it has never happened before.
Boysenberry & Loganberry. These berry cultivars are hybrids derived from the common Blackberry, which is a highly noxious pest in southern Australia. However, they are both non weeds, as they produce infertile seed and thus may safely be planted in your garden.
Bromeliads. Generally these attractive epiphytic plants are a safe, non weedy option to grow in a garden. The notable exception is perhaps Spanish Moss. This species hangs down from tree branches in an attractive shawl like mat. It has potential to cause problems, as it can spread from tree to tree. It is in the process of engulfing the beautiful Bunya Pine in the grounds of the Nimbin Catholic Church. In its native southern USA, the weight of this plant may result in limb breakage, especially in heavy rains and/or high winds.
Browallia species. Perennial shrub with pretty orange - yellow flowers, which may safely be planted in gardens.
Camellia cultivars. Camellias do not present a weed problem in our region. These are slow growing, small trees native to eastern and southern Asia, which are widely cultivated for their beautiful flowers.
Cycads. The weed potential of this group of plants is zero, as the plants are usually very slow growing. A specific beetle species is  also required to pollinate each species of cycad. These are lacking in Australia for exotic species, so they will rarely produce viable seed. Any plants that did go feral would be quickly ripped off by plant poachers, wanting to make a quick buck. Large cycads are highly prized and very valuable.
Datura species pose a limited weed threat in our area.
Frangipani cultivars have been grown in Australia for over 100 years and have never presented a weed problem.
Gardenia species & cultivars. Exotic Gardenias species do not pose a difficulty. You may also consider the native Gardenia or Rhandia species as alternatives.
Hibiscus cultivars. These very attractive species have limited weed potential in the Northern Rivers. A few species grow rampantly, but they do not set seed or spread extensively. 
Magnolia species & cultivars. This genus includes many beautiful plants, including evergreen and winter deciduous species from Asia and North America. None are known to cause a weed problem and are well worthwhile growing in local gardens.
Orchids. Many orchid cultivars are so heavily hybridised that they are infertile or have poor fertility. Some exotic species may present a problem, but no web references could be sourced to support this possibility.
Palms. Most palm species do not present a weed problem. They are usually slow growing (eg: Rhapis, Howeas, etc) and they often only have a single trunk - one swipe with a chain saw will kill the tree, with some species rewarding you with delicious heart of palm salad. However, there are exceptions and a few species of Chamadorea, Phoenix and Syragrus have serious weed potential.
Rose cultivars. Cultivated roses are non weedy and it can be more of a problem to get them to grow well in our warm humid climate. Many varieties are prone to fungal attack so it is best only to plant varieties with good disease resistance. Importantly, some Rosa species can escape from gardens, causing localised weed problems (eg: along Blue Knob Rd).
Port Wine Magnolia is a small, slow growing evergreen tree usually to 2m - 3m. Its glossy leaves are dense giving the plant a compact shape.  The cream and red-brown flowers are produced in December and are heavily fruit scented. 
Cuban Royal Palm (Roystonea regia). In frost free areas, plant this as an alternative to the weedy Cocos Palm (Syagrus romanzoffianum). Royal Palms are longer lived (200 years) and more aesthetically pleasing with limited weed potential. Even better select the local Bangalow Palm (Archontophoenix cunninghamii).
Strelitzia species. Bird of Paradise and Giant Bird of Paradise are very attractive evergreen perennials and have been grown in our area for decades. They are very unlikely to become weedy.