Possums are the bane of most gardeners, in the leafy inner eastern suburbs of Hawthorn, Kew, Camberwell, Malvern, Toorak, Glen Iris and beyond. I frequently get asked the best way to “deal with them”. Here’s my thoughts on the issue and how best to stop them damaging your garden.
Why do we have a possum problem in Melbourne?
Many of the evergreen, native trees such as Eucalypts, have been removed from the Boroondara and Stonnington area. These trees were replaced with deciduous trees, such as Planes, Oaks, Maples and Ornamental Pears. The proliferation of deciduous trees has caused the problem on two fronts. Firstly, and most importantly, removing most of the native trees has reduced the habitat of the possum’s only natural predator, the owl. With less owls, the possums have bred like rabbits and the population has exploded. To paraphrase Bill Mollison and his slug/duck paradox, “We don’t have a possum problem, we have an owl deficiency”.
Excessive development of the area, has removed the number of trees habitable by owls. At the same time, increasing the size of roof spaces and other nooks and crannies in buildings, have provided perfect nest sites, for many more possums.
Deciduous trees cause another problem, in providing seasonal variation of food for possums. In spring, the trees burst out of their dormancy with a mass of new growth and blossom. This new growth is tender, tasty and very nutritious to the possums. The abundance of new food supports a larger number of possums per area, than the native Eucalypts. The food supply continues into summer, with all of our tasty fruit crops, that the possums happily devour, seemingly, the day before we are about to pick our crops. All of this food allows possums to breed up and occupy smaller and smaller territorial spaces. Suddenly, in autumn, the deciduous trees drop their leaves, and the last 6 months of abundant possum food disappears almost overnight. In autumn and winter we have the problem with too many possums, and not enough food! So the hungry possums begin to explore areas that they haven’t previously. They come down from the trees, in search of those tasty winter veggie seedlings you’ve put in. Passionfruit vines, camellias and any other tender evergreen trees become winter staples for them. Often these evergreen trees succumb to overgrazing by possums in late winter and never recover.
Possum Territorial Behavior
Possums are very territorial creatures. They actively defend their territory from other intruding possums. Understanding this can help to avoid some frustration.
If you trap possums (remember trapping possums IS ILLEGAL), then DO NOT release them at a local park or reserve. Doing so releases the possum into a hostile territory that is already occupied by other possums. The established possums will harass the new “intruder” which usually results in a slow, stressful and cruel death. If you are going to trap possums, then please have the decency to dispatch them quickly and humanely yourself.
By trapping and removing a possum from your property (either by relocating or destroying it) you are creating a territorial vacuum. This vacuum will just reduce the pressure on the population and allow another possum to quickly take its place. It’s a futile task, and only encourages the possums to breed more. I have had several clients proudly tell me that they have trapped up to 100 possums per year. What a waste of time and energy!
Give up on trapping them. You’re not going to make the least bit of difference to the population. Accept the fact that they are here to stay. It’s time to live and work with possums.
Are you planting a lifetime of frustration?
With possums here to stay, it’s worth planning and planting your garden so that you work with them.
To start with, avoid planting deciduous trees in your garden that possums love to eat, but only provide seasonal food. Maples and Silver Birch are two, that possums love to eat and don’t handle their persistent grazing so well. If you really want to grow an ornamental, deciduous tree, try a Manchurian pear or an Oak. Possums love them, but their strong growth seems to support being grazed far more readily, than other varieties. Better still, plant some indigenous Eucalypts and other trees to try and help restore the owl/possum balance.
Don’t plant lots of tasty produce and make it available to tempt hungry possums. Grow food that they don’t like to eat, or when they are not as hungry (spring and summer). Or if you must grow food that they also like to eat, then you need to come up with strategies to protect your food.
Is it really possums doing the damage?
Quite often possums are getting the blame for damage actually caused by rats. Possums don’t usually like citrus leaves or their fruit. Often lemons and other citrus fruit are found with the rind entirely eaten off the fruit, leaving the segmented pith hanging from the tree. This isn’t possums, but rats. Often if you inspect the trunk or main branches of the citrus tree, you’ll see that the rats have also been chewing the bark.
If you’re noticing that only the fruit of your crop is being eaten and the foliage is intact, that’s also probably rats. I’ve seen rats cause a large amount of damage to chillies, broad beans, tomatoes and sweet corn. I’ve seen where they have eaten carrots, leaving a perfect carrot-shaped hole in the ground. I’ve also had rats eat the small broccoli and cauliflower heads as they start to form, and left the rest of the now useless plants.
Before blaming possums and starting World War Three with them, it might be a good idea to try some rat control methods first.
Still convinced you need to do something about the possums? Read on!
Methods for protecting plants and crops from Possums
I’ve tried many methods of protecting my crops from possums. I’ve had mixed success from all of them. What works for one space, doesn’t necessarily work for somewhere else. Usually a combination of some of the methods below works best. To be honest though, if a possum is hungry, there’s not much you can do to stop them.
The most important thing when controlling possums is to avoid them forming damaging feeding habits in the first place. If a possum is used to feeding on your delicious roses or veggies every night then it’s more trouble stopping them, than if they never knew the roses and veggies existed in the first place. Of course, it’s not always possible, but prevention is better than a cure!
Netting and other enclosures
If it’s done well, this can be a great way to prevent possums from damaging your crops. There are two ways to do this
Temporary netting can be draped over fruit trees or hung on temporary framework, made out of star pickets, timber or poly pipe. Just make sure you remove the netting prior to the leaves falling off. Otherwise, it becomes nearly impossible to remove the net, without damaging the tree. Temporary netting is more applicable for keeping birds off trees, than possums.
Permanent netted enclosures are a much better idea. There are many ways to do, this depending on the size of the area. Just remember that possums are great at finding entry through even the smallest of holes. Netted enclosures can also double as a chook or duck run!
If you’re going to rely on netting your fruit trees or using enclosures, make sure you plant dwarf varieties. This means the trees will stay fairly small and netting will be a manageable task.
There are now many variations of possum alarms on the market. We’ve trialed a few and have had mixed success. The only consistency between them, is that all of the alarms come from suppliers, that claim they are the panacea for all possum problems!
Most of the alarms are motion activated and will play a sequence of noises (often high pitched and inaudible to the human ear). Some of them also have flashing strobe lights. Some are battery operated, some are mains powered and some are both.
They can be a great solution for protecting a small area. They are non-invasive, inconspicuous and more subtle, than some of the other control methods listed here.
If you own dogs, then please take their needs into consideration when installing these alarms. We’ve found that some dogs are undisturbed by the high pitched noise, but others are quite upset by it.
We have a few demo models available for our regular clients to loan to trial. We can supply and install new models for you if you decide that they are right for you after the trial.
I haven’t tried these myself, but I recently came across a product called “Pingg-String“. It was being used by a fellow gardener in Northcote and they have had tremendous success with it. It’s not the cheapest solution, or easiest to install, but certainly worth considering. There’s also a solar powered option. Install them along your fence perimeter and keep the possums out for good!
Garlic and Chilli Sprays
There’s a lot of “natural” or “organic” deterrent sprays available commercially. You can also make them yourself. It’s a lot of effort to remember to spray your plants regularly with a garlic and/or chilli concoction. Water from rain or the hose washes it off. I’ve seen entire chilli plants destroyed by possums – chillies and all so I’m not sure why the sprays are going to be effective. It does apparently work for some gardeners, but I’m definitely not convinced on this method.
Blood and Bone
I stumbled across this method several years ago. It works very well for short periods of time. Blood and Bone is essentially ground up dead farm animals. So to possums it smells a lot like death and best avoided. You can scatter the blood and bone about the yard for a very short term solution.
An even better way to use blood and bone is to stuff a handful into an old sock, stocking or piece of fabric. Tie it up in your fruit trees, or wherever you want to deter possums. Simply give the ball a squeeze every week or so to release the aroma. I’ve heard of gardeners using balls of dog hair to deter possums with similar results.
I know, I know, it sounds counterproductive and you have busy lives and possums are pests, etc. etc etc. Personally, I haven’t bothered feeding the local possums, but it makes sense. They are territorial creatures. By feeding a few resident possums you’ll keep them from getting hungry and eating your produce. In return the well-fed possums will maintain their territory for you and keep any of their furry intruding competitors at bay. Just leave your fruit and vegetable scraps in the same place every night and let them do the rest. If you really want to keep your resident possums happy – provide a nest box for them too!
This would be a great way for young children to appreciate nature and share some responsibility for feeding them.
CDs and other shiny things
A few people swear by hanging old CDs or shiny metallic tape around the garden. I wouldn’t rely on this method alone as they quickly get used to it. It’s also a great way to instantly turn your beautiful, aesthetic garden into a tacky mess.
Old stuffed toys with big beady eyes are great for scaring possums. Much cheaper than those owl, or cat shaped silhouettes from the hardware chains and just as (in)effective. The key to using old toys with big beady eyes, is to move them around every night. Like most of these deterrents, if you don’t move them around, the possums soon work out that its nothing to fear and ignore them.
There are two types of garden lights to consider for possum control. Motion activated lights work on a similar principle to the possum alarms above. The possum wanders in front of the light and the light comes on. The possum then gets scared and moves on. You can buy cheap solar powered versions from the large hardware chains.
I’ve had great success with flashing fairy lights. You can buy cheap solar powered versions. Avoid sets that are predictable and just flash on and off constantly. You want the sets that will cycle through a series of different flashing patterns. Hang them in the trees that you want to protect and it seems to keep the possums well away.
Dogs can be a good way to keep possums from the garden. They can be a pain, if they constantly bark at the possums and the possums just stare back at them, from the fence. The right dog can be an effective possum controller. I’ve noticed some of my clients have erected new pool fences, that have restricted the dog’s access of the whole yard. This has resulted in possums attacking the veggie patch where they hadn’t previously done so.
Possums don’t like to wander across open ground. In fact they don’t like to come down to ground level at all. Quite often you can limit their access to certain spaces, by removing a single tree branch, or cutting vegetation back from the fence line. This will only work in a small number of cases, but can be very effective.
Things that don’t work to deter possums:
Don’t waste your time or money on the following:
- Spikes for putting along fences. Fences are better known as possum highways. The idea is that you’ll limit their access. Possums happily climb over roses and other prickly plants. They are not the least bit disturbed by the plastic spikes.
- Cat and owl silhouettes: only work for a very short time and need to be moved regularly. Save your money and use an old stuffed toy with big beady eyes instead.
- Possum traps: it’s a futile activity!
Got your own method for keeping possums from eating plants?
If so, please let us know in the comments section. We’d all be most grateful!