Q: "Hi Bob, how can I deter possums from eating my rose buds, or new growth on rose plants. It seems to happen only to the roses that are around a metal or concrete fence where they can apparently support themselves and chew away happily. Have tried certain sprays etc but to no avail. Pleeeeese help!" Margaret - Coorparoo and Ruth – Toowong
A: Sweet little blighters…but they can be destructive little buggers too, can’t they?
Well…there ARE a few techniques that can help gardeners. Here are some very practical methods that have been tried, and all of them have been successful.
Caging plants
A very effective method is to surround plants with a physical barrier to prevent the possums getting at the plants.
Your cages may be simple little contraptions made of chicken wire or other material which would protect a single plant or a collection of plants, or even an entire bed. In the City Botanic Gardens, we used to buy hundreds of potted annuals already in bloom for displays. We had to hold them in our nursery for a few days before we set up the display, and the City Botanic Gardens has hundreds of possums. It was embarrassing to find that possums had decimated our plants. I came up with large cages to protect our plants, and solved the problem.
Tight wire
It happens, at times, that the ONLY way possums can get to a particular set of plants is by traversing the top of a fence or by using a particular ‘pathway’. OR, they may have a habitual route that they use. (Margaret of Cooparoo – is this YOUR problem?). If you can block this route by one means or another the problem is often solved. They sometimes do not like running along the ground, possibly due to the presence of dogs or cats.
My son was having problems with pigeons sitting along the top of his fence . He was not impressed with the white mosaic-type design created on his side of the fence. His neighbour was feeding the pigeons and they used the fence as a convenient roost. I strung a line of tight wire along the top of his fence. The wire has to be of very thin gauge so that the pigeons cannot get a grip on it to roost. It worked.
This system will work with possums too. Make certain that the wire you use is of very thin gauge on which the possums cannot get a grip on to walk along. They use telephone cables to walk along, and are consummate acrobats, so your wire MUST be very thin.
Climbing barriers
We were having very serious problems with possums in the City Botanic Gardens in Brisbane, where they were killing off some of our very old ‘heritage’ trees.
They had a fondness for these particular trees and kept nibbling on the new leaf shoots. As soon as new shoots were formed they would have a feast on them and, of course, if this goes on long enough the trees would be unable to replace their older foliage and would eventually die. Our trees WERE dying.
I copied an idea I had seen before. I wrapped the base of the tree around with a very wide sheet of thick plastic which prevented the possums from climbing up the tree. They could not get a grip on the plastic. They can certainly get down to the ground by jumping the last metre or so, but then they cannot climb back up again. You could use galvanised metal sheets, colourbond, perspex or any material which is hard and on which possums cannot get a grip for climbing.
Sprays
I have tried spraying with mixes made of chilli, garlic, neem oil, castor oil and a host of other products. I have tried spraying some of the commercial formulations sold as deterrents for possums. None of them have worked.
One product that DOES seem to have an effect is a fungicide called THIRAM. An interesting observation I came upon accidentally was that a particular section of roses, and a batch of potted annuals, which I sprayed with Thiram for fungal problems were not affected by possums. The night after the plants were sprayed possums had eaten the plants that had not been sprayed but left the sprayed plants alone. Maybe there is something in this?
I checked on the product and find that whilst Thiram is registered as a fungicide against various fungal problems, it is also registered to prevent damage from rabbits, rodents and deer in the USA. It is not registered as a measure against possum damage in Australia. Very interesting! I will follow this up in due course.
Can anyone tell me where in Brisbane I could buy THIRAM
Thanks