FREQUENTLY ASKED QUESTIONS
Being a rose retailer we are constantly being asked questions relating to growing roses and their problems. With over 60 years as one of Australia’s leading retailers there is not much we have not heard.
These are our most frequently asked questions.
My Climber Won’t Flower.
When newly planted, climbing roses either flower or send up large climbing canes. If your rose is not flowering but has lots of large climbing canes, you have to wait until next spring for a mass of flowers along these canes. Do not prune these canes as this is the main framework of the plant and where the majority of the flowers come from.
When do I cut back a rose to have it flower at a certain time?
It takes roughly 58 days from cut back to next flowering although this can vary with temperature and variety. Trim the rose in stages over the period of 55 days to 60 to virtually assure the rose will be in some flower when wanted.
I was told to remove some soil with a rose removed, is this correct?
Although it is not known why, a rose will struggle if planted back into the same soil as a rose just removed. Options are to wait 12 months before replanting in the same spot, fumigate the soil (very expensive) or change over the soil (easiest). Remove 2 buckets of soil (300mm cube) and replace with soil from elsewhere in the garden. Old soil is not bad only poor for new roses so can be used elsewhere in the garden.
I was told to plant a new rose in a cardboard box when an old rose was removed, is this correct?
Some in Rose Societies have recommended this but there is no evidence to suggest this will help in any way as the box will break down in a matter of days and allow root to enter surrounding soil without delay. My opinion is the box gives you a clue on how much soil must be removed and replaced. But how big the box needs to be explained.
What are the silver insects under the leaves?
Most probably any silver insects located under leaves (if they look like aphids) are the ‘mummy’ of the parasitic rose wasp, Rosea Aphidius, who lay their eggs inside aphids killing them. Do not spray with any insecticide as having a predatory wasp in the garden can eliminate the need to spray with chemicals.
Can I get rid of aphids without spraying?
You can certainly wait for natural predators to control aphids but as it takes time for natural predators to build up their numbers you can use several other short term options. Use pest oil, soapy water (velvet soap sloshed in a bucket of water) or ‘hose off’ small infestations.
Are roses developed in Australia?
Most roses in Australia would have been developed overseas. Large companies develop new varieties and send the best to Australia which are introduced. For new every rose sold a royalty is paid to the overseas company. Roses have been developed here for over 100 years yet it has only been the past 20 which has seen incredible reliable quality developed to compete with the imports. The future of Australian bred roses is looking good.
My David Austin roses grow very large and do not flower well.
This is the case for many newer Austin varieties which can grow excessive sizes and unless the correct conditions are found will not flower well over summer and into autumn. A lot of older Austin roses are more compact and do flower well throughout the year. Sophie’s Rose is one I have noticed to perform well in summer and autumn. Do not prune Austin rose too hard in winter as this will also help with flowering.
I have heard David Austin’s can be used as climbers.
The definition of a climber does not fit with most Austin roses even though some are developed from climbers. A climber should have a limited number of base canes which can be spread over a structure. Austin’s have many basal shoots and are more large shrubs than climbers. If you would like to use them as a climber be prepared for a multitude of shoots coming from the base.
I have heard you can prune roses with a chain saw.
Several years ago we conducted trials involving rough pruning roses with saws. In our trials we performed a rough prune on 1 row and a traditional prune on the other row. For 8 years this trial was conducted. Our conclusion is a rough prune can be made on many ‘landscape’ varieties with floribunda’s and shrubs also flowering well with rough treatment. However, Hybrid Teas did not like this treatment too much and although flowering was better there was too much dead growth and shorter stems to recommend this as a good practice. My recommendation would be to certainly rough prune for a number of years but perform a traditional prune between to clean out the bush and extend it productive life.
Can Milk get rid of Black Spot and other fungal problems?
Milk will kill fungal infections that are on the surface of the leaf such as Mildew and Rust, but as Black Spot is located inside the leaf it is not controlled with milk. It is possible to reduce the chance of Black Spot on roses with a preventative milk spray, but if rain falls more spray need to be applied.
Is there a ‘Blue Rose’?
No. Unless a major breakthrough occurs in genetic engineering we will not see a true blue rose. Suntory in Japan has produced a ‘Blue Rose’ though their work but it is still a Mauve colour and not what we call blue. No doubt it will come one day and probably in our lifetime. As a breeder of roses I am interested to see what new colours can be created using a true blue rose more than having a blue rose as such.
What is the most popular rose in Australia?
Very hard question to answer indeed. Each year new roses come and go and popularities change depending on garden designs and marketing. Also each nursery grows different varieties and promoted their own differently. In general we state any rose selling better than Iceberg is a good selling rose as Iceberg is such a constant seller. For Ross Roses our top 10 are fairly stable although the order does change each year. Most years there are our top sellers: Crown Princess Mary, Just Brilliant, Mawson, Deane Ross, Red Cross, Double Delight, Pierre de Ronsard, Just Joey, Hans Heysen and Amazing Grace.
How can I stop dieback on my newly planted roses?
Most dying back of rose canes when first planted are due to them not being ‘hardened off’. A rose in full growth has sugars while when dormant these are changed into a stored starch. A rose with canes still in soft growth will die back naturally as an immature cane. A simple test to see if the cane is mature is the thorn test. Remove a thorn and it should appear brown on the stem under it. If watery or green it is not mature. Purchase roses from nurseries who use this test or if plants to be purchased in stores check the thorns on new green canes to see if ‘hardened’. If a plant has been bought and is dying back it may be best to remove the soft cane at the base.