Roses are one of the easiest plants to grow. Plant, water, feed occasionally and cut back when needed. Yet I hear so much ‘how to’ information it makes my head spin – ‘do this, don’t do that, add this product, don’t use this product, plant this way, avoid doing that’. For a new rose grower it is totally confusing and one reason I feel why many just don’t grow these wonderful plants.
So what is correct and be followed and what is really not that important?
As one who has been involved with growing roses for over 40 years with numerous tests and trials conducted I would like to dissect some of the common rose growing topics and provide my thoughts on the subject. I hope growers of roses may also start to look at some of the old information given which just gets recycled from publication to publication, rose expert to new rose grower and never ever questioned.
ROSE ARE GROSS FEEDERS
According to some in the media it has been said ‘Roses are Gross Feeders’ and regular heavy feeding is required.
But here are two questions.
- How much is considered gross?
- How much feed does a rose really need?
To keep a rose plant with sustained levels of required elements in the soil, we need to provide what has been removed from the plant throughout the year when cutting flowers, dead heading and winter pruning. Any more than this is really just wasted. My estimate is around ½ cup of feed per year is needed and can be added once or twice yearly or divided up and applied in small amounts throughout the year.
Another factor on feeding relates to plant size and expectations. A miniature rose will need less feed than a large climber and a once flowering shrub needs virtually nothing compared to a continual flowering long stem picking rose. By adding mulch will also reduce the amount of feed needed.
PLACING CARDBOARD BOX IN HOLE
When replanting in a rose garden where roses have been removed the soil is considered ‘rose sick soil’. I have heard it said ‘place a cardboard box in the hole where the old rose has been removed to create a barrier between the old soil and roots of the new plant.
I do like the idea as it teaches rose growers that a hole is needed to be dug and old soil removed however this is where it all ends. Unless the box is wax lined the box will collapse after the first watering and will have no barrier to stop the roots from growing through.
OPEN UP THE CENTRE OF THE BUSH
One of the most common pruning ‘rules’ say to ‘open up the centre of the bush and create a vase shaped bush’.
This ‘rule seems to have come from England where growers open up the centre to allow more sun to dry out the foliage. In Australia most areas have a different climate and this rule is really less important. In fact with plants growing larger here and the sun more intense I feel it is actually detrimental to the plant with the risk of sunburnt branches and not a rule that is necessary.
Growers should be aware of their climate and assess if this ‘rule’ applies to them or if a normal prune is easier and will create a better shaped bush.
What I say about this rule is ‘to prune to create a vase shape ultimately you create a plant that looks more like a donut’. All the growth around the outside and nothing in the middle. I feel pruning to create growth all over the plant really will create more open spaces for air flow than creating a ring of growth around the edge and nothing in the middle.
PRUNING TO OUTWARD FACING EYE
It is often said when pruning to ‘cut to an outward facing eye’.
This pruning ‘rule’ amuses me for anyone who has looked at their plant when it starts to grow after winter, will see that the top 3,4 or even 5 growing ‘eyes’ all sprout with 2/3 actually facing inwards. An ‘eye’ is in the axis of each leaf which spirals around the stems. I feel this ‘rule’ is similar to the previous one mentioned to try and force the plant to open up for better air flow.
CUT AT AN ANGLE
Another of the pruning ‘rules’ state to make all cuts when pruning at an angle to allow water to run off and avoid staying on the cut branch.
I can assume the theory here is if top of the cane is constantly wet ‘die back’ could enter the cane and this problem can develop. Not sure if anyone has looked at a freshly cut cane of a rose after it has rained but the cut, even if at quite an angle, is still wet. It has been proven in the UK that this ‘rule’ really is pointless and is irrelevant to pruning guides. My best advice is to not prune when raining or about to rain to allow the cut to naturally heel.
CUT BACK JUST ABOVE AN EYE
The last pruning ‘rule’ states ‘cut back a cane just above a good eye’.
I am sure somewhere in the world a rosarian noticed that when a cane is cut back too far above growing bud the wood above dies downward. There are some who will call this dieback but really it is just a natural process where the plant stops supplying sap to the unproductive branch it just dies back.
If you want a neat, clean plant by all means take the time to cut just above the bud but if like me and have a few thousand to prune I just cut back quickly knowing it will not be of any major concern.
DEAD HEAD TO FIRST 5 LEAF NODE
Although this sounds a simple way to identify how far down to cut finished flowers in real life it is too confusing for most novice gardeners. It is not wrong. But in some cases it is not right. It all depends on the variety for some roses have 7 leaves not 5.
The easiest way to dead head is just common sense. Cut back like picking a bunch of flowers is easy and no science behind it. It covers all types of roses and anyone can get it right. In most cases it is a fact but for me too complex for average or new gardeners.
SUCKERS HAVE SEVEN LEAVES
I have heard it said on many occasions that you can identify a sucker by counting the number of leaves.
This is a general statement for there are many varieties of rose that also have seven leaves. This statement is clearer when talking about modern bred roses which almost all do only have 5 leaves.
The easiest and most accurate way to tell if it is a sucker is to wait. Decide what to do when a flower forms. If it is different it is likely a sucker and if correct probably a water shoot.
30 LITES OF WATER WHEN 30 DEGRESS
Watering is one of the hardest topics to advise correctly. It is virtually impossible to advise a blanket number of litres per plant as soil types, weather, type of rose, how water is applied and type of mulch can all affect needs. I have heard it being said to water 30 litres when 30 degrees or 40 litres when 40 degrees. Sounds good in principle but lacks detail.
The best watering is done prior to any hot weather as it takes time for the plant to take up the water into its system. Drippers are the ideal way to water as they emit a set amount of water which as applied slowly so does move down through the soil better than a hose which is applied quickly. Water moves to path of least resistance which is mostly sideways across the surface.
If watering by a hose is the only option do consider ‘pulse’ watering. Here a watering is performed to pre-wet the soil. After a set time a second and even third watering can be done taking the water deeper into the soil profile.
I have found modern ‘in line’ drippers are a wonderful creation. Drippers are placed at regular intervals along a tube and the gardener can create a wet zone so it does not matter whether a miniature, bush or climber as enough water is provided in the zone for all to access.
CLEANING SECATEURS BETWEEN BUSHES
Most books and garden experts will state for the need to sterilise tools between bushes when pruning plants. It is stated that it is to stop the spread of diseases and virus’s between plants.
For me I am right on the fence on this subject. Each year I would help trim 30,000 rose bushes for sale and prune 5,000 established plants in the garden and have never cleaned tools between plants and never seen a spread of diseases. Am I lucky, or are the viruses and diseases on roses not transferred through secateurs?
The worst rose virus we know in Australia is Virus Mosaic and this virus is not transferred through sap but only though propagation material.
I would love to see a study conducted to see what, or if, any rose virus and disease is transferred by sap and whether this is a myth or fact. A secateurs blade is very thin at the end and the chances of diseases or virus being transferred to the blade must be very sight.
Note: It is amusing that I have heard of a gardener fastidious in their sterilising secateurs between plants when pruning yet see them cut from plant to plant when cutting flowers from different bushes. .
LARGE PLANTS ARE THE BEST PLANYS TO BUY
I have heard on many occasions that when selecting roses, or ordering, the best roses to select or get provided are the largest. Although having a nice strong plant seems ideal in reality this is not what makes the best plant to buy.
In the Horticultural world most of the best plants are younger. We are offered seedling in punnets, tube stock and yearlings with these identified as grown to the best size for transferring to the garden and survival. We also have the advantage of cost as plants can be in a smaller container or brought up to a size quickly saving cost.
In roses the best rose would be a well hardened yearling plant however the public demands on nurseries see 2 year olds recommended as the ideal plants to get. For my private garden I have always planted smaller yearling plants when I can as they establish quickly with no problems.
My concerns over large plants are 2 fold. Firstly it is the root system. When grown in the ground the roots can be over 1m long and when lifted from the ground these can be cut back to no more than 200mm long. If the tops are not cut back to balance the roots the plant will die back until equilibrium of roots and tops is created.
Secondly there are more chances of suckering occurring if a large plant has been severely cut back as the plant is under stress and this is when suckers can occur.
Another issue of concern, especially when buying roses in bags, is for growers to get the roots into a bag many do cut back the roots severely. This is the worst thing to happen as the roots are the driving force of the plant and needed to be strong for the plant to thrive.
VIRUS MOSAIC CAN SPREAD
On occasions a watermark look can appear on the leaves to be identified as Rose Mosaic. The Rose Mosaic is in the making of the plant and can only be transferred through cellular level. That is it can only be spread through propagation.
Several studies in the US have proven the rose virus Mosaic is either found in the rootstock or the scion material which infects each other as the plant is propagated.
There is no cure once a plant has the virus. Most nurseries do operate virus clean understock beds so new varieties are likely to be clean, however some old varieties of plants do have the virus already in them.
KEEP MULCH AWAY FROM THE ROSE BASE
It is regularly stated ‘keep mulch away from the base of the rose or it will cause collar-rot’.
This is another piece of cultural advice originating from overseas. In climates where constantly wet and when a particular understock is used there is a chance rot can occur however in Australia we use different understocks and our climate is mostly a lot drier.
To use mulch material such as Pea Straw, Lucerne, Sugar Cane, or bark are all fine. They are light materials allowing air flow drying them out and not allowing the constant moisture which may be a problem. I would be reluctant to use any small particle material close to the understock which will settle and not have good air flow. Lawn clippings, sawdust, old potting mix or the new ‘super mulches’ may be a problem if they hold too much moisture.
In Australia one of the main benefits of mulches is to protect the plant from the hot summer sun. I would have seen hundreds of plants severely burnt as they are not protected from the extreme heat of the sun and why my choice for mulching is material which can be covered over the entire base of the plant. Unless in extreme locations this is a myth in Australia.
PLANT WITH BUD UNION ABOVE SOIL
When new roses are being planted it is regularly stated to plant the rose with the bud union an inch (2cm) above the finished soil level. Videos showing using a stick or ruler above the hole to make sure 2cm are common and really make it too confusing. I really do not know why this is said. All I can think is the thought of rot can occur at the bud union so to have above soil level will reduce the chances of the bud union rotting.
Today we have a large number of varieties grown as own root plants. Where is the bud union for these plants? There is none and these plants grow successfully with no issues. I have also seen plants grow better when the bud union is covered as it does protect it from direct hot sun.
There are also times when roses are deliberately planted with the bud union under the soil to allow the rose to take off on its own roots. Again this is contrary to what this advice says.
PLANT ON A MOUND
I recently watched a ‘how to;’ video on how to plant a rose plant. It stated ‘place a mound of soil in the middle of the hole and spread the roots over all sides of the mound. ‘If you don’t the plant will sucker’. It is sad such wrong information exists and is promoted to others to follow.
I am sure the answer would be to make the plant send out roots in all directions evenly. But not all plants produce perfect root systems and on occasions the roots are going in one direction. When planting my new garden over 2,000 roses were planted and none had a mound in the bottom of the hole and none of the plants had an issue.
As humans are we just thinking too much that a basic plant life needs help when really it just needs to be placed under the soil to let grow. As gardening should be made easy I say this is a myth.
ROSES DO BEST WITH A CHANGE OF DIET
I have heard it be said that roses, like people, do best with a varied diet.
Although in some ways this is correct mostly it is nonsense. Roses require specific elements to grow well and if provided in the correct rates they will thrive. One aspect growers need to understand is plants are basic organisms and do not need a change of diet. There are some occasions however when the soil is lacking elements and a top up is needed but in most gardens this is not needed.
For most rose growers around the country I would say changing ‘diet’ of a rose is not needed so would classify this as a myth.
DR HUEY IS BAD AT SUCKERING
Almost all roses on the market are budding onto understocks. Whether it be R. Fortuniana, Indica Major, Dr Huey or R. Multiflora for nurseries to provide a plant for you they are budded.
When a rose is budded there will always be a chance that sometime a sucker may appear. Mostly suckers appear from dormant ‘eyes’ left on the understock when the plant is produced however other times they can appear for no reason and roses budded onto Dr Huey do seem to be more common for this to happen than other stocks.
From my observations these type of suckers seem to be created from roses which are growing under stress. A rose budded onto Multiflora is likely to die however on Dr Huey the rose will send up suckers to continue to try and survive. In my garden I would have over 3,000 plants on Dr Huey and NO suckers exist yet less than 1km away is a public garden with similar varieties and understock, poorly maintained, and hundreds of roses gone to understock.
In the future as more varieties are sold on own root the chance of suckers will be less however some will not grow as cutting while others are not suitable so a budded plant will always have the chance of suckering occurring.
PRUNE IN JUNE
So many experts and books state the rhyme ‘prune in June’. Today with much better flowering varieties and changes to the season’s roses can still flower well right into mid-winter.
I feel the rhyme should now be ‘Prune in June is much too soon, prune in July and watch them fly’.
It is known that for every week late a rose is pruned it will be one day later it flowers so 1 month late is only a few days later in flowering.
A ROSE CAN BE KEPT SMALLER THROUGH PRUNING
Many times we talk with customers who want a short rose but like the flower on one that grows tall. ‘Oh we can always prune hard and keep it shorter’ they say.
All new roses are bred and the breeders study them and advise the size they will grow. Yes they can be cut back smaller but the plant will keep growing back to its full size again. To keep cutting back will not reduce its size but will reduce its flowering as it keeps producing new growth and less flowers.
To reduce the size of a plant can be done slightly by less feed, less water and different pruning methods but not by a huge degree.
Covered in this article are the most common rose cultural information I have questions on but other subjects still exist and further investigation should be undertaken. Topics such as ‘Roses have lost their scent’, ‘Climbers must be trained horizontally’ and ‘Roses do better on an understock’ all have questionable answers and need further explanation or study.
With improvements in rose hybridising, nursery practises and worldwide research a lot of what we knew is out of date so must be challenged to help make gardening easier or risk the loss of potential rose growers. And the loss of rose growers is what we can least afford to let happen.
Created 9/12/2021