As a professional rose grower for over 40 years I hear a lot about the subject of feeding roses with many different points of view. I hear everything from never need any feed through to those who feed for breakfast, lunch and dinner. So how much feed does a rose need and what is the best to feed them with?
In this article I would like to provide information based on my knowledge of a number of well-known products and offer some findings from tests we have conducted. This information is only a guide as individual gardeners may be better suited to different products due to their soil, availability, budget and climatic conditions.
To start I must state I have no commercial agreement with any fertiliser company. I do not receive any ‘kickback’ for promoting a product and do so only as I believe in the product totally based from using and gauging results.
Why do we feed?
Roses can go forever with NO feed added. A bold statement yet true. In the wild roses can grow for decades if not centuries with never any rose food added. How? Wild roses get most of their nutrient from their own plant material which falls to the ground, breaks down and is reabsorbed by the plant.
On occasions the plant may be lucky enough to catch other plant material blowing into its foliage or catch an animal which can’t escape its fierce thorns. All the nutrients a plant needs are in the soil where it is growing.
In modern gardens we do require more from our plants and do conduct activities which remove material which would naturally drop and be reabsorbed. The cutting of flowers removes growth and pruning old wood and taking away also reduces available nutrients in the soil.
We feed to replace what has been taken from the location through our human intervention.
How much to feed?
Based on my above observation the amount of food needed by any rose plant should equal the amount of nutrients taken from the plant. As most of the mass in removed flowers, stems and old pruning’s are mainly water very little material remains when all the water is removed and the remaining material condensed.
All we need to do is feed our plants to replace what has been lost which would estimate at around 1/2 cup of concentrated food. On top of this most gardens do apply mulch and this also must be added into the equation. Depending on the mulch we may see half of the needed nutrients added in this form. To also make this more complex miniatures need less feed and large climbers likely more.
In pots the amount of feed must be provided regularly and as much of the food leaches away with the watering a smaller amount than in ground plants is needed more regularly.
However all this information must be carefully thought through. For a rose to product flowers throughout the year would require more food and especially water than a plant which producer’s flowers more spasmodically or in cycles.
When to feed?
Most exerts do agree the best time (depending on what sort of fertiliser) should be applied after winter when the new rose growth is appearing. Organic fertilisers do take more time to break down and need to be applied earlier than manufactured chemical fertilisers which dissolve quickly and need to be applied only when plants have broken their dormancy.
More of the contentious question is how often? For many years we have conducted a feed after winter and another after summer. With changes to the garden we withdrew our summer feed with no significant changes to plant size, flowering or new growth. Water was the key and the soil had the available material to help make the new growth.
For roses in pots this is different for potting mixes are only just growing medium and do need more regular feed. Most state monthly which I cannot disagree however at worse bi monthly can be successful.
What types of fertilisers?
To feed plants consumers are faced with a multitude of choices and without help it can be confusing. We see advertised Organic, Chemical, Slow Release, Liquid or Animal manure.
Organic Fertiliser – I feel the best type of fertiliser is one that not only feeds the plants but helps improve the soil. Organic has this reputation yet today there are many variations from pure organic fertiliser through to those with some adding trace elements.
Depending on what is added we can experience problems in the garden if some added ingredients are at too higher levels than needed. Copper is one element which needs to be in control as it can affect worm levels in the soil. Too much Sulphur is fine for alkaline soil but a real problem in Acidic soils.
I recommend Dynamic Lifter, Katek and Rapid Raiser as three excellent products which are basic poultry mature and give high levels of nitrogen in the form or an organic material.
For plants to adsorb the needed elements a soil rich in bacteria is needed for it is the bacteria which break down the material into a form the plants can take up. In most soils the numbers of bacteria is sufficient however soil recently under plastic or concrete can benefit from the addition of more bacteria. Go Go Juice is an excellent product to add the needed bacteria if the soil is lacking. There is no harmful effect from using too much as the soil will regulate how much it can support so it really is just throwing money away if using too much.
Tests show soil bacteria convert both organic and chemical fertiliser at equal rates so any extra added will help no matter what types of fertiliser used.
Chemical Fertiliser – Fertiliser seen in many garden centres labelled as ‘rose food’ is probably chemical fertilisers. These are manufactured with elements in the correct proportions to give the plant what is needed for optimum growth.
Chemical fertilisers are purely feed and do little to improve the structure of the soil or add the organic material vital to create a healthy soil environment.
These products do however have a use in rose growing. As the product dissolves quite quickly it is ideal to get a quick ‘hit’ to a plant for instant growth. This is ideal for potted plants.
Slow Release – As the name suggests slow release fertilisers are plant food encased in a membrane which slowly dissolves providing the food to the plant in a controlled manner. Another name for these types of fertilisers is Controlled Release Fertilisers.
The main uses for these types of fertilisers are when planting new plants in the ground or providing feed for roses in pots.
Liquid – There are only a few liquid fertilisers on the market plus some other liquid products some feel, and use, as fertilisers which are not.
Liquid fertilisers are a watery based bottle of concentrated feed ready to be taken up by the plant giving an instant hit to any plant fed with it. Products such as Sudden Impact for Roses and Power Feed are two of the more popular products and both are excellent to use for that quick hit of food.
In this section I would like to mention another popular product.
Seasol has been around for quite a while and many ‘feed’ their plants with it. This product is not a plant food but more of a soil tonic proven to help new plants form roots. Any struggling plant can see vast improvement with a regular using of the product. It is one product I highly recommend to have in the shed in case of need.
Animal Manure – Times have moved along since the picking up of horse manure or cow manure from a field.
Most animal fertilisers are pre-packaged and well rotten avoiding the heat a fresh material can have if added to the garden. In the bags the products are refined, do not have the weed or oat seeds and can provide a garden with a rich organic material ideal for plant growth.
Mulch – Although not a fertiliser the addition of many types of mulch can feed the plants with as much ‘food’ as they require. High nitrogen mulches such as Lucerne, Pea and Bean straw are known to possess all a plant needs to thrive. Consider what is found locally with rice husks, grape mark and sugar cane all possible and found in different regions. The newly created Who Flung Dung helps keep moisture in the soil with the bonus of added ‘food’. This product may eliminate the need to both mulch and feed as it is all in one.
The most important fact any gardener must remember is with any food there needs to be water. Fertiliser no matter what type needs to be dissolved to get into the soil or taken by worms deeper in the soil profile. For a healthy worm population there needs to be feed, water and low levels of harmful elements. Get this balance right an your roses should thrive.
Created 20/8/2019