When to fertilize roses?

Fertilizing Roses

Roses are heavy feeders as they put lots of energy into flower production, making large demands on the soil. If one or more of the necessary elements is deficient in the soil, we begin to see the signs of hunger. If a rose does not have adequate nutrients, it will not have the ability to successfully fight off diseases and pests and will become susceptible to damage. Therefore it is very important that roses are fed regularly.
for signs and symptoms of hungry roses.

There are many forms of rose fertilizer:

Natural fertilizers:
A regular, generous application of well rotted animal manure or compost and blood and bone are perfect for roses. Avoid manure from animals that eat meat and use chicken manure sparingly – as these are too acidic for roses. Blood and bone gives an immediate burst of nutrients but should only be used once or twice a year in winter and the manure or compost provides a continuous release as it breaks down. A quick foliar feed every so often of Charlie Carp or Seasol is a good pick me up for the plant.
Pelletized fertilizer:
Pelletized fertilizers such as Sudden Impact are applied by sprinkling around the base of the plant. Use a reputable brand and follow the manufactures instructions on the packaging.
Liquid fertilizer:
Use a reputable brand and follow the manufactures instructions on the packaging. Never apply liquid fertilizer to dry soil as this will burn the roots – water the roses first.


Fertilizing should be done three times a year beginning with the first flush in spring, another at the start of summer, with the final application being at the start of Autumn. DO NOT feed after the autumn flush, as this encourages fresh growth at the wrong time. New growth leading into winter is not ideal as it may become damaged from the frost.

Foliar Feed:

This is type of fertilizer is applied by spraying the foliage of the plant. It has the unique advantage of reaching the sap flow in the stems only hours after being applied and will help give the rose lovely, glossy green leaves. This is to be used in conjunction with other fertilizers and is not to replace soil fertilization.
Application: weekly or fortnightly.
Charlie Carp is a great example of this, mix with water and spray the foliage once a week for the best results. This product can also be mixed with other eco friendly sprays such as Eco-Oil and Eco-Fungicide, providing protection against pests and diseases.

You CAN over feed your roses!

Do not over feed your roses. If roses are over fed, you will notice excessive growth, the plant growing larger than normal and with reduced flowers. Also note that some soils already contain sufficient nutrients for roses and may not need feeding a regularly as recommended, judge this on how the individual plant is growing.

Rose Care Calendar


Maintain moisture levels by a weekly deep soak.

The once flowering roses can be pruned back following their flowering display in late November / December.
Spider mite can be an issue in hot dry weather. Spraying with water underneath the foliage will discourage the spider mites. Two sprays with a miticide a fortnight apart should control severe outbreaks.

Fungal problems are usually not a problem during South Australia’s summer season unless on the rare occasions there is extended rainfall.

Now is the time to plan the rose bed. Select a site that receives six hours of sunlight each day. When replacing poor performing roses remove the old rose and as much of the roots as possible and incorporate organic material, Neutrog’s Seamungus and GoGo Juice into the area.

In late summer a full deadheading program will ensure plenty of blooms for the Autumn Rose Show. As a guide, trim your roses fifty days before the rose show or an autumn wedding for a magnificent display. Apply Sudden Impact for Roses around this time.


Keep your rose bushes in tip top condition with preventative sprays of Triforine, Mancozeb Plus, Pest Oil or eco oil. Fungal problems usually occur when there is moisture on the leaves for more than six hours.

Fertilize in early autumn with Sudden Impact for Roses if there was no application in February.

Autumn is the ideal time for roses and the production of quality blooms. Remember the fifty-day rule for rose trimming before an event where you need the rose garden to be at its best. Continual deadheading throughout autumn will ensure the display until cold winter weather sends the rose into dormancy.

Order your mail order roses and continue your soil preparation for the new roses.

Suppliers include:

Knight’s Roses, http://www.knightsroses.com.au/

Mistydowns Nursery, http://www.mistydowns.com.au/

Newmans Nursery http://www.newmansnursery.com.au/

Reliable Roses, http://www.reliableroses.com.au/

Ross Roses, http://www.rossroses.com.au/

Treloar Roses, http://www.treloarroses.com.au/

Thomas For Roses, Phone 08-83897795

Wagner’s Rose Nursery, http://www.wagnersrosenursery.com.au/


Winter is the best time to prune your roses. Remove dead, non-productive canes and spindly growth. Remove suckers, ensuring that water shoots are left. Cut back remaining canes by around a third, remembering that harder pruning produce fewer but better quality blooms while more blooms are the result of a light prune. Clean up around the base of the plant and spray with lime sulphur or an oil-based spray.

Bare rooted roses are planted out in late winter. Upon arrival place the bare roots in a bucket of water for one or up to twelve hours to allow hydration of the roses. Dig your hole and spread the roots over a slight mound at the bottom of the hole. Back fill and ensure the bud union is level or slightly above the surface of the rose bed. Water well and maintain soil moisture as the rose develops. No fertilizer is applied at this stage, but a soil conditioner such as Neutrog Seamungus is highly recommended and can be added to the base of the planting hole. Label your roses and make a planting plan.

Recommended plant spacing 1.3 to 1.5metres for hybrid tea and shrub roses, 1metre for floribundas, patio and ground covers. A half metre is usually sufficient for miniature roses.

Winter is the recommended time to shift roses when they are dormant. Prune the rose before transplanting. Apply Neutrog Seamungus for healthy plant development

Mulch around your roses in late winter to avoid damage to new growth if mulching is left until spring.


Fertilize with Sudden Impact for Roses when growth first appears.

Ensure you have mulched around your roses.

Stake new water shoots.

Keep black spot and mildew at bay by protective spraying with Triforine or Mancozeb Plus. Pest or eco oil will quickly control any scale problems.

Avoid spraying insecticides to eliminate aphids, as the beneficial insects will quickly control these pests. Squirting a jet of water will help keep them under control until the beneficials take over.

Enjoy the pleasure of roses in the home by cutting the blooms early morning or evening and placing in a bucket of water.

Looking After Roses

Sophie Thomson

SOPHIE THOMSON: Ok, Let’s set the record straight. Roses are not demanding plants as long as they’re grown in the right position and you feed them once a season in the warmer weather, all they need is a little bit of extra effort in winter – and that’s now.

So, get out your secateurs, loppers and pruning saw and make sure the blades are sharp. You’ll also need lime-sulphur, a sprayer, compost mulch and some liquid seaweed. And I also like to have a rag soaked in tea tree oil or diluted bleach to sterilise my tools between roses.

For roses that flower all through the year, winter is the best time for pruning. But roses that have only one flowering, in the spring, should be pruned straight after they’ve flowered.

I find the easiest way to prune bush or shrub roses is simply to follow the 50/50 rule. That means we cut off 50 percent of the height and we reduce 50 percent of the canes at the base.

When I reduce the height of the canes, I try to prune six millimetres past a bud at an angle so the water runs off. When I’m pruning at the bottom of the rose, the first thing I’m going to do is remove any dead wood and here we can see these old woody bits that have died so we need to get rid of those. You have to get right in there. The next thing I’m looking for is any wood that’s crossing and stopping a nice clean, open structure, so that branch needs to come out. A bit more dead wood in there. And now, the structure’s opened up a lot. But on the far side, it’s actually all in too close together, so I’m going to crawl in round the back and take this whole branch out.

There are a couple of variations on this. With hybrid Tea Roses that produce very large blooms and less of them, I cut slightly harder and this stimulates better quality bloom. But with floribunda roses, where there are lots of smaller blooms, I cut slightly softer.

With Miniature Roses, I still use a 50/50 method, but I can actually start with hedge trimmers, cutting off 50 percent of the height and then when I’ve finished that, I just simply finish it off with secateurs.

It’s also important to remove any dead wood in the centre of the plant and any old wood that really needs rejuvenating. This might look brutal, but come spring, it’s going to look fantastic.

Standard roses are simply bush roses grafted onto a tall stem. To prune them, you can either go for the 50/50 rule, or even prune a little less. So I’m going to start by taking out any old wood and any crossing wood and then just simply reduce the height.

Now is also a great time to check the stake. Make sure that it’s attached to the stake with a soft, flexible tie rather than anything with a wire in it.

When it comes to climbing roses or pillar roses, the mistake that most people make is to try and reduce the height of the rose every year. Now first off, you don’t do anything for the first four or five years. Maybe tidy them up a little bit, but you don’t start your major pruning till after that. And then, rather than reduce the height of the canes, what we want to do is actually cut out one third of the canes completely, right from the base.

So once you’ve got the framework right, then it’s simply a question of reducing the laterals to short spurs that will then flower beautifully next season.

If I were to train this rose, which is both a pillar and a climber, against a fence, what I would need to do is simply grab this branch and tie it down horizontally. The growth that comes from horizontal branches will flower prolifically. But in this case, I’m going to train it on this framework to make it into a pillar.

Winter is the best time to do battle with fungal pests and other diseases. First, collect and dispose of any leaves and pruned branches. Then, using an organic lime-sulphur mix, spray the plants and the ground around them. Although you won’t see much growth in winter, there’s a lot happening below the ground. This is a good time to feed the soil and all the critters living in it. I’m putting on a layer of compost and then an organic mulch. This will stop any fungal spores splashing back onto the plant. Then water with a seaweed solution to stimulate root development.

There you have it. It’s not rocket science is it? Your roses are cut back, re-shaped and treated for pests. And with healthy soil, you’re well on your way to having trouble free roses in spring.

STEPHEN RYAN: Our front gardens are the face that we show to the world, so we want them to look at their best. And in inner-city Melbourne, Jane’s found a garden that needs the horticultural equivalent of a facelift.

How to Fertilize Your Roses

By The National Gardening Association, Bob Beckstrom, Karan Davis Cutler, Kathleen Fisher, Phillip Giroux, Judy Glattstein, Michael MacCaskey, Bill Marken, Charlie Nardozzi, Sally Roth, Marcia Tatroe, Lance Walheim, Ann Whitman

To care for roses and keep roses blooming again and again, you should fertilize them about every four to six weeks, although the type of fertilizer you use may alter this rule a bit. Always follow label instructions when determining how much fertilizer to use. You don’t need to fertilize roses that bloom only once in spring as often as repeat bloomers. Fertilizing once in early spring may be enough, but increase the number of applications if your plants aren’t green and healthy-looking or aren’t blooming up to your expectations.

Here are some general fertilizing guidelines:

  • Water before and after fertilizing: A plant stressed from lack of water is more likely to be burned by nitrogen fertilizers, so make sure that the soil around the plant is wet before you add fertilizer. Watering after fertilizing helps to move nutrients into the root zone.

  • Start fertilizing in early spring and stop in late summer or fall: Make your first application about four to six weeks before growth begins in spring or, in areas where winters are cold, about the time you take off your winter protection. Continue through summer until about six weeks before the average date of your first frost. Employees at your nursery can tell you exactly when that date is, but for most cold-winter climates, it’s sometime in late August or September. Later fertilization may encourage growth that will be damaged by frosts and can result in roses that aren’t fully cold resistant.

No fertilizer on earth will help your roses if the pH of your soil is too high or too low. When the pH is off, important nutrients already in the soil are unavailable to plants.

As long as you apply it often enough, you can use any type of fertilizer. The granular form is easy to use and doesn’t need mixing. Water soluble fertilizers get to roots quickly and are easy to use on container plants, but you usually have to apply them more often. Timed-release fertilizers are convenient, but alone they often don’t supply enough nutrients to keep roses growing well over a long time; you usually have to supplement with granular fertilizers.

The following list explains the major and minor nutrients your rose plants may need:

  • Nitrogen: Nitrogen fuels a rosebush’s growth, and you must add it to the soil regularly. This element stimulates dark green, healthy foliage growth; because a plant’s energy to make flowers is manufactured in its leaves, healthy leaves mean more flowers. Most rose foods have several times more nitrogen than phosphorous and potassium. Don’t worry about the numbers too much. Just don’t buy one of those “bloom” foods that has no nitrogen at all.

  • Phosphorus and potassium: Phosphorus and potassium are called macronutrients because roses need them in larger supplies than other nutrients. Some soils already contain enough phosphorus and potassium for healthy rose growth; adding more to them does little good. If your soil is short on phosphorus, add some directly to the planting hole when you put in your roses, so that it gets where it needs to go.

    Only a soil test can tell you for sure whether your soil needs either of these nutrients. But if you use a complete fertilizer — one with a lot of nitrogen and a little phosphorous and potassium — on a regular basis, you should be okay.

  • Iron: In areas where the soil is on the alkaline side, a rose plant may need applications of fertilizers containing iron. You know your roses need iron when their leaves turn yellow with green veins.

  • Magnesium: Many rose growers swear by magnesium applications, but only when the soil is deficient in magnesium. Magnesium sulphate — called Epsom salts in drugstores — is the form that’s usually applied. This chemical helps intensify flower color and increases production of new flowering canes. Water in 1⁄4 to 1⁄2 cup per plant once or twice a year.

What you feed your roses, and howoften, will affect its growth.

Roses need three primary nutrients — nitrogen (the “N” on a fertilizer label), phosphorus (P) and potassium (K) — as well as a number of secondary and trace elements in order to thrive. Nitrogen promotes foliage growth; phosphorus encourages healthy root and flower development; and potassium maintains vigor. Calcium, magnesium, and sulphur (secondary elements) and trace elements (boron, chlorine, copper, and iron) also promote plant-cell and root growth.

Primary nutrients are available from both organic (derived from plant or animal life) and synthetic or inorganic materials. Synthetic fertilizers come in dry, liquid, or foliar liquid form. Work dry fertilizers into the soil (moisten the soil first) and water after application to carry the nutrients to the roots. Liquid fertilizers are added to water with an in-hose applicator, and foliar liquids are sprayed on and absorbed by the leaves. Whatever you use, be sure to follow the directions and dosages exactly. Excessive doses can damage plants.

Most roses need regular feeding — with fertilizers that are balanced for roses, your region, and your garden soil. Begin fertilizing newly planted roses once they are established — about three to four weeks after planting. Start feeding older plants in spring when new growth is about 6 inches long. At a minimum, species roses, old roses, and climbers need an application in the early spring as the buds prepare to open. Repeat-blooming roses, old roses, and climbers will benefit from a second feeding of liquid fertilizer after the first bloom, and modern roses need regular feeding.

Image zoom The Nitrogen Cycle is essential forstrong plants.

Alfalfa pellets worked into the soil are an organic source of nitrogen and can be used as a slow-release supplement in spring. Use pellets that are not feed-grade so your rose food doesn’t feed the rabbits. A time-release synthetic fertilizer applied in the spring and again in July will reduce the need for reapplications. In zone 6 and colder, stop fertilizer six weeks before the average date of the first frost and let plants harden off for their winter rest.

How to Read a Label

Image zoom Read labels to make sure you’re getting the proper nutrients.

A Guaranteed Analysis statement must appear on all mixed fertilizer labels. The label must indicate the proportion of each element present, as well as its sources (in this example, ammonium phosphate, potassium nitrate, etc.). The numbers 8-10-8 denote the percentages of nitrogen, phosphorus, and potassium present in this mix. This example contains 8 percent nitrogen, 10 percent phosphorus, and 8 percent potassium. Some fertilizers also contain secondary and micronutrients. Look for fertilizers with micronutrients derived from EDTA complexes as they are water soluble and hence immediately available to the root system. Rose foods containing all three levels of nutrients (primary, secondary, and micro-) are the best choice. In some cases, a soil penetrant will be added to the fertilizer to assist in delivery of the nutrients in clay soils.

Regular Feeding Schedule

Roses are heavy feeders. They require a constant supply of nutrients to sustain growth and bloom production. Here are two methods that will meet their demand for food:

1. The Organic Method: For a continuing cycle of decomposition, regularly space applications of fertilizers on the rose beds about every four weeks. It is best to work the fertilizer into the upper soil levels. This program can be supplemented with biweekly applications of fish emulsion.

2. The Chemical-Fertilizer Method: Start with a time-release synthetic in the spring and reapply midsummer, with monthly applications of a complete rose food (with all primary, secondary, and micro-nutrients) in between major feedings. Always follow label application and safety instructions when using a chemical rose food.

Get rose-pruning tips.

Seattle Rose Society

Fertilization is synonymous with production in roses. Plants must be fed if they are to remain healthy and produce good blooms. You replenish the nutrients consumed by the plant.

Strictly speaking, there is no such thing as an organic fertilizer. Organic materials feed the soil bacteria, which, in turn, break it down into inert mineral salts, the only form in which the plant is capable of absorbing them. Chemical fertilizers are generally faster acting than organic materials, since they require only dissolution in water to become available to the plant. However, organic materials are essential for a well-conditioned soil.

All products labeled as fertilizer must, by law, have the percentages of nitrogen, phosphorus and potassium listed in that order (N-P-K) on the container. Nitrogen produces vegetative growth; phosphorus promotes the root system and the bloom; potassium or potash stimulates the general health of the plant. If a granular commercial fertilizer is used, choose one with a general balance between the three main chemical ingredients and, if possible, one that also contains trace elements.

Soil bacteria are dormant until the soil warms up in the spring; therefore, too-early applications of fertilizer in the soil are wasted. However, some benefit can be obtained by foliar feeding plants with a water-soluble plant food during cool springs. 1-2 handfuls (use gloves, or a 1-cup measure) of granular fertilizer applied in April, June and August will suffice. Do not apply any fertilizer containing nitrogen after mid-September. Always water before and after applying granular fertilizer. If dry fertilizer gets on the leaves, rinse it off immediately.

Leave a Reply

Your email address will not be published. Required fields are marked *