Feeding Roses After Planting
Roses grow best if they have good amounts of water and nutrients. They make stronger, healthier plants which are more resistant to disease and produce more flowers.
There are a number of rose fertilisers available, these are made with the correct ratio of essential elements (Ammonium and Nitrates: N, Phosphorus: P, Potassium: K, abbreviated: N:P:K) together with other trace elements, and are available in both dry and liquid forms. It is best to use these fertilisers, following the instructions for dilution (liquid) or rate (dry) on their labels.
Roses do not need fertiliser when they are not growing, doing so is wasteful in both terms of cost and leaching (when the fertiliser is washed through the soil without being used by the plant).
We do have calls from customers who ask about using the very old, organic fertilisers such as hoof and horn, bonemeal and blood; we are not saying that they don't work, but they are pretty unpleasant to use and store, are slow to work, and are loved by foxes who will dig up all around the plant looking for food. We would strongly advise not using these products.
Organic manures are available such as chicken pellets, these are sterilized (so are safe to use), but it's important to look at the ratio of the elements that are in the product, often they are high in ammonium and nitrates (N) which can make the plants grow too lush. As a rule, for roses the ratios should be three times potassium to nitrogen and phosphorus so: 1:1:3 (N:P:K) or 10:10:30. The ratios are the same, but the amount of product in the second example is ten times higher by weight compared to the first example, so the application rates for each product will vary.
Slow-release fertilisers are worth a consideration as they are made to release nutrients gradually through the growing season triggered by moisture and temperature. They are available with different lengths of activity, we use a nine-month slow-release fertiliser in our compost, but six- and three-month versions are available, again check the composition of the fertiliser. Rose fertilisers are readily available online and at garden centres.
Feeding Roses in Containers
- With a good compost there is usually sufficient fertiliser to maintain the plant for a few months after planting
- After the first flowering when the plant has been dead headed consider feeding
- Use a liquid feed for plants in containers*
- Repeat after a month or so
- Do not feed after the end of August as there will be sufficient food to take the plant into autumn (dormancy)
*Liquid feeds are good for container grown plants where the root system is restricted to the size of the container, they are formulated in a way that makes the nutrient readily available to the plant and because they are mixed with water are pushed into the root zone. It also saves a job as watering and feeding can be done at the same time.
Alternately use a three-month, slow-release fertiliser stick pushed into the compost in June this will carry the plant into the autumn.
Feeding Roses in the Open Ground
- During the first year after planting (and for climbers growing against walls where the soil can be dry) consider using a liquid fertiliser. This can be done at monthly intervals after the first flowering until the end of August. This does two operations at the same time giving the plants water and nutrient together.
- Continue with the above regime if it is convenient and getting good results in following years and in prolonged periods of dry weather.
- As the plants get older consider using a dry rose fertiliser.
- We would recommend an annual application of dry fertiliser on established plants.
- For best results with dry fertiliser fork the product well into the top 10 or 15cm of the soil around the base of the plant (in a circle away from the stem to a diameter of about 25cm). Do this early in the year, perhaps as early as mid-February, this enables rain to start to wash the product into the root zone so nutrients are available as the plant needs it and starts to grow.
For gardeners with access to good quality manure, annual mulching early in the spring around the base of the plant may provide sufficient nutrients without additional fertiliser.