All about plant fertilization

Fertilizer for boxwood – [How and when to fertilize]


The boxwood shrub is native to Europe and is characterized by supporting various climates and soils, and is currently cultivated almost all over the world. In ideal conditions it can reach up to 10 m, and its bushy characteristics make it ideal for giving very decorative shapes with good pruning. But in this article we will not talk about pruning, but rather we will concentrate on explaining everything related to the use of fertilizer for boxwood. We will see how and when to fertilize, and what are the best fertilizers for these shrubs.


We will see all the general guidelines so that you can successfully fertilize a boxwood. But keep in mind that fertilization is not a strict law, many factors can cause it to change. Some of the factors are the specific variety of boxwood, climate, soil and age of the bush, etc. Therefore, once you have read this post, you will have to try a fertilization plan and modify it until you achieve the desired results in your bushes.

1. What do the NPK values mean in a fertilizer?


To begin the article, the first thing we will do is analyze a fairly important concept in fertilization. This concept is NPK values, which are three numbers separated by a hyphen that you have surely seen on fertilizer packages.

Each number within the NPK values represents the three essential nutrients which are as follows:

  • N: represents Nitrogen which is a very important nutrient for plant growth. It allows for exuberant development of both leaves and stems.
  • P: this letter represents phosphorus which is key for the development of roots and flowers. In floral plants it is very common to fertilize with phosphorus to improve flowering.
  • K: this last letter represents potassium, which helps strengthen the plant’s immune system. A plant with its strong defenses is able to better withstand attacks from pests, diseases or resist drought.

Therefore if you buy a fertilizer with NPK values 10-20-15 it means that; 10% of the total weight is nitrogen, 20% is phosphorus and 15% is potassium.

In summary, by understanding what NPK values are, you can quickly know the nutrient concentration of a fertilizer. This will make your task easier when buying fertilizers. 😉

2. What is the best fertilizer for boxwoods


Like almost any plant in our garden, you can fertilize it with both organic fertilizers and commercial fertilizers. Personally I like to fertilize my plants with mixed fertilization plans. That is, I try to make my plants benefit from the strengths of both types of fertilizers.

Below I will leave you a list of the best fertilizers for your boxwood. Obviously I will divide them between commercial fertilizers and homemade organic fertilizers.

If you are reading this post, you will probably be interested in learning about fertilizing these other plants.

2.1. Homemade Organic Fertilizers

With organic fertilizers you will generally see long-term results. If you want more immediate results you should use commercial fertilizers.

But by using organic you ensure that you do not add any chemicals to the soil, since they are 100% natural. In addition, many of them allow you to reuse the waste you generate at home, saving money.

  • Compost: without a doubt this is the organic fertilizer par excellence, and my favorite. Depending on the ingredients with which it has been made, it will have one or another nutrient composition. But it will always enrich the soil and improve its structure. It is best to do it with organic waste from your kitchen and garden.
  • Manure: Properly fermented manure from animals such as cows, horses or chickens is very good for plants such as boxwood. You just have to make sure that it is well fermented, otherwise it can burn the plants due to excess nutrients.
  • Fish emulsion: this fertilizer is a good source of nitrogen, phosphorus and potassium. It is a very common liquid fertilizer to obtain, and also quite easy to make at home.
  • Epsom salt: this fertilizer is characterized by being a very good source of magnesium. On certain occasions it is good to add magnesium to your boxwoods.
  • Ground coffee: this is undoubtedly one of the easiest homemade fertilizers to prepare. And if you like coffee, you undoubtedly produce a lot of it at home. In case you didn’t know, it is a good source of nitrogen, so you can use it on your boxwoods.

Let’s now look at some commercial fertilizers.

2.2. Commercial Fertilizers

Although commercial fertilizers will always cost us more money than any organic fertilizer, especially if it is homemade, applying it has its advantages.

In a compost we can never know the exact composition of nutrients. While with commercial fertilizers we know exactly what nutrients we apply and in what proportions. This allows us to regulate exactly the quantities that we must apply.

If applied correctly, commercial fertilizers will give your plants a boost that you won’t get with organic fertilizers. The problem is that if you apply it incorrectly or excessively, if you do so you will be contaminating the soil and you can even kill your plants.

Let’s see what type of commercial fertilizers you can use on boxwood bushes.

  • Granular fertilizers: it is very common to find fertilizers in granular format, if you are lucky you can even find them formulated specifically for these shrubs. If you can’t find it, I recommend looking for balanced granular fertilizers (e.g. 10-10-10).
  • Slow release fertilizers: they are characterized by releasing nutrients gradually. It can spend up to 6 months slowly releasing nutrients. This reduces the risk of overfertilization. They are good to apply to your boxwoods.
  • Liquid fertilizers: They are fast-acting fertilizers. That is, they are the opposition to slow release. In the case of boxwoods you must ensure that they are balanced.

Whatever fertilizer you apply, I recommend that you read the instructions for use. And it is always better to use a slightly lower concentration than recommended in its instructions. It is better to underdose than to overdo it.

3. How to fertilize boxwood


Fertilizing this shrub is not complicated at all. But you are reading an article about how to fertilize boxwood, so I am forced to detail how to do it step by step. 😉

  • Determine the right time: knowing when is the exact time to fertilize is very important. As important as applying the right fertilizer or doing it following the correct steps. In the next section we will see in detail when you should fertilize the boxwoods.
  • Choose the fertilizer: we already mentioned in the previous section which are the appropriate fertilizers for boxwoods. From them you can create an appropriate fertilization plan.
  • Calculate the amount: In the case of commercial fertilizers, you must read the fertilizer label to determine the dose. In organic fertilizers it is more difficult to exceed the dose, so do not be so afraid when applying it.
  • Fertilizer application: depending on the fertilizer, the application changes. For example, a liquid fertilizer must be dissolved in water and then applied as irrigation. While the compost should be applied to the base of the boxwood and mixed with the soil. In the case of granular fertilizer, these must be distributed evenly at the base of each boxwood. Always avoiding contact with the stem to avoid burning it.
  • Irrigation: it is always advisable to apply deep irrigation after fertilizing. No matter what type of fertilizer it is, this should always be done. It will help distribute the fertilizer better and dilute it. In this way it will reach the roots better.
  • Mulch: optionally you can apply a mulch of organic matter at the base of the boxwood after watering. This way moisture will be better retained and the soil temperature will be regulated. It will also help prevent the appearance of weeds.
  • Control and monitoring: it is important to always be attentive to your boxwood bushes. Observe them regularly, especially during the growing season. Look for any yellowing leaves, as this may be a sign of nutrient deficiency. Something that you can solve with an extra application of fertilizer.
  • Avoid excessive fertilization: as I already mentioned on several occasions, it is important to never overfertilize. This is because a deficiency of nutrients will always be easier to solve than an excess of them. Burns due to excess nutrients are something very difficult to reverse.

If you follow the previous steps you can keep your boxwoods healthy and strong. But to help you even more I will leave you the fertilization plan that I use with my bushes.

4.1 Fertilization plan for boxwoods

Below I leave you my fertilization plan for boxwoods. Keep in mind that you can vary this plan to your liking, if you see that you get the results you are looking for and your boxwoods grow healthy and strong, the plan is good. 😉

In early spring I like to apply 10-10-10 granular fertilizer. This is to give them a boost of energy before they start sprouting. Although this may vary with each fertilizer manufacturer, generally between 30-50g of fertilizer per m2 is applied around the bush.

When summer comes I usually apply a slow release fertilizer. In my case I buy spikes of balanced fertilizer so that it releases nutrients little by little over several months.

The last fertilization was carried out in the last days of summer. At that time I applied about 2-3 cm of fertilizer to each boxwood around its base. With this I seek to improve the structure of the soil and prepare it so that it is in good condition for next spring. During the fall and winter I choose not to apply any type of fertilizer. I let the bush rest completely in these months.

When I notice yellowish leaves between the veins I use Epsom salt. Obviously I first try to make sure it’s not a disease or pest. Then I dissolve about 15 g of Epsom salt in 4 liters of water and water each of my boxwoods with this mixture.

4. When to fertilize boxwood


To finish this post, let’s review when you should and when you should not fertilize your boxwoods. Although I already mentioned it indirectly in the previous section, it is good to make it clear again.

Fertilization season for these shrubs is during the growing season. That is, it begins in the first days of spring and ends in the last days of summer.

It is not recommended to fertilize boxwoods during the fall and winter. This is because the bush rests in those months. And fertilization could, for example, induce early budding, shoots that can freeze on cold winter days.

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