Known for their beautiful flower heads and lush foliage, hydrangea or hortensia is a popular garden staple with a long bloom period. With more than 70 species of flowering plants, hydrangeas are certainly diverse.
While hydrangeas are easy to cultivate and tolerate almost any type of soil, to maintain these gorgeous flowers and get the biggest blooms, it’s important to feed them regularly and with the right nutrient balance.
In this article, we will reveal the best hydrangea fertilizers, as well as some useful tips on how and when to feed these shrub-like super bloomers.
Jump straight to Best Hydrangea Fertilizer Product Review
What is the Best Fertilizer for Hydrangeas?
Feeding hydrangeas is fairly simple once you learn the basic rules. Almost all the varieties of hydrangea benefit from light, well-drained soil. If you are growing your hydrangeas in heavy clay soil, you may want to add some compost or leaf mulch to your soil to improve its texture and add air. This applies to pretty much all plants, right. Then there the soil pH, which we will cover shortly, and of course the actual nutrient ratio within the fertilizer you use.
To avoid damaging your hydrangeas, I would suggest you try to avoid using quick-release fertilizers containing high amounts of nitrogen, as this produces excessive foliage growth at the expense of flowers. Pay attention to the first of the three numbers on the fertilizer ratio on the packaging, the letter N of (N-P-K) which is the nitrogen content.
Ideally, you want a balanced fertilizer where all three numbers are the same for example 10-10-10 or a high Phosphorus fertilizer such as 5-10-5. Just avoid a high nitrogen product where the first number is significantly higher then the others.
Fertilizers come in different forms and require different application methods. Here are the most common types of fertilizers and how to use them:
Organic fertilizer can consist of manure, bone meal, guano, or any other combination of organic products to produce an excellent food source for your hydrangea. Of course, there is a trade-off in using organic fertilizers, in that you may need to blend them to get the perfect mix, and of course, we need to touch on the delicate topic of the smell.
If organic fertilizer is made of manure then it may smell or the local wildlife may take an interest in it.
Synthetic man-made fertilizers are produced with very specific nutrients and control. Meaning they can be fast-release or slow-release and contain the exact nutrient ratio (N-P-K) the manufacturer wants to include. This has fantastic upsides, but of course, they are not organic.
When choosing a chemical fertilizer, opt for a slow-release, balanced granular product that’s formulated for shrubs. This type of fertilizer works well on hydrangeas, but it must be covered with enough soil in order to release it properly.
If I had the option, I would use organic every time, but life is just not that simple. No doubt you will have your own views on this, so fortunately there are a number of excellent organic and synthetic products available for all purposes.
How to Fertilize Hydrangeas?
Knowing how to fertilize hydrangeas is just as important as the product you use to feed them with. The amount of fertilizer used depends on the size of the plant as well as its root system. Applying too much fertilizer is much more harmful than under-fertilization. You’ll risk burning the plant, diminish bloom, or even worse, kill the hydrangea.
The application of fertilizer will depend on the form you purchase, spikes, powder or liquid concentrates, so be sure to follow the manufacturer’s guidance. We will cover each area in detail throughout this article but in summary, you can take this guidance:
- Check your soil pH with a soil pH meter
- Amend your soil to achieve the coloration you require for your hydrangea. 5.5 or less for blue flowers, 6.5 or above for pink flowers
- Apply fertilizer in early spring and late fall or autumn
- Use a half-pound of fertilizer around the base of the shrub and rake into the ground
- Water in if no rain is forecast
I’m a huge fan of fertilizer spikes and they can be used on hydrangea. They provide a slow-release fertilizer that will last most of the growing season once they are inserted into the ground. However, to my knowledge, there are not any spikes on the market that are suited to the nutrient requirement of hydrangea so I would steer clear of them.
Powder and Granular fertilizers
Powders and granules are the most popular form of fertilizer for use on hydrangea and shrubs in general. They provide a middle-of-the-road option, slow-release fertilizer.
Generally they need sprinkling around the base of the plant and raking in for maximum effect. Then when the shrubs are watered or when it rains the solids dissolve and release their nutrients into the soil for the plant to absorb.
Liquid concentrates will need to be dissolved in water prior to applications. The main benefit of a liquid formula over other option is the rate of nutrient absorbtion. Once you water your hydrangea with the dulited fertilizer, it is readily available to be absorbed through the plants root system and therefore is fast activing.
The downside of such products being they tend to wash away quicker with rain or overwatering, so use them to provide a kick-start to get your plants fixed if they look like they are in poor condition.
Changing Hydrangea Color
We will all be familiar with the brilliant range of colors we see in hydrangeas and I guess that’s one of the main attributes that attract us to them in the first instance. So how can we make the best of this shrubs greatest assets, it glorious blue or pink blooms. The answer is in the soil…well at least the soil pH.
Hydrangea Color pH
White hydrangea cannot somehow magically be turned blue or pink by the grower, but you can significantly influence the richness of color for pink and blue hydrangea types by adjusting soil pH. This is what we call soil amendment, whereby we add either lime or sulfur to the soil to move it up or down the pH scale until we reach the perfect growing condition for whatever plants we are growing.
Before you can make any amendment to the soil you will need to know the existing soil pH level, and you can do this by using a soil pH tester. You can read more about testing soil for pH levels and nutrients here in my article on Soil PH Tester Kits.
how to make hydrangeas pink
For rich colorful pink hydrangea flowers, you will need to test your soil pH and amend the soil to a pH level of 6.5 or higher with the use of Lime or another alkaline product such as Jobe’s Organics Garden Lime.
how to turn hydrangeas blue
For vivid blue hydrangea blooms, you will need to amend your soil to be on the acid spectrum of the pH range, ideally between 4.5-5.5pH. Once you know your soil pH you can amend the soil using an acidifier such as Jobe’s Organics Soil Acidifier. This type of product’s main active ingredient is sulfur which amends the soil acidity levels.
It’s is important to closely follow the manufacturer’s instruction to make sure any quantity of soil amendment you add is controlled to achieve the desired outcome.
Best Hydrangea Fertilizers Reviewed
We delved deep into the market to find the best hydrangea fertilizers available. Our main considerations are the quality of the fertilizer nutrient balance, color performance, and ease of use. As well as our own tests and experts’ opinions, we also take into account customer reviews across many major online platforms and growers forums to demonstrate the overall customer satisfaction with the products we have reviewed.
This water-soluble plant food fertilizer from Miracle-Gro is a fast-acting granular feed that will work instantly on all acid-loving plants including hydrangeas. So when I’m looking for bright blue hydrangea blooms I know Miracle-Gro will get me results. With the help of this fertilizer, you can enjoy bigger blooms and luxuriant foliage for longer. It works by feeding, adding iron, and acidify instantly as a fast-release fertilizer.
How to use: For best results, use the hydrangea fertilizer once a week or every two weeks. You can either use a watering can or a sprayer. For outdoor hydrangeas: mix 1 tablespoon of the fertilizer with one gallon of water. For indoor plants: mix half a teaspoon (yes teaspoon!) per one gallon of water.
Since this product is fast working and yields great results, I would consider it as the best fertilizer for hydrangeas that need a kick-start to show color. It has the capability to transform pale washed-out hydrangeas into a strong natural blue after just one application.
I was pleased that this Miracle-Gro fertilizer for hydrangeas is in a granular form and not liquid. It’s easier to control and a little less messy to handle. Miracle-Gro can also be put to great use as a rhododendron fertilizer or when fertilizing azaleas.
Customer Reviews: The performance of this product is second to none with over 25,000 5/5 reviews. Miracle-Gro is a global brand that has gained a lot of trust through its consistently deliver customer satisfaction. A lot of customers were impressed at just how fast this product kickstarts a sad-looking plant and the consensus agrees with our view that it’s the best fertilizer for hydrangeas.
- Brings lackluster flowers back to life after application
- Fast-acting and highly effective hydrangea fertilizer
- A proven track record of delivering results
- Small packet for a premium price, but super-effective
Espoma Organic Bone Meal is a great addition to any flower garden when growing shrubs or bulbs. The 4-12-0 fertilizer ration provides a light dose of nitrogen and a high ratio of phosphorus to support excellent root growth, allowing your shrubs to suck up all available nutrients for outstanding blooms. It’s best to apply Bone Meal May and August, but the earlier the better for good strong blooms.
Anyone who reads my work will know I’m a big fan of Espoma organic range, you’re sure to be getting the highest quality products at sensible prices, you can check the latest price here. It’s available in 4lb, 10lb, and 24lb bags.
How to use: Use in spring and fall by applying 1 or 2 pounds depending upon size of shrub. Rake well into soil and water in.
Customer Reviews: Customers rate Espoma Bone Meal 4.5/5 for hydrangeas and love the results. Not surprisingly their dogs also loved the crushed bones! If you’re looking for a blooming fertilizer I recommend you give Espoma Bone Meal a try, I use it regularly and have nothing but positive things to say about it, hence it’s on my list of recommendations for you.
- Excellent organic product to be used for strong root development and outstanding blooms
- A lower nitrogen ratio prevents too much foliage development
- Organic products like this can tend to attract interest from wildlife
Our next pick of the best fertilizer for hydrangeas is an organic product from the brand, Espoma. The Holly Tone fertilizer comes in a generously-sized 18-pound bag and is specially formulated to work for many different types of plants, not just hydrangeas.
Those who have an organic flowerbed or garden will find this product especially useful for healthier plant growth. With its special Bio-tone microbes that no other brand offers, we are quite certain that your hydrangeas will love this all-natural fertilizer just as much as our plants did.
Just like Miracle-Gro, the Holly Tone fertilizer is also fast-acting and can be applied once per month prior to rainfall. What makes this product stand out, however, is that you can use it sparingly since it is purely of organic matter. You can buy it online here.
How to use: for young hydrangeas, prepare the soil and mix 2 cups of Holly Tone with one cubic foot of soil. For established hydrangeas, sprinkle 1 teaspoon of the fertilizer into 3 inches of soil along the outer edge of the pot.
Customer Reviews: Espoma is not as well known as some of the other brands in our trials, but the many experienced gardeners including myself have used it with great success. Consumers who use Holly Tone fertilizer feedback on how they notice healthier plant growth within a short period of time. So based on our experience and other users’ online reviews, we can safely say this is well-deserving of a place on our best hydrangea fertilizer list.
- Won’t burn the plant unlike some other fertilizers
- Fast-acting results
- Organic ingredients
- Can be premium priced in some regions
Another top-rated organic hydrangea fertilizer is the Jobe’s Garden Lime available from Amazon. An ideal granular fertilizer for increasing the pH levels in soil in order to promote plant growth. This organic granular maximizes the soil’s alkalinity since low pH can cause poor soil structure. Hydrangeas, just like most other flowering plants, grow best in a soil pH of between 6.5 and 6.8. Anything below the minimum 6.0 means the nutrients can’t be absorbed.
By adding the Organics Garden Lime fertilizer to your soil, the pH level will increase and the nutrients can be better absorbed. Note: Before applying this product, be sure to test your soil’s pH first.
If your soil is lacking pH, it may be the reason why your hydrangeas aren’t thriving. If you’re wondering how to make hydrangeas pink, this organic product will do just that, and help them remain healthy and vibrant throughout the season.
How to use: apply the granules at planting and again 2-3 times per year to maintain the right soil pH levels. Since this product is an organic fertilizer, it is safe for use around pets and children.
Customer Reviews: From over 2,000 users who tried this fertilizer for hydrangeas, a staggering 75% of them gave this product 5/5. They were especially impressed with how quickly their plants started flowering thanks to the bone meal and the other nutrients present in this product.
- Easy to pour bag
- Increases soil pH – turns hydrangeas pink
- Instant results (flowering occurs within 3 days)
- Doesn’t go far if you have lots of hydrangeas to grow
- So popular it is sometimes sold out
Jobe’s has come up with another brilliant product that promises to improve plant hardiness and its resistance to disease. Improve the color and appearance of your hydrangeas with this organic soil acidifier. It will effectively turn pink hydrangeas blue. The all-natural fertilizer can also be used for turf, blueberries, and azaleas.
The organic fertilizer works by decreasing the soil’s alkalinity using all-natural ingredients. The granular formula promotes darker green growth without harmful chemicals that can burn plants.
To balance the alkaline soils, this is the ideal fertilizer to use. However, be sure to test your soil’s pH before applying the product. Check prices here.
How to use: pour the granules at planting time and reapply 2-3 times per year to maintain the correct pH level in soil.
What we love about this organic fertilizer is its all-natural ingredients including sulfur, which is used to correct alkaline soils. Sulfur also helps produce the much-needed proteins that plants need, while gypsum helps develop vitamins and enzymes.
Customer Reviews: Users were just as pleased with the performance of this fertilizer as they were with the Garden Lime product from the same manufacturer, making this natural fertilizer from Jobe, another top quality product that must be on our list.
- Highly effective and fast results
- Won’t burn plants
- Easy to pour bag
- Small packet for premium price
Vitax Fertilizer for Hydrangeas has been developed to improve flower yield and provide a boost throughout the flowering season. With a nutrient composition (N-P-K) of 8-4-12 with added magnesium and iron, so it delivers high-quality foliage and large flower heads. Its primary purpose is a fertilizer and not a soil amendment, so you will not see any specific changes to flower color as you will with some of the other products we have reviewed.
I would rate this product in my top 2 selections if it wasn’t for its limited availability for gardeners in North America, although you can get it sent to the US via Amazon.
How to use: Apply one handful (35g) of Vitax Hydrangea Food around the base of the plant whilst planting. Through spring apply as a top dressing and lightly dig in or rake over the soil. In dry weather, make sure you water the ground beforehand for the best results.
Customer Reviews: A really simple top dressing to use, one handful per plant or 70g (two handfuls) per square meter. Customers report an average score across all retail platforms and forums of 4.5/5. However, this is a potent hydrangea fertilizer and you do need to follow the dosage instructions, customers who have been carefree have suffered from damaged plants. Buy from Amazon.
- A really good hydrangea food to support large blooming flowers
- Supports a full season-long flower display
- Powerful feed and manufacturer dosages must be followed
- Only available in UK
When to Fertilize Hydrangeas?
Young hydrangeas require light fertilization with a quick-release fertilizer in the months of March, May, and July. Once they start forming their buds, feed them with around 4 ounces of balanced fertilizer in early spring and again once they bloom.
Never fertilize hydrangeas after August as fall is the time for these shrubs to prepare for dormancy. Fertilizing around this time will weaken them pre-winter.
In warmer climates, late May and July applications will suffice. In cooler regions, it may be best to fertilize hydrangeas only once in June or July.
Whether you live in a warm or cold area, always stop feeding around two months before the first frost appears. While late fertilization produces plenty of lush growth, it can weaken the hydrangeas’ ability to withstand harsh winter weather during its dormancy period. Additionally, tender new leaves allow the cold to absorb into the foliage which can lead to the plant being damaged.
Expert tip: when to fertilize hydrangeas
To ensure the best growth, apply a low-phosphorus 10-10-10 fertilizer per 100 sq feet in March, May, and July. Make sure you don’t remove the mulch from the soil while fertilizing. The climbing varieties of hydrangeas can benefit from April and June fertilizing with a general-purpose organic or chemical fertilizer.
How Often to Fertilize Hydrangeas?
The rule of thumb is to fertilize hydrangeas once every month starting in March. This, of course, depends on when your region has spring and summer. If you live in a warmer climate, for example, your spring may only be a short season. Similarly, if you live in a cooler climate, you won’t have much of a summer so it’s best to consider feeding your hydrangeas once a month from March until July. Stop fertilization from August.
Some fertilizers have specific instructions on how often they can be used. In general, you may need to feed your hydrangeas every two weeks for a month and then once a month thereafter. However, this depends on whether you use fast-release or slow-release formula as you usually have to wait longer between feeding sessions if using the latter. So just be sure to read the manufacturer’s instruction to get the best out of the product you purchase.
Conclusion Best Hydrangea Fertilizer
Choosing the best fertilizer for hydrangeas is easy when you know what you’re looking for. For those who want a no-fuss, no mess organic fertilization method, the fertilizers from Jobe’s comes highly recommended by our team.
There is also the highly effective chemical fertilizer from Miracle-Gro that’s designed to thoroughly feed hydrangeas all the way to the leaves and roots and help them thrive. With all the above information we have put at your disposal, you should now be able to make the right choice and select the best hydrangea fertilizer for your garden!