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Best Fertilizers for Hydrangeas

Osmocote Outdoor Smart Release
This fertilizer get’s Greenpinky’s top pick because of its quality ingredients, price, and proper N-P-K ratio Check Price

Fertilizers make all the difference when you are trying to grow healthy hydrangeas. It can be challenging to select the right fertilizer because there are so many choices out there and it’s hard to see the effects of the fertilizer that you use until many weeks later. I’ve done the testing and compiled a list of the best fertilizers for hydrangeas for you. Keep reading to see our top recommendations.

Fertilizer Comparison Table: Top 6 Fertilizers for Hydrangeas

Here’s my easy-to-browse comparison table featuring the best hydrangea fertilizers that I will discuss further below. They are in price ascending order (based on time of review) and you can find some more details in regards to the N-P-K ratios of each fertilizer. Click on the green symbol to view more information if you are on a mobile device.

Best fertilizers for Hydrangeas

I have a variety of different fertilizers in my list. You’ll find all different types of fertilizers including spray fertilizers and dry granular fertilizers. The fertilizers are listed in price ascending order. Also remember to look at the N-P-K ratios to see how they fit your needs, I like 1-1-1 for hydrangeas.

  • N-P-K Ratio: 30-10-10

  • Fertilizer type: Water mix

  • Amount: 1 lb

Specially formulated for acid-loving plants, like hydrangeas, simply mix the appropriate amount in a gallon of water. This product begins working immediately, with double action feeding. It can be used as a spray while also feeding through to the roots. Be sure to water before feeding or apply following rain. Feeding dry ground can cause fertilizer burn. Seal the product well before storing it. Apply twice yearly, when foliage sprouts and when blooming ceases.

  • N-P-K Ratio: 4-3-6

  • Fertilizer type: Granules

  • Amount: 5 lb

This is a soil additive, mix shallowly into the soil at the drip line of the shrub, not the base. Mix in about three inches down. Apply when foliage appears. When using this product, water following the application. A slow-release food of this type is easiest to use on hydrangeas and other acid-loving plants, like blueberries. Expect larger blooms when using this all-natural brand. A second application may be used when blooms finish but is often not needed.

  • N-P-K Ratio: 7-3-3

  • Fertilizer type: Water mix

  • Amount: 1.5 lbs​

Use this for the bluest of blooms. This water-soluble food contains aluminum sulfate, the ingredient that makes the flowers bluer. Mix at one tablespoon per gallon and feed every two weeks for the first month. Apply onto damp soil. This product makes hydrangeas healthier and blooms may be larger and last longer. Acidity in the soil makes the blooms blue and this really perks up the color.

  • N-P-K Ratio: 4-3-4

  • Fertilizer type: Granules

  • Amount: 18 lbs

Specifically Formulated for acid-loving plants, mix this into the soil at the drip-line of the bush. Long-lasting, organic, often used by professional growers. A 4-3-4 NPK contains ingredients to makes the root system grow larger, leaves get greener and blooms grow larger and last longer. Available in a large bag for those with many acid-loving specimens. This is the best product for use in heavy clay soils, according to reviews.

  • N-P-K Ratio: 14-14-14

  • Fertilizer type: Granules

  • Amount: 8 lbs

For both indoor and outdoor plants, follow the directions and fertilize all of your acid-loving plants. Don’t mix, work into the top area of soil. Reviews rate this as a great product, possibly the best one we’ve included. Works with all types of plants. Eleven essential nutrients are included in this product. With a no-burn pledge when applied as instructed, one feeding lasts six months. Get the biggest blue blooms on your hydrangeas.

  • N-P-K Ratio: 9-8-7

  • Fertilizer type: Spikes

  • Amount: 30 Spikes

Jobe’s Tree and Shrub Spikes are perhaps the easiest way to feed your hydrangeas as well as Azaleas, Camellias & Rhododendrons. Simply place them in the ground around the root system in spring as the foliage begins to appear. If the ground is dry, moisten it before inserting them. The soil around hydrangeas should remain moist most of the time for best performance. These tree and shrub spikes provide a steady supply of nutrients to your shrubs.

How to Produce Beautiful Hydrangeas

Many of us grow hydrangeas and expect a lush and vibrant bush, full of summertime blooms. Proper fertilization can ensure our hydrangeas look their best. Grow these plants in rich, well-draining soil. Let’s look at a couple factors that you may want to look into when making an educated decision on deciding on a fertilizer to buy.

N-P-K Ratio

Generally, hydrangeas prefer fertilizers with an NPK ratio of roughly 1-1-1. Make sure to check out further details of what NPK ratio means in my other article.

Slow release nitrogen

Slow release forms of nitrogen provide a good form of nutrients for hydrangeas. Just make sure that if you are using granules that you actually cover the granules with soil otherwise they will not release properly.

Follow product instructions

Make sure to follow the fertilizer’s product instruction because over-fertilizing your hydrangeas can create just as many issues as under-fertilizing. If you give your hydrangea too much nutrients it will get something called leaf burn, where you will start to see the leaves looking like they are scorched. This is only a symptom of the deeper problem that the roots of the hydrangea are being damaged.

Wrapping it up

I hope you have found this useful. You cannot go wrong with any of the fertilizers above. Make sure to choose based on your needs rather than on price alone.

Happy Planting!

About the author: Carley Miller is a horticultural expert at TheGreenPinky. She previously owned a landscaping business for 25 years and worked at a local garden center for 10 years. Read More