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Which fertilizer for hydrangeas is best?

Some hydrangeas are bright white while others sport lovely hues of pink, blue, red or purple. Regardless of the color, the large blooms are a beautiful addition to any yard or garden.

Don’t let the intricate flowers intimidate you, because hydrangeas are actually fairly easy to grow. And the right fertilizer will help your plants stay healthy and produce beautiful blooms throughout the growing season. Southern Ag 20-20-20 All-Purpose Granular Fertilizer is a top fertilizer that will work for any hydrangea.

What to know before you buy fertilizer for hydrangeas 

Whether you already have hydrangeas blooming on your property or are planning to add some to your garden or landscaping, understanding these beautiful plants and their needs will make it possible for them to produce their signature flowers year after year. 

What a hydrangea is 

Hydrangeas are perennial flowering plants known for their large, globe-like blooms. They are hardy and do well in most regions when placed in areas that aren’t extremely sunny or shady. They also thrive in soil that gets adequate moisture and has decent drainage. 

There are more than 75 species of hydrangea, with bigleaf, climbing, smooth, panicle, Japanese, oakleaf, tea of Heaven and French among the most popular varieties. In addition to the gorgeous flowers, the plants are also beloved for their long blooming period that typically lasts throughout spring and summer, and sometimes into the fall. 

The nutrients hydrangeas need 

Just like many other types of flowering plants, hydrangeas benefit from garden fertilizer that replenishes soil with important nutrients. However, the best formula to use is one that’s either formulated for hydrangeas or has a nutrient ratio that meets their specific needs. 

Caring for hydrangeas

It’s best to plant hydrangeas in the fall or early spring. Both seasons give root systems time to develop in preparation for the plants to grow and bloom.

Pruning existing plants should be done after they have finished blooming in late summer, but before buds for the following year begin to develop.

Mid to late spring is the best time to apply hydrangea fertilizer to provide nourishment for the upcoming growing season. Unlike some other plants, hydrangeas do not benefit from fertilization in the fall because they go dormant during the winter. Adding fertilizer late in the year may result in growth that isn’t likely to survive cold winter conditions. 

What to look for in a quality fertilizer for hydrangeas 

NPK for hydrangeas

Fertilizer content is measured in ratios of nitrogen, phosphorus and potassium. Hydrangeas do well with a balanced level of these three vital nutrients, so fertilizer with an NPK rating of 10-10-10 or in that range is a good option. For plants that need help with bloom production, extra phosphorus is required. For example, 10-20-10 NPK fertilizer will create a multitude of large flowers throughout the growing season. 

Soil pH

Generally speaking, hydrangeas do well in neutral or acidic soil. However, blue, pink, red and purple blooms have varying requirements to bring out vivid shades. 

Blue flowers need highly acidic soil with a pH of 5.5 or lower to achieve an eye-catching hue. The color of pink and red blooms is at its best with a pH level of 6.5 and above. Hydrangeas with purple blooms need a soil pH between 5.5 and 6.5. Performing a soil test will help you determine if the pH level is ideal for your hydrangeas. 

Types of fertilizer 

Fertilizer for hydrangeas is available in liquid, granular, powdered or spike forms. Liquid fertilizer comes ready to use, or in concentrated formulas that must be mixed with water before applying it to the soil. Granular fertilizer is designed to be sprinkled for time-released nutrients. Spikes also release nutrients slowly for targeted plant nourishment.

Synthetic and organic fertilizer 

Similar to fertilizers for other types of plants, those that are ideal for hydrangeas come in synthetic and organic formulas. Synthetic fertilizer is made with lab-created chemicals, while organic is made with natural ingredients such as compost or bone meal. Both work well at producing strong flowers and big blooms, so the choice between the two is up to the gardener’s preference. 

How much you can expect to spend on fertilizer for hydrangeas

It will cost $9-$25 to buy enough for several plants or multiple applications. 

Fertilizer for hydrangeas FAQ

Will a specific type of fertilizer change white hydrangea blooms to pink or blue?

A. No, white hydrangea blooms will stay white regardless of the type of fertilizer you use. Certain fertilizers will enhance the color of blue, purple, red or pink hydrangeas. 

My hydrangea plant isn’t looking very healthy. Should I apply fertilizer more frequently than recommended?

A. This isn’t a good idea, because too much fertilizer can damage the plant’s root system. For best results, stick with using fertilizer in the spring or as directed on the packaging, and consider trying a formula with high levels of phosphorus for better blooms.

What’s the best fertilizer to buy for hydrangeas?

Top fertilizer for hydrangeas

Southern Ag 20-20-20 All-Purpose Granular Fertilizer

Southern Ag 20-20-20 All-Purpose Granular Fertilizer

What you need to know: This is a balanced plant fertilizer suitable for any type of hydrangea. 

What you’ll love: This formula offers a 20-20-20 NPK rating that provides balanced nutrients that hydrangeas need. Its granular form makes it easy to use. 

What you should consider: While this product is highly effective, using it as directed is vital to prevent over-fertilizing that may damage plants. 

Where to buy: Sold by Amazon

Top fertilizer for hydrangeas for the money

Soil Acidifier for hydrangeas

Espoma Soil Acidifier 

What you need to know: If you’re looking for fertilizer that will make your blue hydrangeas bright and colorful, this is the one to buy. 

What you’ll love: With a formula high in acid, it’s ideal for lowering the pH score of soil and creating ideal conditions for blue blooms. 

What you should consider: This fertilizer isn’t as versatile as some competitors, as it isn’t the best pick for hydrangeas that don’t require extremely acidic soil.  

Where to buy: Sold by Home Depot and Amazon

Worth checking out

Pendelton Triple 10 All-Purpose Fertilizer

Pendelton Triple 10 All-Purpose Fertilizer 

What you need to know: This liquid formula contains important hydrangea nutrients, and is a good choice for multiple plants when mixed as directed. 

What you’ll love: It’s a liquid fertilizer that contains seaweed extract rich in nutrients. The 10-10-10 NPK formula is highly concentrated for multiple applications. 

What you should consider: Care must be taken to dilute this fertilizer properly; otherwise it could damage plants. It also has a strong fishlike odor. 

Where to buy: Sold by Amazon 


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Jennifer Manfrin writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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