When to Fertilize Hydrangeas in California (Best Time)

best time to fertilize Hydrangeas in California

Fertilization at key times is the key to success for vibrant and stunning blooms.

So, what is the best time to fertilize hydrangeas in California?

Early spring is a great time to start fertilizing your roses as the roses wake up from winter nap. Then, fertilize for the second time in summer before your hydrangeas bloom.

Here’s everything you need to know.

When to Fertilize Hydrangeas in California?

Best Time To Fertilize Hydrangeas in California

You must have nutrient-rich soil if you want plenty of blooms from your hydrangeas.

For that, we will fertilize them at these key stages:

  • Start your fertilization in early spring as your roses come out of dormancy.
  • Fertilizing right before your hydrangeas bloom will help to develop strong and vibrant blooms.
  • Stop applying fertilizer 6-8 weeks before the first frost date.

Now, you might be wondering why the fertilizing schedule differs for people.

Some fertilize once a month, while some do every two weeks. Both get stunning blooms. What’s the deal?

You must keep things simple.

Start your fertilization in early spring as your hydrangeas come out of their winter nap. Then, you can follow the schedule recommended by the fertilizer.

When To Fertilize?Why?
Early Spring:Start your growing season off with this fertilization to get the growth started.
Before blooming:Use a high phosphorus fertilizer to encourage vibrant blooms.

Let me explain this in detail.

Fertilize in Early Spring:

These early months of the growing season are extremely important for hydrangeas.

This is when the plant comes out of the dormancy stage.

At this stage, you should use a balanced fertilizer. For example, the 10-10-10 fertilizer.

Note: This number shows the NPK ratio of fertilizer. So, this fertilizer contains 10% nitrogen, 10% phosphorus, and 10% potassium.

When to Fertilize Hydrangeas in California

Now, you might be wondering why these nutrients are essential.

  • Nitrogen: It is important for leaf growth.
  • Phosphorus: It helps with fruit and flower production.
  • Potassium: It encourages strong stems and branches.

Remember that spring in California is mild and sunny. This makes it ideal for hydrangeas.

When you are done, move on to the next step

Fertilize in Summer:

Hydrangeas bloom primarily in the summer. However, some varieties bloom in the spring and fall.

So, this is a good time to apply fertilizer.

Here’s why.

This dose, right before your hydrangeas bloom, will help them to develop strong and vibrant blooms.

At this stage, you should use a fertilizer high in phosphorus. As I mentioned earlier, phosphorus is the nutrient that will lead to bigger and brighter blooms.

Note: You should delay this application until late summer for Fall blooming varieties. The idea is to fertilize hydrangeas just before they begin to bloom.

Generally, you should avoid fertilizing hydrangeas in the late Fall.

You should fertilize them when they are actively growing. So, fertilizer application at this stage is not recommended as hydrangeas prepare for dormancy.

Mulch in Early Spring:

Mulch (any material spread over the surface of the soil) retains moisture in the soil.

You should know that hydrangeas love plenty of water. As the weather is warm during spring in California, mulching will conserve the moisture in the soil.

Plus, it will also regulate the soil temperature.


You can also mulch in the fall season.

This is because the organic matter in the mulch breaks down to release minerals. This leads to healthier shoots.

Now, you might be wondering how to make mulch. We have two types of mulch.

  1. Organic mulch
  2. Inorganic mulch

Organic mulch can be made from bark, straw, grass clippings, and shredded leaves.

On the other hand, inorganic mulch can be made from gravel or plastic.

So, this was a general guide about fertilizing hydrangeas in California. Remember that we have different types of hydrangea.

Therefore, the fertilizing schedule varies slightly. Now, let’s talk about each of them in detail.

Popular Hydrangea Types:

There are multiple varieties of hydrangea.

Their flowers come in different shapes – From rounded and big flower clusters to conical flowerheads.

Let’s talk about the most popular types in California.

Bigleaf Hydrangea (Hydrangea macrophylla):


  • Color: Pink, white, blue, purple or red
  • Bloom time: June to October
  • Fertilizing: Feed them with a balanced fertilizer in early spring. Then, follow the recommended frequency by the manufacturer until growth slows in the late fall.

These hydrangeas bloom in late spring or early summer.

bigleaf hydrangeas in California

Their flowers are white, pink, blue, or red. Now the question is when to fertilize them.

The first fertilizer application should be in early spring. After that, feed them with additional fertilizer at intervals recommended by the manufacturer.

If you want pink flowers, use a fertilizer high in phosphorus. Alternatively, a fertilizer high in potassium and low in phosphorus can give you beautiful blue color.

This takes us straight to the next type.

Oakleaf Hydrangea (Hydrangea quercifolia):


  • Color: White to pink or purple
  • Bloom time: July to September
  • Fertilizing: Fertilize them in early spring.

Apart from the hottest southern regions and the coldest northern regions, you will find them throughout California.

This is because they can handle more sun, tolerate colder weather, and can tolerate some drought.

You should fertilize Oakleaf hydrangeas in early spring with a granular fertilizer formulated for trees and shrubs.

A fertilizer high in phosphorus will encourage good blooms.

when to fertilize hydrangeas in California

With this, let’s move on straight to the next type.

Smooth Hydrangea (Hydrangea arborescens):


  • Color: White to pink
  • Bloom time: June to September
  • Fertilizing: Once before the end of winter.

These shrubs are native to the US.

They are popular because of their nice foliage and big ball-shaped flowers.

You will find them throughout California because they perform well in warm and cool climates.

If I talk about fertilizing smooth hydrangeas, a basic spring and fall fertilizer will work great for them.

In most cases, smooth hydrangea should only be fertilized once before the end of winter.

Note: A fertilizer meant for acid-loving plants will work great as well.

It is essential not to over-fertilize. This is because over-fertilizing will eventually lead to weakened stems.

Panicle Hydrangea (Hydrangea paniculata):


  • Color: White
  • Fertilizing: Fertilize them only once in the spring. Over-fertilization can lead to weaker stems.

This low-maintenance hydrangea is popular throughout the US.

This type grows well in the North and South. It is comparatively more cold-tolerant.

The best part?

It has beautiful conical-shaped flowers.

If I talk about fertilizing them, less is more! You only have to fertilize them once a year.

Spring is the best time. You can use a balanced 10-10-10 fertilizer. A rose fertilizer will also be fine.

Types of hydrangeas

This takes us straight to the next point.

Climbing Hydrangea (Hydrangea petiolaris):

  • Color: White
  • Fertilizing: Fertilize them twice a year. Once in early spring (exactly before new leaves start to bud) and then in summer (when the flowers bloom).

This type of hydrangea is really interesting. Here’s why.

They have large fragrant clusters of white flowers, and they bloom in late spring and summer.

Note: They are suitable for zone 4-8. They do not thrive in zone 7.

I have a question for you. When to fertilize them?

You should fertilize them twice a year. The first application should be in early spring (exactly before new leaves start to bud). Then fertilize them again in summer when the flowers bloom.

For this, you can use a slow-release fertilizer or compost. So, here’s the summary:

Type of Hydrangea:When to Fertilize:
1. Bigleaf HydrangeaFeed them with a balanced fertilizer in early spring.
2. Oakleaf HydrangeaFertilize them in early spring.
3. Smooth HydrangeaOnce before the end of winter.
4. Panicle HydrangeaFertilize them only once in the spring.
5. Climbing HydrangeaFertilize them twice a year. Once in early spring and then in summer.

So, these were some popular types of hydrangeas.

How to Fertilize Hydrangeas?

The application process will depend on the type of fertilizer you use.

So, let’s discuss some options in this step-by-step guide.

Step 1: Conduct a soil test

While this is not mandatory when it comes to fertilizing hydrangeas, it is recommended.

This will help you make informed decisions by gathering information about your soil.

You will also learn about your soil pH. This matters if you want to change the color of your hydrangeas.

When you are done, move on to the next step.

Step 2: Choose a fertilizer

At this stage, you have two options:

  1. Inorganic Fertilizer
  2. Organic Fertilizer

Let me break this down for you.

Inorganic (Granular):

The first option is a granular fertilizer.

These (dry) fertilizers come in the form of pellets. Plus, they are usually slow-release.

The question is, how to apply granular fertilizer to hydrangeas?

First of all, read the instructions on the package.

When you know the amount, it is time to sprinkle the granules over the drip line. Now, scratch these granules into the soil.

Finally, water the soil. Over here, there is something that you should know.

How to Fertilize Hydrangeas in California

Add the fertilizer to damp soil (instead of dry soil). This will prevent root burn.

This takes us straight to the next topic.

Inorganic (Liquid):

This is the second option.

As the name suggests, this liquid solution contains nutrients for your hydrangeas.

First of all, dilute this liquid fertilizer with water. Now, slowly pour this solution directly on the soil and water simultaneously.

The idea is to make the soil damp (there should not be standing pools of water on the surface).

This fast-release option can be applied when hydrangeas are blooming. This will keep the blooms bright and colorful.

Now, let’s talk about some organic options.

Organic Fertilizers:

Organic fertilizers are great.

They feed microorganisms that allow hydrangeas to use the nutrients in the soil. This improves the bloom color.

Now, let’s take a look at some organic options.

  • Compost: An all-purpose compost works great for most hydrangeas.

Compost provides important nutrients and improves soil drainage.

You should spread 4-6 inches of compost around your established hydrangea in early spring.

In the hotter areas of California, you can feed them a second time in summer. But, you should not over-fertilize.

What makes compost great for hydrangeas is the balance of nitrogen, phosphorus and potassium.

So if you want beautiful blooms and strong stems, you should try this organic option.

Now, let’s move on to the next point.

  • Bone meal fertilizer: This organic option works well with hydrangeas.

As the name suggests, this fertilizer is made from animal bones. The high amounts of phosphorus and calcium promote large and bright blooms.

You should add the bone meal fertilizer in early spring before the first signs of growth.

Bone Meal Fertilizer for Hydrangeas

Note: Before adding bone meal, amend the soil to make it slightly acidic.

Generally, 3 cups of bone meal for 100 square feet of soil is recommended. After sprinkling it, rake it into the soil.

Finally, water the soil.

Related: Bone Meal Fertilizer For Peonies | Good or Bad?

Banana Peel Organic Fertilizer | Is it Good?

Will the Fish Emulsion Fertilizer Make Your Roses Bloom?

Related Questions About Hydrangeas:

Now, let’s take a look at some frequently asked questions about hydrangeas.

How do I get more blooms on my hydrangea?

The first tip is to keep the soil moist. If the soil lacks consistent moisture, the hydrangea will not perform well.

To keep the soil, you can add mulch around your hydrangeas.

The second tip is to provide the right amount of light. Over here, you have to take a balanced approach.

This is because too much sunlight is not recommended. So, hydrangeas prefer partial sun.

Ideally, full sun in the morning and then some afternoon shade will work great.

Finally, fertilize them at the right time.

Why is my hydrangea not blooming?

Let me share the 3 popular reasons why your hydrangea may not bloom.

1. Excess nitrogen.

If hydrangeas are fed with more nitrogen than potassium, they may skip flowering to grow more foliage.

2. Less water.

As we discussed earlier, your soil should be moist.

So, you should water your hydrangeas properly. If the leaves wilt in the heat of the day, they need more water.

3. Improper pruning.

Hydrangeas bloom on either old wood or new wood.

Note: Old wood refers to the growth from the previous season. New wood refers to the growth from the current season.

Bigleaf, Oakleaf, and Climbing hydrangea bloom on old wood. So, you should prune them lightly right after flowering.

Moving on, Panicle and Smooth hydrangeas bloom on new wood. So, you should prune them in late winter when they are coming out of dormancy.

If you prune your hydrangeas at the right time, you will have beautiful blooms.

Wrapping Up:

If you want a healthier hydrangea that produces fuller blooms, you have to fertilize it at the right time.

So, when to fertilize hydrangeas in California?

Generally, one application in early spring and the second right before they bloom is recommended.

However, the application rate may vary depending on the type of fertilizer you use.

Over here, let me tell you that you should not over-fertilize. In most cases, less is more!

More resources:

Best Time To Fertilize Roses in California

When to Fertilize Lawn in Florida | Detailed Guide

Fertilizing Mango Trees in Florida | When and How to

Amelia James

Hey there! I’m a gardening enthusiast from Dallas, Texas. I have been gardening for over five years now. I’m excited to share everything I’ve learned. So, let’s dig in and have some fun!

When to Fertilize Hydrangeas in California (Best Time)

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