Skip to main content

When should you fertilize your azaleas? What you need to know

Azaleas are a shrub with beautiful flowers that range from purple to white. They’re a very popular plant to include in gardens or bordering walkways. Azaleas, while not the most difficult plant to care for, do have some particular needs. Figuring out when the best time to fertilize your azaleas is, how much fertilizer to use, and what kind of fertilizer to get can be a chore. So let us do it for you! In this handy guide, we’ll lay out a few factors that go into determining the best time to fertilize your azaleas and include a few tips for picking out a good fertilizer.

Yellow azalea flowers

What kind of fertilizer do azaleas need?

All plants need the same basic nutrients, just in different amounts. Nitrogen, phosphorus, and potassium are the three nutrients needed in the largest amounts, while iron, boron, zinc, calcium, magnesium, sulfur, copper, manganese, and molybdenum are typically needed in smaller amounts, although they’re just as important.

The overall nutritional needs of a plant are usually met by the soil, but in poor soils or soils that happen to be lacking in a particular nutrient, fertilizer can help keep your plants well-fed. Specific fertilizers are also used to add extra nutrients into the soil, usually aimed at increasing the overall plant size or the size and brightness of blooms. For these, nitrogen and phosphorus-rich fertilizers are preferred. Before adding fertilizer to your soil, you should test it to see what nutrients it may be low on, to make sure to target those and to avoid adding too much of any one nutrient to the soil.

Azaleas grow specifically in acidic soils. Due to this, any additives you put into the soil runs the risk of changing the soil pH, either by neutralizing it or by making the soil too acidic, depending on the contents of the fertilizer. It’s best to use slow or controlled-release fertilizers, since the more gradual integration of the fertilizer decreases the risk of a sudden change in soil pH.

White azalea flowers

Azalea variety

Azaleas all need the same general nutrients, so you may think that azalea variety doesn’t play a role in determining when to fertilize your plants. However, azalea variety does have an impact, as not all varieties of azalea bloom at the same time. The best time to fertilize your azaleas is in spring, either during or just after their bloom. It’s best to avoid fertilizing them at the very beginning. Wait until the shrub has formed several flowers, rather than adding fertilizer at the first sign of buds opening. Depending on their variety, azaleas can bloom during any month from February to September.

A bush of light pink azaleas


Climate is important for two reasons. The first is that climate can affect bloom time. Azaleas generally bloom in warm weather. If you live in a climate with a mild winter and an early spring, then you may see azaleas blooming sooner than you might expect. Many azalea varieties will bloom again in late summer or early fall. In cooler climates, however, this second bloom may come earlier, last for a shorter period of time, or not happen at all.

Climate is also important to keep in mind if you live in an area with dry springs or summers. Fertilizers are absorbed more readily when the soil is moist. In regions with regular rainfall, this mostly means waiting until after it’s rained to fertilize your azaleas. In drier regions, however, you may need to water your azaleas manually before you add the fertilizer.

Bright pink azaleas


When you first plant your azalea, it’s a good idea to let it get established in your soil without any additives. It’s also extremely easy to over-fertilize young plants. For this reason, it’s best to avoid fertilizing your azaleas during their first year. If they need a boost in nutrients, consider adding a small amount of compost to your soil instead of fertilizer. Once your azaleas are in their second blooming season, you can begin adding fertilizer.

Now you know everything there is to know about when to fertilize your azaleas. After their first year, during or just after their spring bloom, when the soil is moist, add some slow release or controlled-release fertilizer. It’s a good idea to test your soil beforehand, though, so you can be sure you’re giving your azaleas exactly what they need.

Editors' Recommendations

Cayla Leonard
Cayla Leonard is a writer from North Carolina who is passionate about plants.  She enjoys reading and writing fiction and…
Quaking aspens are tall, beautiful, and easier to care for than you might expect
Read here and learn how to grow quaking aspens
Quaking aspen trees

Quaking aspens are native deciduous trees with striking and easily recognizable silhouettes. They have tall, thin trunks wrapped in white or silver bark. Although they are stunning all year long, with small white flowers in the spring and round green leaves in the summer, quaking aspens are perhaps most famous for their brilliant gold color of fall foliage. In addition to their beauty, quaking aspens are also extremely good for the environment. If you’re thinking about planting a quaking aspen tree in your yard, this is the care guide for you.
How to plant a quaking aspen
When choosing your planting site, there are a few key things to look for. First, your planting site should be well away from power lines, buildings, or other structures that tree growth could damage. Quaking aspens typically grow to between 30 and 50 feet tall (although some can grow much taller) and their longest branches can grow up to 30 feet long, so make sure your tree has plenty of room.

Your location should also be in full sun with rich, moist soil. Quaking aspens need at least 4 to 6 hours of sun each day in order to grow properly. In addition to the sun, a quaking aspen needs plenty of water and nutrients. Adding compost to your soil before you begin planting can help improve poor soil. Although it needs moist soil, avoid planting your quaking aspen in wetlands or dips where water pools, as too much standing water can lead to fungal infections.

Read more
Blazing stars will fill your summer garden with color: A liatris care guide
Growing and caring for liatris
Tall purple liatris (blazing star) with butterflies

There are many wonderful plants you can add to your summer flower garden for stunning color, from tall and bright sunflowers to short and sweet zinnia. If you’re planning your garden now, you should definitely consider adding liatris, also called blazing star, to the mix! This tall, drought-tolerant, native perennial has stunning purple flowers. It’ll even attract butterflies. Here’s everything you need to know about planting and caring for liatris.
Planting liatris
You can plant liatris bulbs in the spring or fall, but you can transplant mature plants during any season. Choose a location with full sun and well-draining soil to plant your liatris in. Blazing stars can tolerate some light shade, but they won’t thrive unless they get at least 6 hours of sun each day. Spacing is important when planting liatris, as they can grow to 2 feet high and 1.5 feet wide. Plant your liatris bulbs 12 to 15 inches apart so they have plenty of space to grow.

In addition to having well-draining soil, it should also be average or poor. Many plants prefer soil that's rich with organic matter, but liatris has an unusual quirk! The flower stalks will sometimes bend or flop over if the soil is too rich.

Read more
Take advantage of hydrangeas’ color-changing quirk – how to get beautiful blue hydrangeas
Make your soil acidic to turn your hydrangeas a beautiful blue color
Hydrangeas with blue flowers

Hydrangeas are known for two things -- impressive, showy flowers and their tendency to change color based on the pH of the soil. This makes them highly appealing, but also unpredictable. If you don’t take the soil into account, your bright blue hydrangeas could turn out to be pink or purple instead. With careful planning, you can take advantage of this quirk to ensure your hydrangeas are the striking shade of blue you want them to be.
Getting started
First, check what variety of hydrangeas you have. Not all hydrangeas change color! Bigleaf hydrangeas, especially the mophead and lanceleaf cultivars, are the ones that change color. However, white hydrangeas of any variety will not change color.

Test the soil’s pH before you get started. This lets you know how much you’ll need to change it, or if you need to change it at all. If your soil pH is already between 5.5 and 4.5, it’s acidic enough to turn your hydrangeas blue.

Read more