The varieties of Azalea plants grow true from seed. Hybrids Azalea plants are crosses between other species. It can also be reproduced from cuttings, which are clones of the mother plant.
Established Azalea plants do well without any additional fertilizer. This will be true if the Azalea plants are kept well mulched. The hummus from the mulch gives proper nutrients and promotes the presence of mycorrhizal fungi to bring soil nutrients to the roots.
Applying inorganic Azalea fertilizers decreases the appearance of mycorrhizae, which increases the need for higher levels of nutrients.
What is the best Azalea fertilizer?
Regular all-purpose fertilizers may not be appropriate in giving Azalea plants (Rhododendron) with the specific and particular nutrients the plants need. A fertilizer designed especially for the Azalea plant (Rhododendron) or for acid-loving plants provides your acid-loving plants with the necessary essential nutrients they need.
A good option would be fertilizer with a blend of nutrients that includes added sulfur to help keep soil pH optimal as the fertilizer feeds. The fertilizer must also contain calcium, iron, and magnesium to avoid nutrient deficiencies.
Any Rhododendron fertilizer should be used right away and continue to feed Azaleas for months.
Before using Rhododendron fertilizer in your garden, get your soil tested. The soil test results will show the current amount of all the essential nutrients.
The result will give recommendation types and amounts of fertilizer needed for the Azalea plant you plan to grow.
List of the best fertilizer for Azalea
The Espoma Organic Holly-Tone Plant Food has the NPK formulation of 4-3-4 with added Calcium (3.0%), Magnesium (1.0%), Sulfur (5.0%). It comes with bio-tone microbes that slowly break down the food for the plant to have steady and continuous feeding.
While providing Azalea plant nutrients and maintain its color, this fertilizer product helps plants healthy and beautiful. This product is all-natural and has safe ingredients that are low in salt and will not burn the soil.
There is no need for mixing and leaves no mess in any outdoor setting. Azalea, evergreens, and other acid-loving plants will result in prominent blooms and deeper roots.
For new plantings, dig one hole twice wider with the same depth as the root ball. Dugout about 1/3 of the soil and immediately replace it with humus, peat moss, or compost.
Mix about one cup of this fertilizer into the soil. Place the plant and fill the hole halfway with soil. Pack the soil firmly.
Water the plant and allow it to settle. When you are finished filling the hole, leave the top two inches loose to absorb water quickly.
Make depression around the plant to hold water. Add mulch to control weed, slow down evaporation, and conserve water. Water well until the plant is established.
This Miracle-Gro Water Soluble Azalea, Camellia, and Rhododendron Plant Food is an exceptional plant food designed for acid-loving plants. It is an excellent choice for plants like azaleas, tall evergreen, rhododendrons, camellias, dogwoods, magnolias, gardenias, and orchids.
The fertilizer contains several vital nutrients and rich in iron. You can apply this fertilizer for Azalea every one to two weeks.
You can apply using your watering can, and feeding every week means abundant blooms, vibrant color, and lush foliage. You must follow the manual direction so it will not harm other plants or burn foliage.
All you need to do is to add the fertilizer to your watering can with one tablespoon of Miracle-Gro for one gallon of water (for outdoor Azalea). Or mix 1/2 teaspoon per one gallon of water for indoor Azalea.
After that, you can start to feed the Azalea plant as well as water them well.
3. 3M Company Voluntary Purchasing Group INC Hi-Yield Azalea, Camellia, Gardenia, Evergreen Fertilizer
This Azalea fertilizer has an NPK formulation of 4-8-8. It is an excellent choice for providing food for Azalea, camellia, and gardenia as well as evergreen.
It is specially formulated plant food to help produce nutrient healthy roots, stems, leaves, and flowers on acid-loving plants. This fertilizer will allow the buds to appear, and the leaves remained green.
You can use this fertilizer for new and established plants.
The VPG fertilizer has an NPK formulation of 9-15-13 that consist of balanced plant food with added vital trace elements. The active ingredients are potassium chloride, respirable quartz, attapulgite, dolomitic limestone, monoammonium phosphate, and ammonium sulfate.
These ingredients are the perfect combination for acid-loving plants, and it means creating an acid growing condition. The condition will provide Azaleas, camellias, and gardenias to grow and thrive well.
The potassium chloride is an excellent source of potassium, which helps Azalea plants having disease resistance, increase plant vigor, and helps stiffen steams.
Apply 1/4 cup for every two feet of Azalea plant height. Feed the Azalea plant at least three times during the Azalea plant growing season.
This fertilizer also helps control soil acidity for an acid-loving plant such as Azalea. The fertilizer works to provide proper plant nutrients to do well.
The Dr. Earth Acid Lovers dry fertilizer is formulated for acid-loving plants that are an excellent option for Azaleas, blueberries, evergreens, ferns, shade plants, camellias, rhododendrons, maples, hollies, gardenias, and hydrangeas. You can apply this fertilizer in raised beds during transplanting.
It is also an excellent option to fee Azalea plant during mid-season for a nutritional boost. The fertilizer is handcrafted from feed grade ingredients.
These ingredients are enriched with organic nutrients, including mined minerals, fish bones, fish, land plants, and ocean plants. This organic, nutritionally balanced formula promotes healthy soil and nutrient-rich soil to grow the most vigorous Azalea plants.
Healthy soils can grow the healthiest flowering plants, vegetables, and fruits in your garden, backyard, and home. You can expect a maximum bulb size and potential color when you apply in mid-season for a continuous supply source of nutrition.
You can keep the plants strong and healthy by feeding every forty-five days. It is a safe fertilizer, and it is OMRI listed as well as CDFA OIM registered.
This Dr. Earth Acid Lovers Rhododendron Azalea Camellia Fertilizer produces outstanding results because the nutrients in the ingredients are released quickly as well as to continue feeding for several months. This scientific ultra-premium formula offers optimum levels of primary essential nutrients needed by acid-loving plants, including micronutrients and multi-minerals.
It is infused with ProBiotic that contains eight chosen strains of endo, ectomycorrhizae, and beneficial soil microbes. These ProBiotic increase drought tolerance, increase Azalea plant performance and improve nutrient availability.
ProBiotic does its job to ensure that the organic nutrients are completely broken down and quickly released into the soil to be absorbed by the plant roots.
This superior fertilizer formula builds strong and superior bushes, good soil health, and more abundant as well as more extensive colorful flower blooms.
This Miracle-Gro LiquaFeed Flowering Trees and Shrubs Plant Food is a liquid fertilizer that is specially formulated to feed your Azalea plants and any other acid-loving plants such as camellia and gardenia plants as efficiently as watering them. Its ingredients, including essential nutrients to stimulate their growth and produce healthier as well as lovelier shrubs and flowers.
You can use this fertilizer for containers or in-ground acid-loving plants. To get the expected result you want, You are recommended to feed the Azalea plant every seven days or 15 days.
One bottle of 16 oz can cover up to 400 square feet. The NPK formulation of this fertilizer is 9-3-3. All you have to do is to pour the liquid fertilizer on the soil at the base of the Azalea plant.
Down To Earth’s Acid Mix is a fertilizer with NPK formulation of 4-3-6 that is formulated for Azalea and other plants to thrive in low-pH soil. Other acid-loving plants such as blueberries, raspberries, rhododendrons, hydrangeas, evergreen shrubs, and trees love this fertilizer.
The best time to apply this fertilizer is in early spring to get lush flowers and fruit. Re-apply again when blooms appear.
You can also apply this fertilizer for Azaleas in fall months to stimulate and promote root growth and boost resistance to colder temperatures.
Besides the NPK formulation, the fertilizer is blended with sulfur, calcium, and magnesium. These essential nutrients and minerals are derived from kelp meal, fishbone, cottonseed meal, fishbone meal, langbeinite, and rock phosphate.
The fertilizer also contains non-plant food ingredients (2.5%) of humic acids derived from Leonardite. One benefit of humic acid has been the aggregation of soil. This aggregation made the soil softer, more porous, more aerobic, with better drainage, resulting in more profound root growth of all plants, especially Azalea.
When is the best time to fertilize Azalea plants?
The best time to fertilize established Azalea plant is in early spring or late fall. You can re-apply the fertilizer in three months to four months later.
By practicing this, you provide the nutrients they need for the year. You can broadcast the fertilizer over the area under your shrubs.
Water the entire area thoroughly after the application. To make it easier, you can use the liquid form fertilizer for the Azalea plant.
Azalea plants with shallow roots are sensitive to overfertilizing, so follow label instructions.
If you do fertilize, it is best to apply it between late fall and early spring when the Azalea plants are dormant. Do not fertilizing after June.
How to prevent nutrients deficiencies in Azalea plants
You may notice nutrient deficiencies in a particular part of the Azalea plants. The most common problem is chlorosis when there is yellowing between the leaves’ veins while the threads remain green.
This yellowing may be the cause of a lack of available iron. Other causes may be compacted soil, overwatering, overfertilizing, or soil acidity outside of the range needed by Azalea plants.
The right soil pH for Azalea plant should be between a low of 4.5 and a high of 6.0, where 7.0 is neutral).
While you are trying to fix this problem by spraying liquid chelated iron, that does not solve the underlying problem. If you see only one plant with the problem, try moving it.
After moving the plant, take a look at the roots and the soil. Check the general soil looseness and soil drainage.
Try fixing the soil looseness problem by loosening heavy soil. You can add about 50% of composted leaves, beautiful pine bark, or any of the other organic material products for use as mulch.
To lower the pH (which means to increase the soil acidity) sprinkle two handfuls of ferrous sulfate around the base of the plant. Azalea plant does not like aluminum sulfate, and it is toxic to Azalea plants.
To raise the pH (which means to decrease the soil acidity), sprinkle two handfuls of oyster shells or ground dolomitic limestone around the plant. Avoid using hydrated lime, that mau burn the Azalea plant.
Other ways to raise the pH are using wood ashes and adding micronutrients, potassium, and phosphorus.
1. Nitrogen deficiency
When you notice stunted Azalea plant growth, small new leaves, and yellowish leaves could be the sign of a nitrogen deficiency. To fix the problem, use a fertilizer that will not reduce the soil acidity. Use fertilizer with ingredients including well-rooted manure, ammonium sulfate, and ammonium nitrate
2. Calcium deficiency
Once you notice that your Azalea plant has twisted leaf tips and leaf tip burn, this could be a sign of a calcium excess or calcium deficiency. You can fix this problem by applying ground oyster shells, gypsum, and dolomitic limestone. Gypsum will not affect the soil acidity, while oyster shells or limestone will also raise the pH (which means less acidity), which may not be desirable.
3. Potassium deficiency
A potassium deficiency will cause leaf tip burn, inward curling of the leaves, and premature leaf drop to the Azalea plant. Fix the problem by spraying with chelated iron, and sprinkling a small amount of potassium sulfate around the plant will have a longer-lasting effect.
4. Phosphorus deficiency
Your Azalea plant will suffer from unusual and flat deep green leaves when having severe phosphorus deficiency. They turn reddish-brown leaves and purplish-brown leaves to eventually fall off.
While a mild deficiency may result in reduced flowering and lighter flower colors. To correct a phosphorus deficiency apply diammonium phosphate so the phosphorus migrates rapidly.