Most ornamental plants need nutrition. This is because they have different characteristics from wild plants, such as abundant flowering. Usually, such features require additional nutrition.
Quick tips on how to fertilize magnolia
- Fertilize magnolia in early spring.
- Use a slow-release granular fertilizer with an NPK ratio of 12-4-8.
- Dig 2-3 holes around the trunk 2 inches deep. The distance from the holes to the trunk should be 1 foot.
- Apply fertilizer to the holes around the magnolia. Spread the manufacturer’s recommended amount of pellets evenly between the holes.
- Backfill the holes with soil and water the magnolia with 1-2 gallons of water.
This is a shortlist of steps on how to apply the fertilizer and we will go over them in more detail below. Also, be sure to check out the Basic Guide to Growing Healthy Magnolias.
When to fertilize?
The best time to apply slow-release fertilizer is March-April. It needs to be warm but the tree has not yet entered its active growth phase.
Choose a fertilizer that lasts at least 3-4 months. In this case, the magnolia will be nourished for the entire growing season. You also won’t have to apply anything extra.
If you use a liquid fertilizer or an immediate release fertilizer, follow the directions on the label. It must be said though that the efficiency of such fertilizers is lower.
Do not apply the slow-release fertilizer later than the first half of summer. Especially don’t do it in the fall. This is because the magnolia can stay active through the winter and will definitely suffer frost damage.
How to fertilize?
You have to use the right fertilizer to get good results. Slow-release pellets with an NPK ratio of 12-4-8 are the best. That is, the product should contain more nitrogen than phosphorus and potassium.
Make sure the fertilizer contains at least some magnesium and iron. Also the longer the action time of the pellets the better.
Dig 3 small holes around the magnolia up to 2 inches deep at equal distances from each other. The distance between the holes and the trunk of the magnolia should be at least 0.5 feet but no further than the drip line of the tree.
Dig the holes very gently to avoid damaging the root system.
Take the amount of fertilizer recommended by the manufacturer and spread it evenly between the holes. Cover the holes with soil.
Next, water the magnolia with 1-2 gallons of water or more if it is large. Nothing more is required of you, the pellets will do the job all season long.
In addition to mineral fertilizer, you can also use organic fertilizer. They can be applied together without any negative consequences.
Among the whole range of organic matter that is used as fertilizer, compost works best. The main thing is that it should be of high quality and free from pests and pathogens. To get this quality, buy this product only from reliable suppliers.
The first time compost should be applied to the planting hole before planting the magnolia. Mix 1-2 buckets of compost with the native soil in the planting hole.
After planting, mulch the root zone with a 2-3 inch layer of compost. Do not put mulch on the trunk of the magnolia, that is, avoid so-called volcano mulching.
Every year in the spring, the compost mulch should be renewed.
Over-fertilization is possible if fertilizer is applied too often or in too large portions. This will result in salt accumulation in the soil, causing damage to the root system.
The outward sign of excess minerals is a browning of the leaves. This usually occurs along the edge of the leaf.
It is also possible that the leaves will grow vigorously in the beginning but after a while, they will droop because the petioles will not be able to support their weight.
To remedy the situation, water the magnolia with 5 to 6 gallons of water. This will flush out some of the salts from the root zone. Repeat this watering after 1 to 2 weeks.
Also, replace the top 1-2 inches of soil around the roots if possible. Be as careful as possible not to damage the roots.
From now on, fertilize the magnolia no more than twice a year, regardless of the type of fertilization. The last fertilization of the year should be done no later than mid-summer.
Not enough nutrients
If your soil is more or less nutritious, the Japanese maple should not be deficient in micronutrients even if you do not fertilize it. However, there are cases where the maple will suffer without fertilization.
The first is poor sandy or clay soil. Here, the maple may not have enough minerals and will grow very slowly.
In this case, you should definitely improve the soil with organic matter before planting. Also, fertilize the maple at least once a year.
The second case of fertilization deficiencies is when the soil is too alkaline. If the pH>7.0, the nitrogen may not be available to the root system. As a result, the leaves will turn yellow.
To remedy this buy a soil pH test kit and find out what kind of soil you have. If the soil is too alkaline (pH>7.0) acidify it with garden sulfur or other commercially available acidifiers. Then follow the fertilizer recommendations above.