Find details on how to fertilize a magnolia tree and the best fertilizer for magnolia trees for magnolias including Little Gem magnolia tree. The fertilizers for magnolias given here is good for different types of magnolias including magnolia Grandiflora, ever green little gem magnolia, Southern magnolia, Japanese, Port wine and deciduous magnolias.
Fertilizing magnolias will help them to thrive and bloom throughout the year. The following picture shows a flower on my Little Gem magnolia grown from a cutting (Growing magnolias from cuttings) in Sydney, Australia, now growing in a pot.
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| Magnolia flower on a magnolia plant propagated from a cutting |
magnolia tree care | How to grow magnolia in containers | How to care for magnolias | growing magnolia tree from seeds
BEST Fertilizer For Magnolia Trees
Magnolias are not heavy feeders. Nitrogen is an important fertilizer for magnolias [1, 2] . Magnolia tree requires fertilizer high in Nitrogen and Potassium. It needs nitrogen to maintain its vigorous green foliage growth. It needs high potassium for flowers.
The best fertilizer for magnolias is that which contains more nitrogen (N) - about 2 times than potassium (K), and potassium at least 2 times of phosphorous (P).
You can feed N-P-K 12-4-8 or 16-4-8 or 20-5-10 formulation. I have used a Fruits and Citrus Fertilizer which has N:P:K = 8.8%, 1.4%, 8.7%, and my magnolias are growing vigorously with lots of flowers in containers and garden.
How Much Fertilizer For a Magnolia Tree?
In general, you can feed 45 gram (1/10th pound) of nitrogen for every inch of trunk diameter of your magnolia tree.
Calculate the Nitrogen required for your magnolia tree depending on its trunk diameter.
Let us calculate for NPK= 20:5:10 fertilizer/
Nitrogen 45/(20/100) = 45/0.20 = 225 gram
So you have to feed 225 gram of 20:5:10 fertilizer for 1 inch of trunk thickness. So if you feed 225 gram of this fertilizer, your magnolia tree will get
In 225 gram of 20:5:10 fertilizer
Nitrogen = (20/100)x225 = 45 gram
Phosphorus= (5/100)x225 = 11.25 gram
Potassium = (10/100)x225 = 22.5 gram
| NPK | 20:5:10 | 16:4:8 | 8.8:1.4:8.7 Citrus Fertilizer |
| Amount (g) | 225 | 280 | 500 |
| N(g) | 45 | 44.8 | 45 |
| P(g) | 11.25 | 11.2 | 7 |
| K(g) | 22.5 | 22.4 | 45 |
The table shows that lower the NPK ratios, more amount of fertilizer is needed to feed 45 gram of nitrogen.
Nitrogen deficiency will retard the growth of your magnolia tree. But if you feed too much nitrogen, it can cause the burning of foliage, the tips of the leaves will start burning.
When to Fertilize Magnolias?
The best time to fertilize your magnolia tree is early spring before new growth begins. After that you can feed a liquid fertilizer like Powder feed NPK=12 : 1.4 : 7 every 3 week till the end of Autumn to stimulate flowering and to promote disease resistance and root development.
Powerfeed fertiliser contains active liquid composts which stimulates flowering and fruiting, improves soil structure, boost plant growth, and help break down clay and reduce nutrient losses in sandy soils.
How to Fertilize Magnolias?
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| Fertilize your magnolia tree 1.5 feet away from the trunk to the drip line, between the white lines |
- Do not fertilize your magnolia during the first year after planting.
- First remove the grass or around the tree.
- Feed 1.5 feet away from the trunk to the canopy or drip line of the tree between the white lines shown in the figure. Spread the fertilizer on the surface and mix in soil.
- If growing in a pot, always feed away from the trunk, about 6 inch.
- Always water well after fertilization of your magnolias.
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| Fertilizing magnolia tree in a container Feed near the rim of the pot away from the trunk |
The iron deficiency in soil is indicated if the new leaves on your magnolia are smaller than normal having green veins against pale yellow background. Add chelated iron as per the recommendation on the label.
Proper Soil for Magnolias
It is important to know that the magnolia tree will absorb all of the nutrients from the fertilizer only in the soil with a pH between 5 and 6. If the soil pH is not right, then the soil will not absorb the nutrients from the fertilizer you feed, and the tree will not grow properly.
If you are planning to plant a new magnolia tree, then it is better to test the soil pH 3 months before you plant the it and amend it, if not correct. If the soil is acidic or pH is less than 5, then add Dolomite or Garden Lime in the soil. If the pH is alkaline or pH more than 6, then add garden sulphur in the soil. If your magnolia is already growing in a pot or garden, then check the soil pH periodically.
Video on how to fertilize magnolias
How to fertilize magnolias youtube video
How to propagate a magnolia tree youtube
magnolia propagataion from cutting, flowering in 2 years
repotting magnolia tree youtube video
Grow magnolias in containers youtube video
How to prune magnolia little gem
How to plant magnolia little gem
How to propagate magnolias by air layering
References
- North Carolina State University Cooperative Extension: A Gardener's Guide to Fertilizing Trees and Shrubs
- University of Flroida IFAS Extention: Magnolia Publications