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How to Fertilize a Magnolia Tree

Magnolia trees are native to both the eastern US and southeast Asia. Fairly easy to grow and not a big attractor of pests, magnolias are ideal plants for landscaping. The trees produce large green leaves and attractive flowers. While fertilization is not absolutely essential to the growth of a magnolia tree, properly fertilizing the plant will help it thrive.

Plant the magnolia tree into the native soil of the area and water the soil thoroughly. Cover the base of the trunk with 3 to 5 inches of mulch, but do not fertilize until the magnolia has established itself on the land.

Use an acidic liquid fertilizer on a magnolia tree every few months for the first 3 years of growth. In the first growing season, use 1 cup of fertilizer around the planting circumference of the planting hole in March, May and July.

Increase the amount of fertilizer to 2 cups in the second year. Start at the edges of the tree’s canopy and spread the fertilizer outward to 3 feet beyond the canopy’s edge in March, May and July.

Up the amount of fertilizer to 4 cups in year three. Spread the fertilizer from the canopy’s edge outward 6 feet.

Place granular, slow-release fertilizer at the base of the magnolia tree a few times throughout the tree’s growing season after the first 3 years. At this point, the magnolia tree should have established a wide root system and be able to find most of its own nourishment in the soil.

Fertilize A Japanese Magnolia

Fertilize the Japanese magnolia tree in the late winter before new growth starts. Round the measurement to the nearest inch. Convert the radius measurement from inches to feet by dividing the measurement by twelve. Multiply the new radius by itself. For example, if the radius is 36 inches then divide 36 by 12 to get a radius of 3 feet. Apply an 8-8-8 nitrogen, phosphorous, potassium slow-release fertilizer at a rate of 1 pound per 100 square feet. Multiply the figure by your square footage to get the number of pounds of fertilizer you will need. Measure out the correct amount of fertilizer. Broadcast the fertilizer granules evenly in a 3- to 6-foot-wide ring just outside the Japanese magnolia's canopy. Water the area thoroughly to activate the fertilizer.


Choose a fertilizer for your magnolia trees that contains equal amounts of nitrogen, potassium and phosphorous.

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