How to Grow Magnolia Tree
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How to grow magnolia tree depends on three things: the species you buy, the season you plant, and how lightly you prune the young tree. The three pages below cover southern magnolia, Magnolia grandiflora, in most of their detail, and one of them is a general guide to new magnolia trees. The sources agree on sun, drainage and a light touch with pruning. They disagree on the best planting season and on soil acidity, and this guide shows those disagreements instead of hiding them.
Quick answer
- Choose a site in full sun or partial shade, with soil that drains well and stays moist.
- Plant in winter or spring, since the UF/IFAS sheet says trees often transplant best then rather than in the fall.
- Dig the hole about three times the width of the root ball, and do not bring in imported soil to fill it.
- Mulch 3 to 4 inches deep, keep the mulch off the trunk, and prune only lightly.
Know which magnolia you are growing
The UF/IFAS document describes southern magnolia as “a striking garden specimen” that can also serve as a dense screen, a windbreak, or a street tree with the lower limbs removed. It lists USDA hardiness zones as “7A through 10A”, so colder yards fall outside its listed range. Anyone in a colder zone should check that the species and cultivar fit the climate before buying.
The UF/IFAS sheet also notes that the cones ripen in fall and winter to reveal bright red seeds that are “used by a variety of wildlife”, so the tree has a role for wildlife as well as a showy one.
Cultivar names differ in habit and leaf. The Hawaii extension sheet, dated June 1997, describes Cairo as having “very glossy, flexible leaves” and blooming early over a long period. The sheet is older than the UF/IFAS revision of December 2018, so check the current listing for cultivar details before you plant.
The sources do not cover every magnolia. The University of Washington page is about new magnolia trees in general, but the two extension documents are about southern magnolia. Most of the advice below therefore applies to that species, and a reader growing a different magnolia should confirm the details first.
Pick a site with sun, shelter and drainage
The UF/IFAS sheet gives the light range as “full sun to partial shade”. It adds that if moist, peaty soils are available, the tree “will thrive in full sun and hot conditions once established.” In the same sheet, the soil statement is looser: southern magnolia “prefers acid soil but will tolerate a slightly basic, even wet or clay soil.” That is a wider range than the Hawaii sheet, which asks for soil that is “fertile, acidic, well drained, and high in organic matter.”
The two statements disagree on soil pH. The Hawaii sheet names acidic soil as its target, while the UF/IFAS sheet says the tree tolerates slightly basic and even clay soil. A soil test before planting will show which condition applies to your yard. For a kit, see our guide to soil testers for garden beds.
The Hawaii sheet says the tree will “tolerate some shade”, and the UF/IFAS sheet adds a watering point: if irrigation cannot be provided on a regular basis, plants placed in partial shade for several years after planting seem to grow better. None of the three pages gives a wind or exposure rule, so this guide does not add one.
Plant in winter or spring, not the fall
The UF/IFAS sheet is direct about timing. It says “trees often transplant best in winter and spring, not in the fall.” It also explains why: field-grown trees have a wide-spreading root system from the nursery, and they recover slowly from transplanting. The Hawaii sheet agrees that transplanting is hard on large trees: “Large plants are difficult to transplant.”
The University of Washington page focuses on the hole and the roots. It says “dig the hole three times the width of the root ball and place the dug out soil back in the hole with no other soil additives.” It also says “you do not need to amend the hole with new or superior soil from another source” as the current consensus, and it gives the reason: the roots need to grow outward into the native soil for the tree to become established.
Planting depth also matters. The UW page names planting “too low in the ground” as the risk to guard against, but its depth warning is tied to grafted trees, so check how your tree is grafted before you set it. Whatever the tree, check the top of the root ball against the ground before you backfill.
Mulch carefully and water through the first seasons
Mulch is where the UW page is most specific. It recommends a mulch ring that starts about 6 inches from the trunk and reaches the outer edge of the root ball, so the mulch does not touch the bark. It warns against piling mulch against the trunk, because that “can cause rot.” In winter the page says “3-4 inches of mulch is plenty”, because a deeper layer can keep water out of the soil.
The Hawaii sheet gives a flat rule that matches: “Apply a 3-inch layer of mulch to help hold moisture and reduce soil temperature.” Together the two pages put the depth at three to four inches, with the mulch kept clear of the trunk and not too deep in winter.
The UW page adds that mulch matters most from spring through fall, “for keeping water from evaporating from the soil surface”, and that it also helps slow the weeds.
Watering is less specific. The UF/IFAS sheet says to keep trees healthy by watering in dry weather, and it links regular fertilization to health. None of the three pages gives a watering frequency or a number of days between waterings for a new magnolia, so this guide does not give one. Check the soil in the root zone before each watering, and let the mulch do its share of the work of holding moisture.
Prune lightly and let the form develop
The Hawaii sheet gives the clearest pruning rule: “Train young trees to promote desired growth habit and then prune only lightly to maintain desired shape.” The UF/IFAS sheet puts it more briefly, listing the pruning requirement as “little required”. That is consistent with the UF/IFAS note that little pruning is required.
Some growers want a trained form. The UF/IFAS sheet notes that, with proper pruning, southern magnolia can be trained as an espalier, and it also names dense cultivars for use as a hedge or screen. The pages do not give a pruning month, so this guide does not give one.
For the tools that suit light pruning, see our guide to pruning saws for larger limbs and the tips on pruners for trees.
Feed with a light hand, if at all
The Hawaii sheet ties growth to care: “with proper soil preparation and fertilization”, the growth rate is moderate to fast. The UF/IFAS sheet also recommends regular fertilization to keep trees healthy. Neither page gives a rate, a product or a schedule that this guide could quote.
A UGA publication on southern magnolia came up in search, but it returned HTTP 403 when opened, so it is not used here. A feeding plan should follow a soil test and the rate on a current extension publication, not a number from an older sheet.
Seasonal timing at a glance
| Season | What the sources support |
|---|---|
| Winter | Best transplant window for the UF/IFAS sheet; mulch should not be too deep in winter, per the UW page. |
| Spring | Second transplant window for the UF/IFAS sheet; mulch is kept through the growing season. |
| Summer | Mulch helps keep water from evaporating from the soil surface, per the UW page. |
| Fall | Not the preferred transplant time, per the UF/IFAS sheet. |
The table has no row for pruning or watering, because none of the three pages gives a month or a frequency for either.
Problems and conflicts in the sources
The biggest disagreement is soil pH. The Hawaii sheet asks for acidic soil, and the UF/IFAS sheet says the tree will tolerate a slightly basic or clay soil. Both statements come from sources that are careful about their scope, so the honest answer is to test the soil and plan for the range that matches the result.
The second difference is age. The Hawaii sheet is dated June 1997, while the UF/IFAS sheet was revised in December 2018. Where the two disagree, the newer sheet is the better guide, but the older one still contributes its pruning and mulch rules.
The UW page is a library answer rather than an extension publication. It reports advice from a Washington State University Extension professor, and this guide cites the page rather than the professor. The mulch depth it gives is consistent with the Hawaii sheet, so the two do not conflict on that point.
Mistakes to avoid
- Planting in the fall, when the UF/IFAS sheet says trees transplant less well.
- Filling the hole with imported soil, which the UW page says is not needed.
- Piling mulch against the trunk, which the UW page warns can cause rot.
- Laying mulch too deep in winter, which the UW page says can keep water out of the soil.
- Pruning heavily, when the Hawaii sheet says to prune only lightly.
- Relying on the 1997 Hawaii sheet for cultivar details instead of current listings.
How we chose
We limited the guide to three pages that returned HTTP 200 when opened with curl on 2026-10-23 and that contain planting or care text. One is a Kentucky state copy of a UF/IFAS southern magnolia fact sheet, one is a University of Washington Libraries answer on new magnolia trees, and one is a University of Hawaii Cooperative Extension sheet. Several other magnolia pages returned 403, redirected to a homepage, or redirected to an error page, so they are not used. No retail listing supplied any care fact, and each quotation was checked against the text of the page it comes from.
What we could not verify
The sources we opened cover southern magnolia in most detail, and they do not cover the other magnolias that gardeners often plant. The UF/IFAS sheet and the Hawaii sheet cover a warm-climate species, so their timing and hardiness notes may not fit a colder yard. Two of the three pages are older or general in scope, and the most detailed extension feeding publication did not open.
What the sources do not say
None of the three pages gives a watering frequency, a fertilizer rate, a pruning month, or a hole depth in inches. They do not name the best cultivar for a given yard, and they do not give a size at maturity that this guide can quote. This guide leaves those points open rather than filling them with general habits.
Frequently asked questions
Can a magnolia tree grow in partial shade?
Yes, according to the UF/IFAS sheet, which gives the light range as full sun to partial shade. It also says that a tree placed in partial shade for several years after planting seems to grow better when irrigation cannot be provided regularly.
When is the best time to plant a magnolia tree?
The UF/IFAS sheet says trees often transplant best in winter and spring, not in the fall. The University of Washington page does not name a season, so the UF/IFAS timing is the one this guide follows.
How deep should the mulch be around a magnolia?
The UW page says three to four inches is enough in winter and warns against mulch so deep that it keeps water out. The Hawaii sheet gives a three-inch layer. Both pages say to keep the mulch off the trunk.
Should you add compost to the planting hole?
The UW page says the current consensus is that you do not need to amend the hole with new or superior soil from another source. Neither extension sheet addresses amending the planting hole, so the UW page is the only source on this point.
How much should you prune a young magnolia?
Prune only lightly, according to the Hawaii sheet, which asks for training of young trees to promote a good growth habit. The UF/IFAS sheet lists the pruning requirement as little required, and it notes that proper pruning allows a trained form.
Sources
- https://eec.ky.gov/Natural-Resources/Forestry/ky-champion-trees/Documents/Southern%20Magnolia%20Fact%20Sheet-IFAS%20Extension.pdf (opened 2026-10-23)
- https://depts.washington.edu/hortlib/pal/planting-and-caring-for-new-magnolia-trees/ (opened 2026-10-23)
- https://www3.ctahr.hawaii.edu/oc/freepubs/pdf/OF-9.pdf (opened 2026-10-23)
