10 Tips For Growing Magnolias In Containers

There are so many stunning trees that make a statement in a garden, but my favorite has to be the magnolia. There is something about the glossy leaves and massive scented flowers that makes an impression unlike any other tree.

Unfortunately, magnolia trees are also (usually) massive. With some species reaching up to 80 feet in height, those with limited backyard space or no backyard space at all may have crossed magnolias off their list altogether.

Well, I’m here to tell you you don’t need to. It’s not only possible to grow magnolias in containers, but it’s easy, too. My two potted magnolias are my favorite garden purchases (don’t tell the rest of my plants), and these are the ten tips I’ve learned for success along the way.

Choose The Right Variety

There are many magnolia species and even more cultivars to choose from, but not all are suitable for growing in containers. In fact, most aren’t ideal, reaching heights up to 80 feet and needing plenty of space to expand.

To grow magnolias in containers successfully long-term, you need to choose a smaller variety that can handle the confined conditions of a pot. Luckily, there are a few stunning dwarf varieties that are perfect for containers.

‘Little Gem’ is one of the most popular cultivars of Magnolia grandiflora for smaller gardens or growing in pots. My local nursery has a few on display at the front entrance in large grow bags, and they are thriving, even with the limited root space.

After size, climate is also vital to consider. This cultivar is hardy down to USDA Zone 7, but if you live in a colder region, you can try other small magnolias like Magnolia stellata ‘Centennial Blush’ that grows best in USDA Zones 4-8.

These are a few of the other dwarf cultivars at or below 20 feet in height, suitable for pots:

• Magnolia liliiflora ‘Nigra’
• Magnolia laevifolia ‘Gail’s Favorite’
• Magnolia stellata ‘King Rose Star’
• Magnolia x soulangeana ‘Alexandrina’
• Magnolia ‘Petit Chicon’

Choose The Right Container

Next, you’ll need to choose a container. If you’re planning on transplanting your tree later on, a pot just slightly larger than the bag is manageable. But if you want your magnolias to live in pots forever, the larger the container, the better.

Even small magnolia trees have expansive root systems that need room to support the branches and leaves above. Your long-term container should be several sizes larger than the current pot or bag the tree is in, both in depth and in width.

The other non-negotiable is drainage. The container needs to have drainage holes in the bottom to allow excess moisture to escape, preventing root damage. Ideally, choose a pot made from porous materials that will help wick moisture away from the roots, too.

Larger containers can be pricey, especially if you’re choosing a porous material like terra cotta. However, investing in a larger container is better than restricting the tree early on, leading to growth problems down the line.

Place Your Container Before You Plant

Large containers are heavy. Tall magnolia trees are also heavy. Combine those two, adding in a few bags of moist potting soil, and your pot will become almost impossible to move on your own.

You can use a trolley to wheel heavy pots around, but I find it far easier to choose your location before you plant.

The most important considerations are environmental – sunlight, potential for frost, wind protection, and so on. If you have a few suitable spots, your choice will come down to aesthetics. And in these cases, it can be tough to decide on the right location until you see it.

When I was potting up my magnolia trees, I knew I wanted them near my patio. But the exact location on the patio was still undecided. With a little help, I moved the pots to a few locations and lowered the trees inside to get a feel for what they would look like. Once I found the perfect spot for visual balance, I left the containers there and prepped for planting.

Use Pot Feet

This next tip applies to all your containers but is especially helpful for larger trees that won’t be moved after planting.

Placing pot feet at the bottom of the container lifts the pot slightly off the ground, preventing any moisture from becoming trapped around the base or damaging the surface the container is placed on. This isn’t as important if the container is placed on soil or grass, but can protect your balcony or patio from the damage that comes with long-term watering.

You can purchase pot feet to match your chosen container, placed around the rim of the pot to lift it and improve drainage. You can also use things you may already have around your garden, like bricks, to raise the pots, as long as they are sturdy, can withstand the weight of the container, and don’t block the drainage holes.

Amend Soil With Compost

Magnolias love rich, slightly acidic soil that retains enough moisture to keep the roots happy but also drains well to prevent rot.

High-quality potting soil is usually sufficient, containing organic matter and often some additional nutrients too. But if you want to give your trees the best possible start, add some extra compost into the mixture before planting.

Whether your compost is homemade or bought from a nursery, it contains beneficial nutrients and microorganisms that improve root growth. Compost also retains moisture and has a slightly acidic pH, creating the soil conditions these trees love.

When potting up my trees, I used five bags of potting soil and three bags of compost. Mix the soil well before planting, as mixing evenly inside the containers is tough.

Place In Full Sun To Partial Shade

To ensure your magnolia flowers grow prolifically in containers, you need the right amount of sunlight. Too little sun will stunt growth, leaving the plant without enough energy to grow properly or flower at the right time.

Most magnolias grow best in full sun positions, but some can also grow in partial shade. If you live in a warmer climate, partial shade is recommended, as intense afternoon sun can scorch the leaves.

Also, consider the conditions the tree was in when you bought it to understand the environment it has adapted to. My magnolias were growing largely in dappled sunlight at the nursery and struggled when I moved them to direct sun in my garden. They are slowly adapting now, but there were plenty of scorched and curled leaves in the process.

Keep an eye out for signs of struggle, like scorching or lack of new growth, that signal you may need to move your container to a new position.

Water Regularly

Magnolia trees planted in the ground don’t require much additional watering once established. They usually survive on rainfall alone, with a little extra help during warm and dry periods. Conditions for magnolias in containers are slightly different, requiring closer attention to moisture levels.

When you first plant your magnolia trees, it’s best to water them 2-3 times per week. This encourages the roots to spread out in the pot and helps the tree establish. Once the tree has settled, you can adjust your watering routine to around once per week, depending on weather conditions.

The soil in containers dries out much quicker than soil in the ground. If you forget to water, the soil will quickly become dry and compacted, stressing your tree. Aim for a regular watering schedule that adds moisture just as the soil starts to dry out again.

Use Mulch

One of the ways to retain moisture in containers is by adding a layer of mulch.

Mulch traps moisture in the soil by slowing evaporation and regulating soil temperature, protecting the roots. This also protects the shallow roots close to the soil line from sunlight damage, especially at the height of summer.

Choose an organic mulch that will slowly break down over time, adding nutrients back into the soil. I like to use a thick layer of compost, but bark or straw is also suitable. You can also add a sun-loving living mulch like sweet alyssum for aesthetic value, although it won’t retain moisture as well as the other options.

Don’t Forget To Fertilize

Nutrients in the soil in containers deplete over time as the plant uses them for growth. Without regular top-ups, the soil eventually won’t have enough nutrients to support new root, branch, and leaf growth or – most importantly – flowers.

You don’t need to fertilize immediately after planting if you’ve chosen potting soil packed with nutrients. It’s best to give the roots time to settle in first. But once your tree is established, regular feeding is vital if you want your magnolia to continue to grow and flower.

I like to mix a slow-release fertilizer into the top layer of soil once in spring and again in fall. These fertilizers break down over time, releasing nutrients as you water. You don’t need to add a lot – just enough to replenish any nutrients that may have been lost.

In summer, you can also supplement with a low-strength liquid fertilizer around once per month as needed. Excess fertilizer can lead to root damage, so it’s important not to overdo it. Monitor growth closely and never apply more fertilizer than is recommended on the packaging of your chosen product.

Prune Lightly

Magnolia trees don’t need to be pruned regularly to flower well. In fact, pruning too much can cause more harm than good, potentially halting flowering across the next season.

You can prune your magnolias to shape the tree, remove crossing or damaged branches, and manage its size for the container as it matures. But whenever you do prune, don’t trim too much. Only cut back what is needed, keeping as much growth on the tree as possible. This will give you the best chance of flowering the following season.

The best time to prune is just after the tree has finished flowering, which will differ slightly depending on species and climate. Cut back as needed with sharp and clean shears to prevent the spread of disease. If you’re happy with the size and there are no areas of damage or disease, you don’t have to prune.