Flowering plants require a lot of light to bloom abundantly. This is because flowering and seed ripening requires a lot of energy.
Magnolia plants need at least 6 hours of direct sunlight per day. It can also tolerate a lot more sunshine hours per day. In this case, you can get a large number of flowers and vigorous growth.
This is the short answer to the lighting requirements of the magnolia and will be explained in more detail later. By the way, I have an excellent article on How To Grow Magnolias which I strongly recommend you to read.
Magnolias need at least six hours of direct sun per day for good flowering. The further north you go, the more sun it will need. For example, in 4 and 5 USDA hardiness zones, the sun exposure should be increased to 8 hours.
At the same time, a magnolia tree can tolerate full sun all day. That means you can plant it on the south side of the house and it will be comfortable.
The only exception to this rule is the states that are in the 9-10 zone. In those climates, some magnolias still need protection from the mid-day scorching sun.
The best sun exposure is morning direct sun before noon. Then the magnolia can stay in the shade receiving only reflected sunlight.
Also, be sure to ask your magnolia supplier about how many hours of light your chosen variety needs. This is because there are many different varieties that have slightly different sun requirements.
Too much sun
There are cases where magnolia trees can suffer from excessive sun exposure. The first of these is newly planted magnolias.
In the first year of life in a new location, the magnolia is just beginning to establish a root system. It often happens that by mid-summer, the root system is not yet developed and is not able to deliver enough water to the leaves.
As a result, the leaves may turn yellow or droop under the summer sun. Also, sometimes the leaf margin can get burnt.
Planting or transplanting magnolia in late spring or early summer makes this problem even worse. Also, damage to the root system can reduce the magnolia’s resistance to the sun.
To avoid sun damage:
- Plant or move magnolia exclusively in early spring or late winter. When doing this, be as gentle with the roots as possible.
- During the first growing season, shade the magnolia for the summer months. You can do this by using a garden umbrella.
- Check the moisture content of the soil regularly and once it is 1-2 inches dry, water the magnolia with a gallon of water or a little more.
- Be sure to mulch it with organic mulch in a 2-3 inch layer avoiding volcano mulching.
As I mentioned earlier in the southern United States, not all magnolias can tolerate planting in full sun all day equally well. So you need to find out exactly how much sun a particular magnolia variety can tolerate and place it accordingly.
Full shade is where you don’t want to plant your magnolia in any way. In nature, these trees grow to a considerable size and are never placed in full shade.
To get abundant blooms and a beautiful crown, you have to mimic the natural conditions.
If there is a lack of light, the magnolia can bloom very poorly or not at all. Also, its crown will be loose and less branched. Diseases and pests will affect such a tree much more often.
By lack of light, I do not only mean total shade but also insufficient sunlight hours. For example, if a magnolia gets 4 hours of light or less, this can be a problem.
If your magnolia is growing in full shade, you need to transplant it to a location with at least 6 hours of direct sunlight. Do this in early spring and don’t hurt the roots.
If the magnolia gets direct sun but not enough, then fertilize it with a slow-release multi-purpose granular fertilizer. This can partially make up for the lack of sunlight.
As for potted magnolias, their relationship to the sun is a little different. You should not place them in full sun.
This is because the pot can get very hot and the soil will dry out quickly. The magnolia can suffer a lot as a result.
It is better to place the container in the semi-shade, for example, on the east side of the house. Four to eight hours of direct sunlight per day is optimal.
Also, make sure that the pot is placed on the ground and not on concrete or tile. It is important that it does not overheat. If possible, protect the container from direct sunlight.