All plants need sunlight to grow. For hydrangeas, too much sunlight or too little sunlight can both cause problems.
Hydrangeas need 4 to 6 hours of daily sunlight on average. This varies on the specific Hydrangea as some can grow in less sunlight, while some need more. Some Hydrangea species can also grow in full shade.
Let us have a detailed look at the sunlight needs of specific Hydrangeas.
How much Sunlight do Mophead hydrangeas need?
Mophead hydrangeas (Hydrangea Macrophylla), do not need a lot of sunlight. They need direct sunlight for at least 3 to 4 hours a day and need shade for a part of the day.
Most varieties of mophead hydrangeas can grow well in hardiness zones 5 to 9. However, in different zones, the amount of light required by the plants will be different.
In zones 5 to 6, the climate is cold so the sun shines less intensely. That is why, in these regions, the hydrangea requires more sunlight.
Plant your hydrangea in a location where it will get at least 6 hours of direct sunlight daily. This light will be enough for the plant to grow and flower properly.
In hardiness zones 7 to 8, it is already hot, so the hydrangea will need less sun. excess sun can also cause problems.
In these regions, Hydrangea Macrophylla would only need up to 4 hours of sunlight every day, or maybe even less. The morning sunlight is the best, as the sun’s rays are at an angle, making the heat mild.
Common varieties of hydrangea Macrophylla
- Soeur Therese
- Blue Lace;
- Merveille Sanguine
- Hot Red
These varieties can be taken care of by following the information given above.
However, there are also some other varieties of Hydrangea Macrophylla that can grow in other conditions.
Varieties of mophead hydrangeas that can be grown even in hardiness zone 9
- Lanarth White
- Early Blue
- Big Daddy
This zone has a very hot climate. The plants should not get a lot of sun in this climate. 2 hours of direct sunlight every day can be enough.
Mophead Hydrangeas that can tolerate the weather conditions in hardiness zone 4
- Endless Summer
- Summer Crush Hydrangea
In this cold climate, these plants will need more light. 7 to 8 hours of direct sunlight daily will be ideal for the varieties growing in this climate.
Sunlight Requirement for Mountain Hydrangeas
Mountain hydrangeas (Hydrangea Serrata) is a hardy plant. This plant can tolerate more sunlight; thus, the leaves of this variety are more saturated and the number of flowers is more.
Mountain hydrangeas grow in hardiness zones 5 to 9. It is not quite resistant to cold temperatures.
If you plan to plant mountain hydrangeas in an area with a very cold climate, in zones 5 or 6, you need to plant them in a place where they will receive more than 6 hours of direct sunlight every day.
Mountain hydrangeas have also been known to grow in areas that get 8 to 9 hours of direct sunlight. However, in this case, the plant needs to be watered more often.
In hardiness zones 8 to 9, where the climate is quite warm, this variety can grow with more than 4 hours of direct sunlight per day, although 5 to 6 hours of sunlight is sufficient for the plant.
In any case, hydrangea Serrata should receive at least 4 hours of direct sunlight every day no matter the climate in your region.
Varieties of mountain hydrangeas:
- Tuff Stuff
- Tuff Stuff Ah-Ha
- Tiny Tuff Stuff
- Blue Deckle
- Blue Billow
Sunlight Requirement for Panicle hydrangeas
Panicle hydrangeas (Hydrangea paniculate) is the best variety of hydrangeas to withstand heat. This variety of plants needs a minimum of 4 to 6 hours of sunlight a day.
Some varieties of panicle hydrangeas can grow in very low temperatures as well, up to (-35 ° F). you can grow panicle hydrangeas in hardiness zones 3 to 8.
If you live in a place of hardiness zone 3 to 5, these hydrangeas will need more than 4 hours of direct sunlight every day to grow well.
You can even plant them outside where they will get up to 8 to 10 hours of direct sunlight. Because of the cold, you do not have to increase the frequency of watering either.
In regions in hardiness zone 3 where the climate is very cold, you can plant this variety of hydrangea in a place that gets 12 hours of direct sunlight. However, it is better to do this only if you are experienced in gardening.
On the other hand, in the warmer states that come in hardiness zones 6 to 8, the amount of sunlight your plant receives will have to be reduced.
You can plant your panicle hydrangeas in a place where it receives up to 8 hours of direct early morning sunlight.
Varieties of panicle hydrangeas:
- Fire Light
- Little Quick Fire
- Diamond Rouge
- Pink Diamond
- Quick Fire
Sunlight Requirement for Smooth hydrangeas
Smooth hydrangeas (Hydrangea arborescens) grow in hardiness zones 3 to 9. This variety can also tolerate the sun well. It needs at least 4 hours of direct sunlight every day.
In zones 3 to 5, smooth hydrangeas will need at least 6 hours of direct sunlight, however, it would thrive better with 8 to 9 hours.
In hardiness zones 7 to 9, this variety will need to be planted in an area that is partially shaded. More than 6 hours of direct sunlight in these zones can be harmful to the plants.
4 to 5 hours of sunlight is ideal. Plant the hydrangeas in such a way that they will receive direct morning sunlight and will be shaded for the rest of the day.
Varieties of smooth hydrangeas:
- Invincibelle Wee White
- Invincibelle Ruby
- Haas Halo
- Invincibelle Mini Mauvette
Sunlight Requirement for Oakleaf hydrangeas
Oakleaf hydrangeas (Hydrangea Quercifolia) like most other hydrangeas need morning sunlight and shade for the rest of the day, the only difference is that oakleaf hydrangeas can grow well even in full shade.
Oakleaf hydrangeas grow in hardiness zones 5 to 9.
In zones 5 to 6, these plants require at least 4 to 5 hours of direct sunlight daily. Whereas, in zones 7 to 8, your hydrangeas will need 3 to 4 hours of sunlight.
In hardiness zone 9, oakleaf hydrangeas can grow in full shade. However, you will need to take extra care of the plant and might need to transplant it if there is no exposure to light at all.
Varieties of oakleaf hydrangeas:
- Ruby Slippers
- Snow Queen
- Pee Wee
- Gatsby Moon
- Ellen Huff
Sunlight Requirement for Climbing hydrangeas
Climbing hydrangeas (Hydrangea petiolaris) have similar requirements as most other hydrangeas.
In hardiness zones 4 to 5, where the climate is cold, this variety will need about 6 hours of daily sunlight.
In zone 7, where it is warm, 4 hours of direct sunlight every day will be sufficient.
Varieties of climbing hydrangeas:
- Hydrangea anomala subsp. petiolaris
- Climbing Hydrangea Vines
- Hydrangea anomala subsp. petiolaris ‘Flying Saucer’
- Hydrangea anomala subsp. glabra ‘Crûg Coral’
Effects of too much sunlight
Planting your hydrangea in a place where it is exposed to excess sunlight can cause issues.
Sometimes, in hot and dry weather, the hydrangea can wither. Usually, if it was hot during the day, the plant will wither and droop in the evening and the leaves will also become soft.
In this case, water the plant as soon as possible, and make sure you water more frequently in the future.
It can also happen that you have sufficiently watered the plant and the soil is moist, but the plant still withers. In this case, the plant will absorb the water at night and be normal the next morning.
Do not water the plant if the soil is moist, otherwise, it can cause root rot or crown rot.
Another effect of too much sunlight can be leaf scorch. If your hydrangea is exposed to intense sunlight for a long time and comparatively less moisture, the leaves will begin to dry around the edges.
You need to increase the frequency of watering if this is the case.
Your leaf will eventually also start getting burnt. At first, they will be yellow spots on the green leaves that will grow bigger. The leaves can also become completely yellow.
If the plant is already burnt, more water might not be the solution.
You can try to shade your plant in this case. You can tighten the shading net in front of the plant, or you can plant a larger plant near the hydrangea so that it gets natural shade.
An even better option will be to transplant your hydrangea in a location where it is shaded from harsh sunlight for most of the day.
A good location would be to plant your hydrangea to the east of your house so that it will get access only to the morning sunlight and will remain shaded for the rest of the day.
If you live in a hot region, you might prefer the hydrangea paniculate varieties, as they can tolerate sunlight very well.
Effects of not enough sunlight
Just like with excess sunlight, not getting enough sunlight can also cause problems for hydrangeas.
Lack of flowering
Plants need sunlight for the energy required o grow flowers. Lesser sunlight will mean a lesser number of flowers or smaller blooms.
Hydrangea is known for its large and beautiful flowers. The plant requires at least 3 to 4 hours of direct sunlight every day for large and beautiful flowers.
Read more about reasons for Hydrangea not flowering here – https://growveggy.com/b/hydrangea-not-flowering/
If you plant your hydrangea in a place where it has no access to any light, the stems of the plant will grow brittle.
Plants need sunlight to grow, and without any light, the plants will not mature as they normally would and grow weak.
If your hydrangea is planted in a shaded place where it gets a lot of rain, it will be very prone to getting sick regularly. These are not good conditions for hydrangeas to grow.
It can cause fungal diseases to develop at a fast rate. So, you will need to constantly spray the plant with fungicides.
Make sure you plant your hydrangeas in a location that receives at least 3 to 4 hours of direct sunlight every day.
If you cannot find a sunny enough place, you can think about growing oakleaf hydrangeas. This variety can grow even without direct sunlight.