The sun plays an important role in the growth of hydrangeas. Too much sunlight can cause serious problems, just as a lack of light can negatively affect these plants. In fact, this is an important question that arises in many gardeners.
Hydrangeas need at least 4-6 hours of direct sunlight. Some species need a little more, some less. There are species of hydrangea that can generally grow in full shade, but it depends on the climate in which it grows.
To determine which hardiness zone you live in, look at this map.
|Mophead hydrangeas||4-6 hours|
|Mountain hydrangeas||5-8 hours|
|Panicle hydrangeas||6-10 hours|
|Smooth hydrangeas||5-8 hours|
|Oakleaf hydrangeas||3-6 hours|
|Climbing hydrangeas||4-6 hours|
Hydrangea macrophylla does not need much sunlight, and part of the day prefers to be in the shade. However, they still need direct sunlight for at least 3-4 hours a day.
Most varieties feel good in Hardiness zones 5-9. In different areas, the amount of light that should receive Bigleaf hydrangea will be different.
In 5-6 zones, plants of this species need more sun because there it shines less. So if you live in Vermont, Massachusetts, New York (north), West Virginia, etc., plant Mophead hydrangea so that it is exposed to about 6 hours of direct sunlight per day. This amount of light is enough for normal growth and flowering.
The further south you need less sun. The excess sun can cause some problems so in hardiness zones 7-8 (New Mexico, Georgia, Maryland, Massachusetts, North Carolina, Tennessee, Texas, etc.) Hydrangea macrophylla should take 4 hours of sunshine or even less.
It is best if it is the morning sun because the angle of the sun’s rays will not be 90 degrees, and therefore the conditions will be milder.
The most common varieties of Hydrangea macrophylla include:
- Soeur Therese
- Blue Lace;
- Merveille Sanguine
- Hot Red
The recommendations above are perfect for them. However, there are varieties that can tolerate other weather conditions, so let’s take a quick look at them.
Some varieties can be grown in hardiness zone 9 (Texas, Nevada, Louisiana). These include:
- Lanarth White
- Early Blue
- Big Daddy
In such a hot climate, they should not get much sun, 2 hours will be enough for them.
On the other hand, such varieties as Endless Summer, Summer Crush, Bloomstruck tolerate the harsh conditions of hardiness zone 4. In such a climate, they will need more light, seven or even eight hours of direct sunlight will be just right.
Hydrangea Serrata is hardier and can take in more sun so the leaves will be brighter, and the flowers will be more.
This type of hydrangea can grow in hardiness zones from 5 to 9. It is less resistant to low temperatures than the previous one.
In colder climates, hardiness zones 5-6 (Colorado, Michigan, Indiana, Connecticut, Missouri) Mountain hydrangeas can be planted in a place where it will be exposed to direct sunlight for more than 6 hours a day.
There is information about the successful cultivation of this species in a place with 8-9 hours of direct sunlight, although in this case, you need to increase watering.
In warmer states of hardiness zone 8-9 (Oregon, Nevada, Washington), these plants can withstand a little more than 4 hours of direct sunlight. Although it is not worth to exceed this mark, 5-6 hours is enough.
As in the previous case, these plants should receive at least 4 hours of direct sunlight daily, regardless of the climate in which you live.
The most popular varieties of Mountain hydrangea:
- Tuff Stuff
- Tuff Stuff Ah-Ha
- Tiny Tuff Stuff
- Blue Deckle
- Blue Billow
All of them can be grown without any problems in compliance with the above recommendations.
Hydrangea paniculata is the best of all hydrangeas able to tolerate the sun. The lower threshold of sunlight is 4-6 hours a day.
Another advantage of this species is that some varieties can tolerate very low temperatures (-35 ° F). Panicle hydrangeas can be successfully grown in hardiness zones 3-8.
In states closer to the north (hardiness zones 3-5), these hydrangeas need more than 4 hours of sunshine to grow better. You can plant them in an open area so that they receive 8-10 hours of direct sunlight and do not have to increase watering.
In the north of the states adjacent to the border with Canada (hardiness zones 3), this hydrangea can be planted in a place with 12 hours of direct sunlight. However, it is worth doing if you are an experienced gardener and know your plants well.
In warmer states that are in hardiness zones 6-8 (Alabama, Kansas, Utah, Pennsylvania, and others), the amount of light will have to be reduced. Put Hydrangea paniculata in place so that it receives up to 8 hours of direct morning sun (from 6 AM to 12 AM).
The most common varieties that can get a lot of sunlight:
- Fire Light
- Little Quick Fire
- Diamond Rouge
- Pink Diamond
- Quick Fire
Hydrangea arborescens can grow from hardiness zone 3 to 9. It also tolerates the sun well. She needs at least 4 hours of direct sunlight daily.
In hardiness zone 3-5, it needs at least 6 hours of direct sunlight, but it is better if it is 8-9 hours.
In hardiness zone 7-9 (Florida, Arizona, California), you need to plant varieties of this species in partial shade. More than 6 hours of sun will be too much, 4-5 hours is just enough. It is best for the plants to receive the sun from 6 AM to 10 AM, then they need shade for the rest of the day and into the evening.
Most common varieties:
- Invincibelle Wee White
- Invincibelle Ruby
- Invincibelle Mini Mauvette
- Haas Halo
Like most hydrangeas, Hydrangea quercifolia prefers the morning sun and the rest of the day shade. One thing that distinguishes it from other species is that it tolerates full shade better.
This species can grow from 5 to 9 Hardiness zones.
In 5-6 zones, plants of this species need at least 4-5 hours of direct sunlight.
In zones 7-8, you need to put them in place with 3-4 hours of sunshine. And only in the 9 hardiness zone, Oakleaf hydrangea can grow in full shade. However, you need to look after the plant and transplant it if there is a lack of light.
The most popular varieties of this species:
- Ruby Slippers
- Snow Queen
- Pee Wee
- Gatsby Moon
- Ellen Huff
- Climbing hydrangeas
Hydrangea petiolaris has about the same sun requirements as most hydrangeas.
In colder climates, it needs about 6 hours of direct sun (zones 4-5). In warmer states (zone 7) this plant will have enough 4 hours of sun.
- Hydrangea anomala subsp. petiolaris
- Climbing Hydrangea Vines
- Hydrangea anomala subsp. petiolaris ‘Flying Saucer’
- Hydrangea anomala subsp. glabra ‘Crûg Coral’
Too much sun
If you plant a hydrangea in a place where there is too much sun, then some problems may arise.
First of all, in dry and hot weather, the plant can wither. Mostly it happens in the evening; if during the day it was hot, then in the evening the petioles will lean down, the leaves will also become soft.
In this case, you should water the plant as soon as possible. In the future, you will have to water more often.
Sometimes it happens that the soil around is moist, but the hydrangea still withers. If this happened to your plant, then do not worry too much, it will draw water during the night, and in the morning everything will be fine. In this case, you do not need to water the plant additionally, because it can cause root or crown rot.
The second symptom of excess light may be leaf scorch. From the strong sun and lack of moisture, the leaves begin to dry at the edges and scorch. In this case, you need to increase watering.
Also, with plenty of sunlight, hydrangea leaves can get burns. It will look like big yellow spots on green leaves. Sometimes the leaves can turn yellow more than half or completely. Additional watering will not help here.
To avoid further burns, you should shade the plant. You can do this in two ways:
- Tighten the shading net in front of the plant;
- Plant a larger plant in front of the hydrangea.
However, the best solution is to transplant the hydrangea to a more suitable location. The best solution is to plant it on the east side of the house. In this case, the plant will receive light only in the morning.
If you live in a hot climate (8-9 hardiness zones), then you better prefer the varieties of Hydrangea paniculata.
Not enough sun
Insufficient sunlight can also cause problems with hydrangeas.
The first consequence of a small amount of light will be the lack of flowering. Flowers are the reason for the high popularity of hydrangeas. Therefore, for beautiful flowering requires direct sunlight (at least 3-4 hours).
The second thing that can happen if you plant a hydrangea in full shade is that the stems will be very brittle. In the absence of light, they will not mature normally, and strong winds will break.
In a shady place, when there are prolonged rains, hydrangeas will get sick more often. In such conditions, fungal diseases will develop, especially quickly. As a result, you will have to spray the plants more often with fungicides.
To avoid all the above consequences, you need to plant a hydrangea in a place where it will receive direct sunlight for at least 3-4 hours.
If you do not have enough sunny places, then you should prefer Oakleaf hydrangeas. In the southern states, they can grow without direct sunlight.