Dahlias prefer growing under full sun conditions, these plants are native to Mexico where they grow in full sun locations in well draining sandy soils. With that being said you can grow Dahlias in partial shade as well, and even indoors as long as the Dahlias still get exposed to some direct sunlight.
Dahlias thrive in full sun conditions, ideally in environments with temperatures below 100°F ( 37°C ). However, in areas with hotter temperatures, providing them with partial shade is necessary. It is recommended to offer some shade during the hottest part of the afternoon to protect the dahlias from excessive heat. This helps prevent sunburn and ensures that the plants can thrive and maintain their optimal health.
If you are growing your Dahlias in partial shade then my personal recommendation is to stake them with half round metal stakes Click here to check it out on Amazon.com
The definition of full sun is an area that gets 6 or more hours of direct sunlight per day, partial shade is generally defined as an area that gets more than 4 hours but less than 6 hours of direct sunlight per day. Full shade doesn’t really mean that the area doesn’t get any sunlight, it means that the area gets less than 4 hours of sunlight per day. Dense shade is an area that doesn’t get any direct sunlight at all.
I had to include the definitions of the different light levels as way too many people think that partial shade simply means that the area doesn’t get any direct sunlight. Even partial shade can be separated into 3 categories depending on when they get full sun, and these will determine how you will actually grow your Dahlias in partial shade. If the Dahlia leaves are drooping it could be a sign that they are struggling in partial shade, for more information check out my recent article Dahlia Leaves Drooping ( Top 7 Reasons ).
Growing Dahlias In Partial Shade
Dahlias are typically known for their love of sunshine, but they can still thrive in partial shade conditions. When growing dahlias in partial shade, it’s important to choose the right variety that is known to tolerate or even prefer less sunlight. Look for dahlia cultivars that are specifically labeled as suitable for partial shade. While these plants may produce fewer blooms compared to those grown in full sun, they can still offer beautiful flowers and foliage. When planting in partial shade, ensure that the area receives at least 4-6 hours of direct sunlight each day. Adequate spacing between plants is also important to allow for better air circulation and light penetration.
Partial Shade With Morning Sun
Usually, plants that are categorized as partial-shade plants, will grow the best if they get full sun during the morning. However, morning sun is not the best for Dahlias, they will grow and will even flower but there will be some consequences of growing them in such an area. The main problem with morning sun is that it tends to be extremely weak when compared to the midday sun. As Dahlias do grow the best in full sun conditions, they can struggle if they only get morning sun.
Dahlias that are growing in partial shade with morning sun tend to get leggy and weak, you will see them stretching towards the sun. In this case, it is highly recommended to pinch the Dahlias as soon as possible, do it too late and the stems will be weak and leggy. By pinching the Dahlias you will force them to grow more stems, which will be stronger. The main downside of growing Dahlias in partial shade with morning sun is that they are not guaranteed to flower.
Flowering needs a lot of energy and Dahlias need full sun in order to produce that energy, small Dahlia tubers will have a really hard time flowering. On the other hand, if the Dahlia tuber clump is rather large then the odds of them flowering even in partial shade greatly increase. One of the reasons why Dahlias do not flower is because they don’t get enough sunlight, for more information check out my recent article Dahlias Not Flowering ( Top 7 Reasons ).
Partial Shade With Midday Sun
If you want to grow your Dahlias in partial shade then I would highly recommend you choose a spot that gets midday sun. During midday or noon, the sun is the strongest, and Dahlias will greatly benefit from the increased strength of the sun. As Dahlias would prefer full sun conditions, they will have no problem with growing in the midday sun. In this case, you will find that your Dahlias will not get as leggy as they do in partial shade areas that only get morning sun.
Areas with partial shade and midday sun are the second best to full sun areas. Dahlias growing in these areas will usually have no problem flowering, although I would still recommend pinching them to make them bushier. If you want to know how often you should water your Dahlias then check out my recent article How Often To Water Dahlias? ( Top 9 Things To Consider ).
Partial Shade With Evening Sun
The evening sun is relatively the same strength as the morning sun, so the Dahlias will grow more or less the same. Although Dahlias that only get a couple of hours of evening sun tend to be even leggier than the ones that get morning sun. In this case, I highly recommend both pinching and staking the Dahlias as soon as possible. The leaves might get a slight discoloration to pale green, but if they start to turn yellow or brown then you should really consider replanting them into a full sun location.
Key Takeaways
- Dahlias can be grown in partial shade, although their performance will vary depending on when they get those precious few hours of direct sunlight. Dahlias that are growing in partial shade and with midday sun tend to perform the best, while Dahlias growing in partial shade with morning or evening sun tend to get leggy and are less likely to flower.
- Dahlias in partial shade are not guaranteed to flower, although if they are growing in partial shade with midday sun then the likelihood of them flowering is a lot higher.
- Growing Dahlias in partial shade often makes them get thin, leggy, and weak, even a light breeze can snap the stems so make sure to stake them.