Viburnum is a genus of flowering shrubs – and most species are hardy to Zone 7a (0 Fahrenheit) or colder! Some viburnum varieties can withstand drought, and many are deer-resistant. That still leaves the question of how much sunlight is ideal for this plant.
So, how much sun does viburnum need? Viburnum will grow best in full sun (meaning 6 or more hours of direct sunlight per day). Viburnum does ok in partial shade (2 to 6 hours of direct sunlight), but it needs full sun to produce the best flowers possible. If necessary, prune away overhead tree branches to increase the light your viburnum gets.
Some types of viburnum tolerate cold better than others: at least 20 varieties are hardy to USDA Zone 4a (-30 Fahrenheit). Remember that most viburnum varieties don’t grow well in full shade.
In this article, we’ll talk about how much sun viburnum needs and what happens when light is lacking. We’ll also get into how you can ensure enough light for your viburnum, whether you plant it indoors or outdoors.
Let’s get started.
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How Much Sun Does Viburnum Need? (Viburnum Light Requirements)
Ideally, viburnum needs full sun, which means 6 or more hours of direct sunlight per day (not shade or light filtered through leaves). Direct sunlight can come from morning sun, afternoon sun, or some combination of them.
Some viburnum species tolerate drought, and these specific types can survive in dry, sunny areas where other perennials cannot. So, you can confidently plant viburnum in the sunny parts of your garden that don’t get much shade.
Viburnum does best in a sunny location – full sun will encourage more flowers. However, it can tolerate partial shade if you don’t get enough sunlight in your yard.
Many viburnum species grow poorly in full shade. They will fail to thrive – and most likely, you won’t get the beautiful flowers you are hoping for.
If you already planted viburnum in an area without enough sun, don’t worry – there is still a chance to transplant it later (if it is over 5 feet, you might need a machine). Just remember to do it in early spring or late fall (after leaf drop for deciduous varieties).
Before transplanting, water the soil around the plant if it is dry. When transplanting, try to leave some soil around the roots.
The top of the root ball should be a little bit above the surface of the soil. Also, provide plenty of water after planting, especially for a new viburnum.
Many viburnum species can grow quite tall – some to heights of 10 feet or more! Before they are established, they might have trouble getting enough sun if they are overshadowed by taller plants.
So, plant them in a spot they don’t have to compete with taller plants for sunlight.
Can Viburnum Grow In Full Sun?
Viburnum grows best in full sun – note that “full sun” means 6 or more hours of sunlight per day. Also, remember that viburnum produces more flowers when it gets enough light.
Viburnum flowers vary in color, including golden yellow, cream, tan, green, blue, pink, purple, black, and white.
Many viburnum species tolerate heat, but too much hot sun may cause leaf burn (especially if you transplant from indoors to outdoors). In a sunny, hot climate, consider using a shade cloth to reduce sun’s rays during the afternoon (typically the hottest part of the day).
Will Viburnum Grow In Part Shade?
Viburnum can grow in partial shade (meaning only 2 to 6 hours of sunlight per day). Keep in mind that viburnum tolerates partial shade, but it will not thrive – and its flowers won’t be as stunning as they could be if they had enough light.
If possible, prune away overhanging tree branches to provide more sunlight for your viburnum. Otherwise, try transplanting viburnum to a spot with more sun in early spring or late fall.
Another option is to try to propagate your viburnum. Just make sure the species is not patented (you can ask the nursery or website you buy it from).
You can propagate viburnum by softwood cuttings, hardwood cuttings, or by simple layering.
Can Viburnum Grow In Shade?
Most viburnum species can probably survive in full shade, but they won’t grow as well as they could. They will also produce fewer flowers.
However, there are several viburnum varieties that can tolerate dappled sunlight (living below a canopy of trees):
- Viburnum acerifolium (Maple Leaf Viburnum)
- Viburnum lantanoides (Alder Leaved Viburnum)
- Viburnum lentago (Nannyberry Viburnum)
- Viburnum rafinesqueanum (Downy Arrowwood)
- Viburnum rhytidophyllum (Leatherleaf Viburnum)
- Viburnum suspensum (Sandankwa Viburnum)
If you don’t like the varieties listed above and you don’t have much garden space with partial or full sun, consider skipping viburnum and pick something that tolerates shade. (Speaking of which: you can find 10 great flowering ground cover plants for shady areas in this article).
Why Is My Viburnum Not Blooming?
In many cases, viburnum fails to bloom due to a lack of sunlight. If the flowers are less than they used to be, that could also be an indication that there is not as much light as before.
When deciduous trees produce new leaves, they often overshadow areas that looked sunny in the spring. Also, any trees near a viburnum may have quite a bit (with wider branches) from the prior year, which could also shade your viburnum.
On a sunny day, track the sun in the spot where your viburnum is planted. If it gets shade for most of the day, that is the most probably cause for a lack of flowers.
After you confirm that shade is the problem, one option is to transplant viburnum to a spot with more sun. Another possibility is to propagate by stem cuttings and set the new plant in a brighter spot.
Pruning at the wrong time will also prevent viburnum from flowering. Prune viburnum right after flowering. Otherwise, you will remove flower buds, eliminating the possibility of flowers the next year.
Too much nitrogen might also prevent viburnum from flowering.
Conclusion
Now you know exactly the amount of sunlight viburnum needs (full sun is ideal!) and how to make sure your plant gets enough.
You can learn about the best soil type for viburnum here.
Viburnum has lots of different flower colors, depending on the variety – you can learn more here.
I hope you found this article helpful. If so, please share it with someone who can use the information.
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~Jonathon