How To Grow Potted Willow (And Why Many Salix Are Not Suited To Containers)
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By DAN ORI
Dan has over 27 years’ under his belt caring for plants and gardens. Working as a Horticultural Instructor and Consultant, he draws on a diverse range of experience that includes working as a Head Gardener, Tree Surgeon, Garden Centre Trouble Shooter, and writer of academic papers. Dan has a Level 3 Diploma in Horticulture and is currently a candidate for the RHS’s most prestigious award – The Master of Horticulture.
IN THIS GUIDE
Salix species, which we commonly call willows, sallows or osiers, are a diverse range of beautiful trees and shrubs with varied sizes and forms.
Many can be coppiced or pollarded in order to provide a yield of willow ‘whips’ for a range of uses, whilst some can also be trained to create beautiful fences or other living willow structures.
If you are drawn to the beauty or utility of the salix species but can’t grow them in the soil where you live or have limited space, you might be wondering whether you can grow any of them in pots.
| Difficulty | Hard |
| Equipment Required | Pots or containers, suitable compost mix, water, salix |
Can You Grow Salix In Pots?
The answer is a little more complex than a simple yes or no.
Salix is a genus with around 400 different species, many of which can be grown in UK gardens.1Harris, S. (n.d.-c). Salix species. Oxford University Plants. Retrieved March 27, 2023, from https://herbaria.plants.ox.ac.uk/bol/plants400/Profiles/st/Salix
In general, willows are not necessarily the easiest plants to grow in containers, but that does not mean that there you cannot attempt to grow some salix varieties in this way.
When looking at whether or not we can grow any plant in containers, we need to look at the size to which they will grow, the form of their root systems and their water requirements.
First, let’s take a look at their size.
Salixes can differ extremely in the size to which they will eventually grow.
Some willows will grow into very large standard trees, while others will remain relatively compact or grow with a more shrubby, multi-stemmed form.
Larger willow trees will not be good choices for container growing at all, but some smaller standard trees or extremely compact weeping forms can potentially be grown in containers.
Shrub willows can also be an option for containers, especially when coppiced on a regular basis.
However, even the types that remain compact in form and those that can be regularly cut back hard to keep them contained can be challenging to grow in containers.
The first reason for this is that many willows tend to have extensive root systems that can extend into a large area below the soil.
Constricting their roots can put a strain on these plants and may lead to issues when growing them in containers.
Another reason is that willows often have high water needs.
Even those that are small enough to grow in containers do need to be well watered throughout the growing season and it can be challenging to meet these water needs when they are grown in pots.
This is not to say that it cannot be done with some varieties, but it is important to note that providing the correct care will be essential.
Choosing Willow Varieties For Pots
When choosing a salix for a container, it is important to understand the needs and characteristics of the specific type and variety that you wish to grow.
As mentioned above, many willows are completely unsuited to container cultivation.
Some that can be grown in containers are:
- Kilmarnock willow (S. caprea)
- Flamingo willow (S. integra ‘Hakuro Nishiki’)
- Swiss willow (S. helvetica)
- Woolly willow (S. lanata)
- Willow ‘Boydii’ (S. ‘Boydii’)
“You will normally find that Salix varieties suitable for containers have been top-grafted, which is a cultivation technique where a long single-stem rootstock is cut at a desired height (typically around 1m) and a sion (cutting) is attached,” shares Horticultural Consultant Dan Ori.
“The rootstock will control the vigour of the plant making it achievable to successfully grow a species like Salix caprea in a container.”
Choosing Containers For Salix
When choosing a container for a salix tree or shrub, it is important to select a pot that is as large as possible to accommodate the variety you have chosen.
Make sure that it is heavy and sturdy enough to support a small tree or shrub and that it will not blow over in windy conditions.
Willows typically need free-draining conditions but still require the soil to remain consistently moist through the growing season.
So, make sure that the container does not lose moisture too quickly, but also that excess water can drain away freely at the base.
Potted Willow Compost Requirements
A mix of two parts soil-based compost (John Innes No 3 or equivalent) and one-part peat-free multipurpose compost is ideal when growing salix in containers.
Remember that any mix that you choose must be reasonably free-draining but still retain sufficient moisture.
The mix should also be reasonably rich in organic matter to provide fertility for your salix plant.
Potting Up Salix
Salixes can be purchased as bare-root specimens or as pot-grown plants.
Typically, dwarf varieties are purchased in pots.
As soon as these are purchased and reach your home, you should be sure to pot them up into their long-term containers by following the steps below.
Firstly, make sure that you water the plant well.
Prepare the new container, ensuring that it is large enough to accommodate the existing root system of the plant.
Place a little of the growing medium at the base of this new container.
Remove the plant from the pot it came in and position it in the new container on top of the growing medium you have placed there.
Make sure that once the rest of the pot is filled, the salix will sit at the same depth as it sat at in its previous pot.
Next, add more of the growing medium around the sides of the existing root system and firm this into place gently, making sure that you do not compact the medium too much, taking care to avoid the creation of air pockets.
Finally, water in the salix; watering deeply whilst ensuring that excess water can drain away freely.
Consider adding a moisture-retaining mulch of homemade compost, wood chip or other organic matter around the top of the container, but make sure not to mound this around the trunk at the base of the plant.
Potted Willow Care
Place your container in a location with full sun.
Keep your salix well watered during the growing season, making sure that the medium does not dry out, but also making sure that the conditions do not become waterlogged.
Pruning will depend on which variety you are growing.
In general, only light maintenance pruning is required for tree types, but some shrubby types can be cut back harder on occasion to promote the growth of decorative stems.
Look out for pests like aphids, caterpillars, willow leaf beetles and sawflies, and be aware of fungal diseases.
Pot up your salix into a slightly larger container with a new growing medium every 2-3 years, especially when growing a standard tree type.
