Rebellion and Chaos and Freedom Contained: How to Grow Willows Indoors
Who is the Willow, and why does she weep?
The willow has a complex relation with human cultures—a liminal figure, standing on the cusp of life and death, it sometimes unwitting victims from either side and placing them on the other. Whether it features as an ephemeral figure and others a boorish swamp man, the willow serves as a subversion of the rule, a symbol of rebellion.
And this isn’t just in the world of mythology and symbology. The willow can often withstand shoreline conditions no other plants can handle (when water levels rise and dip, they expose the shores to drought, drowning, and free-flowing contaminants), often making them quite a lonely (sometimes eerie) figure along the shore, this perspective perpetuated by its trailing “weeping” figure. While some people loved its hardiness and defiance of erosion, its proliferation and defiance against the elements can also make this plant a difficult to contain in an urban environment. Hanging over the water and spilling over the edge, branches of this tree can easily snap off and spread downstream, propagating easily from their stems, becoming a kind of weed in environments that allow it to proliferate and spread.
“Good” or “bad” aside, this tree, with its specific features, represents an unfettered will to live. For the people who love it and let it grow, the willow is a source of beauty and resilience—its chemical compounds (like salicylic acid) not only protects plant cells against rot and damage, but also serves as a beauty product (cleaning and protecting healthy skin) and a natural aspirin (in fact, aspirin is literally a processed for of salicylic acid, called acetylasylic acid). However, it might be difficult to contain a willow in, let’s say, a bonsai, because the building of a bonsai is an art that requires careful planning and order to resemble nature. And the willow (though able to grow in this environment) can often throw off these designs by culling a branch or growing in unruly directions.
The willow proves, over and over, that it’s not a plant that can be easily contained.
How to grow a willow indoors
All this to say, the willow is a great plant, with its easy-going, resilient, beautiful aesthetic, and maybe even its practical uses and cultural background—but it will often feel as though you’re playing by its rules, not the other way around. Outside, a willow can survive being cut all the way back (in fact, this is a common gardening practice, called coppicing), but an indoor willow can be far more conversational than other houseplants, constantly changing, fast-growing, and extremely unapologetic in their needs.
That being said, once you’ve found your step and the plant has found its footing, the willow can be an excellent companion in even the most urban environments.
Every plant to its own place
Members of the salix (willow) family exist in most climates, with a few (rarer) tropical willows nestled amongst the temperate varieties. However, these trees are trees, and as anyone who’s tried to grow a bonsai will understand, keeping them in a smaller container doesn’t necessarily diminish the amount of water and light (and nutrients) this plant will need. Keeping a large plant small through its container takes a lot of maintenance.
On the other hand, there can be ways to mitigate this particular difficulty. For example, there are dwarf varieties, which are considered slower growing than some of their relatives. For example, the dwarf arctic willow (Salix purpurea 'Nana') and the dappled pink willow (Salix integra ‘Hakuro Nishiki’) are both popular additions to home gardens because they only get to around 5 feet tall on a good day; in fact, the dappled willow is popularly sold grafted onto the base of another tree in order to give it a bit of a boost, so to speak (like permanently stitched stilettos or stilts). Both can survive a wide range of conditions (as temperate plants) and are also far less demanding than the classic weeping willow in a home environment.
Pot Size
This doesn’t mean that a dwarf willow variety will enjoy tight quarters. Willow roots grow quite quickly, just the same as its canopy. And, left unchecked, they can break free through the holes of the pot. While the willow’s roots aren’t particularly woody or thick, meaning its space constraints will not be defined by the thickness of its roots, it’s also considered quite a hungry and thirsty plant (meaning the water in a smaller pot will dry up quite quickly). It may be best to start off with a roomier space for the tree to establish good roots, especially since over-watering a small plant in a large pot (this happens because the water in a large pot isn’t getting used up by the smaller plant and isn’t allowed to evaporate completely between waterings) isn’t as much of an issue. The general suggestion is to get a pot that matches the size of the tree’s canopy in width.
Soil
As mentioned, the willow is a hungry plant, and needs a great deal of nutrients from the soil. Though willows in the wild are surprisingly accepting of quite a diverse and often despicable array of soil conditions, this is because the willow can send its roots outward in search for what they need, and because they do not have the extra stressors of relying on human care (as well as the reduced light, air circulation, and exposure to coddled houseplant pests). In a contained environment, the willow will need well-draining soil with lots of balanced fertilizer (preferring slightly acidic pH).
Water
This is quite simple. Willows require water. LOTS of water.
Water
Okay, maybe not that simple. Willows need a lot of water, and as a general rule, it’s better to overwater the plant than to underwater it; even though wild, mature willow trees are known to withstand periods of drought, a container willow cannot thrive on the same level of neglect.
But, while it is better to overwater the plant, the key here is that it is possible to overwater, especially without the proper light and the proper air circulation (ie. in a home environment). If a willow is being kept indoors, it will have decidedly less light (no matter how big the windows), and so it’s better to let the surface of the soil dry slightly between watering. It’s also best to make sure the soil isn’t sopping wet (with proper drainage) when it’s being watered, to ensure the roots are getting enough air.
Light
This is the main pain point for willows that are grown in an indoor environment. No matter how big the windows, it’s often not enough. Though not providing the plant with full hours of direct sun will not kill it (trees outside can survive the shaded areas of a forest and the unfortunate hours of the arctic sun), less sun can make the tree more susceptible to external pain points like aphids, spider mites, and environmental changes (like watering issues).
When we were growing willows in our east-facing condominium window, we found that it was impossible to provide enough light for the willow to thrive, especially through the five-month Canadian winter of consistent 9-5 sun. The tree grew extremely slowly, gaining less than five centimeters of growth through the whole season. It also had a single encounter of spider mites. However, the plant still did quite well otherwise, especially when we installed bright LED lights (followed by full-spectrum grow lights).
Though it may be more difficult than growing a willow outside (and a great deal slower), the plant can do surprisingly well with supplemental light and a frequent wipe-down of the leaves (to remove dust, which can impede the plant’s light intake, and to catch pests early).
Humidity
Although humidity might help in periods of drought (thriving in about 50-80% humidity), this shouldn’t be much of a concern for a willow tree that’s watered regularly.
Common Pests
Willows are quite hardy against pests, but even in the wild, aphids are a painful nemesis for this plant, causing black fungal spots on its trunk and havoc for its pollinators. And in closed quarters, they are more susceptible to pests like spider mites, which no longer need to battle their natural predators for survival. However, both of these pests can be detected quickly and dealt with swiftly if the surface of the plant is frequently wiped, as mentioned previously.
How to propagate a willow from cuttings
Propagating a willow isn’t a problem. Or, rather, propagating a willow is so easy that it has become a problem to some outdoor biomes, with unwanted clones washing up everywhere along the waterside. In fact, some people claim that putting a willow cutting with other propagations can help other plants root faster (though we’ve never tested this ourselves).
While the best time to take a cutting of these plants is supposed to be around February or May (before the plant exerts all its stored energy on its leaves and flowers), it’s definitely possible to take cuttings throughout the year, usually with the most success being cuttings of at least six nodes in (around 6-8”). After the shoot roots, it should be put in a well-draining substrate that’s kept consistently moist until the plant is properly established.
How to grow or gift a willow
With all the potential trouble and fuss it takes to grow such a prolific plant indoors, is it worth all the effort?
For most people, the easiest course of action would be to simply plant this tree in a yard outside. It’s definitely hardy enough, and usually doesn’t raise much hell. That is, if you can get yourself a private outdoor space. And if you’re willing to watch such an unruly plant spread the way it wishes.
Yet, there’s something interesting about growing a container willow.
Across time and space—from Babylon to ancient Greece, and from China or Korea to England and America—willows were used to cure inflammation and fevers. In Japan, the willow is a symbol of subordinate obedience, but in Korean culture and Confucian ideology, the willow’s weeping form allows it to survive and subvert the powers that try to contain it—perhaps this idea is most aptly portrayed in the Korean mythology of the willow (Ryuhwa, or willow flower), risking her life to rescue her sisters and escaping her captive to birth the new founder of the Korean kingdom of Goguryo
Maybe it’s this concept of persistence and defiance that makes this plant (in many cultures, from Japan to Korea to China) a symbol of separation between loved ones, either as a reminder, or a parting gift. While the willow is a lonely figure along the shoreline, it’s also a reminder that you can grow at the end of hardship, and you can meet at the end of separation.
In the same way, the willow can be difficult to grow indoors or in containers, because it’s a tree that isn’t one to be contained. However, learning how to grow with this plant and caring for its love of life (whether it’s in the close quarters of a home, or the luxury of a backyard) can be a reminder that in the hardest times, there’s always a way and a reason to thrive.
If you’re ready to bring home a plant that thrives on its own terms, the willow is waiting. From a dwarf variety for your windowsill to a young tree destined for your backyard, it’s more than greenery. It’s a living reminder that persistence often grows in unexpected places. Discover your willow at Bookmark Plant Store and see where its roots will take you.