At first glance, it may seem counter intuitive to grow wisteria indoors. The deciduous climbing vine generally grows best when planted in the ground and sufficiently supported. It requires up to 6 hours of full sunlight a day and benefits from a moist fertilizer.
However, when you also consider that, despite its sun requirements, outdoor wisteria is at risk of drying out, it only needs in-depth fertilization once a year, and it benefits from having supports in place, it actually makes a lot of sense to grow wisteria indoors in a container.
You can more easily control its moisture level, more accurately maintain an ideal soil pH between 6.0 and 7.0, and handle the plant's annual pruning without getting down and dirty outside.
If you decide to go down this path for your wisteria, here are some things to consider about indoor, container growing.
1. Size Matters
Wisteria is a large and hardy vine, a relative of the pea family. Chinese wisteria and Japanese wisteria varieties and cultivars can grow to 25 feet in height. This fact alone may deter many home gardeners from considering planting wisteria in a container. Wisteria are highly invasive, so unless you are willing to constantly, prune, state or otherwise manage it, don't attempt to grow it in a container.
Alternatively, when choosing your cultivar from a gardening store or other source, you can opt for a variety that's reputation isn't so large. However, even that won't change the fact that wisteria is a vine and vines love to spread out. So, if you're not up for the job of maintaining it, don't attempt it. This is not a set it and forget it kind of plant for the indoors.
2. Get a Large Pot or Container
The ideal container for a wisteria is a commercial grade pot or planter that’s both big and heavy enough to contain the vine and necessary supports. It should also be made from a material that will help retain moisture and temperature.
The large, spreading root system of this climbing vine is what supports healthy growth of roots. Since you won't always be able to see the root system, it's important to get a proper container so that you can be confident it's treating the roots right, even if you can't always tell at a glance.
Earthenware pots are traditional and often used in the garden, but they dry out easily. Stone and ceramic pots or containers are better at holding in moisture and soil temperature. If the plant will be moved, look for a container that you’ll be able to handle, as well as dolly, lifting apparatus, or other mechanisms.
Starting off a wisteria vine in a pot or container that’s two to four times the size of the one it originally came in from the nursery will give the home gardener time to search for a more appropriately sized and more permanent container.
3. Vine Supports are Critical
Without proper support, this creeping vine will take over the surroundings, climb up walls, get into gutters, poke through cracks in the foundation – even causing the foundation and concrete to crack and buckle.
Propping the plant up with supports won't just train the wisteria to grow in a way that showcases its pendulous blooms, but the supports also train it to grow vertically effectively containing its spread.
Use wood stakes or trellis or arbor that's made from non-treated wood and will fit in the container. The container may also be situated next to a brick wall – or trellis or arbor, and the wisteria can be trained to grow against this backdrop. For the brick wall, use rows of wire attached 4-6 inches from the wall.
Although the container-grown wisteria requires more than the average amount of care and hard work, the results in years to come will be well worth the effort.