Does Wisteria Grow in a Big Pot or Is It Better Grounded?

Container Size and Material

• Wisteria is a fast-growing plant with spreading roots. You need a 20- to 30-gallon container if the plant will be growing there for an extended period of time. Smaller containers will require frequent root pruning to control the growth.

  Wisteria can grow into a very large standard with an impressive trunk and root system. Containers must be sturdy enough so the roots do not crack through. A half whiskey barrel or a large concrete container is suitable. Terracotta is not recommended due to its tendency to crack during the winter months. Plastic fades quickly and becomes brittle when exposed to freezing temperatures. Any container must have several drainage holes in the bottom.

Planting and Watering

• Wisteria likes well-draining acidic soil. A good potting mixture is equal parts coarse sand, peat moss and general potting soil. The peat moss adds acidity while the sand provides the required drainage. Wisteria in a container needs more water than one in the ground, but does not like soggy soil. Water thoroughly and let the soil dry completely between waterings.

Fertilization and Pruning

• An acid-loving blooming plant fertilizer, such as an azalea formula, is desirable for feeding wisteria. A timed-release pelletized fertilizer can be applied every three to six months at the rate of 1 teaspoon per gallon of container size. Wisteria blooms better when pruned. Using a high-nitrogen fertilizer will lead to excess foliage and no blooms.

  Pruning is necessary to encourage abundant blooms. Prune at any time during the growing cycle to keep the plant in bounds or to train it. Keep in mind that new buds formed during the summer produce next year's flowers. If severe pruning is desired, do so immediately after blooming. Deadheading faded blooms keeps your wisteria from producing messy seedpods.

Considerations

• If your plant is in full sun, is fertilized and watered correctly and still isn't blooming, you may need to root prune it. Remove it from the container and prune off 1/3 of the root ball, then re-pot it with fresh soil. The shock may spur blossoming. Seed-grown wisteria may never bloom, so it is best to buy a grafted plant or grow your own from cuttings.

  Dropping wisteria blooms are messy, so choose your plant's site with that in mind.