Non-agressive Wisteria

(Question)

Hello,
I recently moved into a century home in North Toronto area. There is a pergola on top of a deck in the backyard about 20ft from the house. I’d like to have a wisteria there. However, I don’t want to risk the wisteria’s root work it’s way into the house foundation or lifting the interlock in the backyard. I want to grow it in a big planter near the deck (see picture) and train it to climb onto the pergola.
I have read that some Asian species are very aggressive and the roots might burst the planter in a few years.

Can you suggest some species that are not too aggressive, that can grow well in a big planer? Do i need to worry about fallen seeds germinating nearby?
Please suggest as many species as possible for consideration.

It would be lovely if you can give suggestions of other vines that can fill the pergola and lattice well. Something with white or light colour, fragrant flowers (bonus if edible). I am considering honeysuckle but i heard it’s invasive as well ?! And I believe the Northern bush variety suggested in your site here does not climb?

Many thanks for your help!

(Answer)

Thank you for contacting Toronto Master Gardeners. Based on the photo that you provided and the directional orientation, it appears that the area is shaded for most of the day given the north facing exposure and the massive deciduous tree just over the fence in your neighbour’s yard. Your preferred vine Wisteria to grow over your pergola on the deck is not an ideal candidate for the following reasons:

  • Wisterias require full sun. Although they will grow in partial shade, they likely won’t flower
  • Wisterias are big woody, aggressive vines which grow to be very heavy such that they can topple whole structures like fences and pergolas
  • They have an extensive root system which will not thrive in a planter over time nor will the roots like being exposed to the elements in the winter, even if the planter is a large one

Outlined below are several good perennial vine alternatives that will thrive in light shade (shade all or most of the day with some sun filtering through to ground level) or full shade. Given you wish to plant the vine in a container, it is best to choose a plant at 1-2 zones hardier than your area to improve the likelihood of successful overwintering in its pot outdoors. The hardiness zone for Toronto is 6 and the following plants are hardier:

Climbing Hydrangea (Hydrangea anomala ssp. peteolaris) – Zone 4-9

  • grows in light to full shade in moist to well-drained soil; grows slowly to 9-12m in length; prominent lateral branches cling with aerial roots; large flat-topped clusters of fragrant white flowers bloom from early Spring to late Summer; Caution: another woody vine which needs a sturdy trellis

Virginia Creeper (Parthenocissus quinquefolia) – Zone 3-8

  • hardy, native vine that grows quickly in sun or shade in fairly moist soil; can reach over 12m in length; clinging rootlets provide the support to attach to walls or structures; green foliage turns scarlet red in October with blue-black fruit in September

Boston Ivy (Parthenocissus tricuspidata ‘Veitchii’) – Zone 3-8

  • grows in any light from full sun to full shade in moist to well-drained soil; grows 20m in length; green foliage turns scarlet red in October

Jackman Clematis (Clematis x Jackmanii) – Zone 3-9

  • a hardy clematis that grows in full sun and partial shade. Roots need shade or mulch to keep them cool; showy deep purple flowers that bloom from July through to September

Goldflame Honeysuckle (Lonicera x heckrotti) – Zone 5-9

  • grows in full sun to partial shade in moist soil; 4-6m in length; climbs by twining stems; fragrant tubular pink-purple flowers with yellow centres bloom from late Spring until early Fall; not the best blooming results if if planted in partial shade

Another approach is to plant several vines together in the planter especially if one them is an annual vine so that you get blooming and coverage in the first years while the perennial vine gets established. Annual vines that grow well in light shade are Black-Eyed Susan Vine (Thumbergia alta) offering a variety of flower colour options including yellow, orange, violet blue & white and Sweet Potato Vine (Ipomoea batatasBlackie’) with burgundy foliage and (I. batatas ‘Margarita’) with chartreuse foliage

For your reference, links related to selecting and planting a vine in a large pot:

https://landscapeontario.com/climbing-vines

https://www.torontomastergardeners.ca/askagardener/native-climbing-flowering-vines/

https://gardenmaking.com/overwinter-perennials-in-pots/