(Question)
Please could you recommend a cluster of rose varieties and ideally well established ones, for a small border, with their stature kept below chest height, for sheltered part-shade aspect, USDA Zone 5b ? To compliment and boost the display, could you please suggest a handful of flowering perennial plants as their companions right through the flowering season that will still permit good air circulation? Thanks
(Answer)
How lovely to be planning a border. For a list of nurseries that may be able to help, I refer you to the Landscape Ontario website. https://landscapeontario.com/
If you are interested interested in native plants the the Halton Master Gardeners have a list of native plant nurseries which we can recommend: https://haltonmastergardeners.com/2020/03/28/native-plants-nurseries-in-ontario/
Below is a link to the growing requirements for roses which normally require 6 to 8 hours of full sun a day.
Since you mention a “sheltered part shade aspect” here is a great article from the American Rose Society on growing Roses in Partial Shade : https://www.rose.org/single-post/2018/04/27/growing-roses-in-partial-shade.
You may wish to grow roses that are grown on their own root stock such as the Canadian Shield series. Most Floribunda and shrub roses will meet your height requirement.
You may also wish to consider some design elements such as do you prefer hot colours, red, orange, yellow or cool colour like pink, blue, whites? The article below deals with general elements such as colour, texture, repetition, balance, etcetera.
These following links provide information specifically in regards to companion planting for roses. https://www.thespruce.com/companion-planting-for-roses-1403041
Furthermore the New York Botanical Garden has a great website for companion planting for roses : https://libguides.nybg.org/companionplantingroses plus https://fallbrookgardenclub.org/companion-plants-for-roses/
Good luck with your border.