So many canna plants from breeders that were bred with different traits; they come in a range of heights, in Australia canna heights are often classed as Pixie, dwarf, medium and tall growing cannas.
I class my cannas as Short -up to and including one meter tall.
Medium -above one meter to two meters tall.
Tall -from two meters up to two and a half meters tall.
and Giant -above two and a half meters tall.
These heights are measured from the ground to the top of the flowers. I use a metal curtain rod with 10 cm increments to obtain accurate plant measurements.
Regardless of the height that your plants have the potential to reach will depend on a few factors being met, such as soil, fertilizer, sun, and watering and of course if planting occurs early or late in the season.
When planted out in late winter or early in spring the canna plants will grows and produces its first lot of flowers, it probably won’t be anywhere near its full potential height yet though, in good conditions as the season progresses that flowering plant will produce more shoots that will grow taller than the first flowers and so on, in a single division planted out I usually see three different flowering height the third being the maximum height that particular variety has the potential to reach.
Example let’s say I plant a division of a short growing pixie canna such as the cultivator Beatrix which only seems to be found in Australia, Beatrix is well known here as a short grower, planted late winter Beatrix will flower mid spring at approx 40 cms tall, by the end of summer and well into late autumn Beatrix has reached around 1 meters tall, this is the maximum height I’ve ever had her flowers reach, not quite a true pixie canna anymore in my eyes, this come down to growing conditions mainly watering and an open sunny position and manure fertilizing.
If this now clump of Beatrix is left alone and not dug etc, then next year’s Beatrix’s first flowers will appear a bit earlier if the season is the same as last and the first flush will be taller as long as I apply ample watering etc, reason being is because the clump is now well established with a good build up of energy reserves and the how to grow canna plants to their maximum height has been met.
The main indicator for canna height is watering.
A through soaking every 2 weeks will greatly help cannas reach their full height potentials.
When kept on the dry side cannas won’t reach their full height potential.
Potted cannas generally grow shorter and stay smaller in height when compared to in ground plants.
Short growing or Dwarf cannas are nothing new, they have been around for ages and these heritage plants are still widely grown today.
I class my short cannas in height as up to one meter tall.
Dwarf Cannas view the low dwarf plants up to one meter tall.
One of the shortest canna plants I grow reach 80 cms tall, this height is measured from the ground to the top of the flower. There are not many cannas that are true short plants; some of my dwarf plants come in green, brown and variegated foliage. Canna Ruby Cole pictured below is one of the short height cannas, it reaches a maximum of 80 cms tall, I've never had it grow any taller.
This is the size most of my canna plants fall into.
I class my medium cannas in height from above one meter to two meters tall.
There are many to choose from.
Cultivator Rosever just reaches 1.5 meters with dark brown bronzed foliage.
There are not as many tall cannas. Pictured above is canna Italia it dates back to 1883, it can grow up to 2.1 meters tall.
I class my tall cannas in height from above two meters to two and a half meters tall.
Most of the really tall canna plants above two meters tall are also suitable for planting in or around backyard ponds.