'Summer Red' flowering gum
Plants I love

Flowering gum

The flowering gums have been dazzling this summer. The massive scarlet blooms and the brilliant heads of orange beat Christmas baubles for decorative value hands down. Flowering gums make cheerily flamboyant street trees and look amazing planted with other vibrant flowers in a total colour onslaught that makes a drag queen look dowdy by comparison.

The sight of these beauties colouring up our Christmas and New Year is relatively recent and due to sterling work by horticulturists. First on the list of those to toast is Stan Henry. Henry was frustrated that he couldn’t grow Western Australia’s glorious red-flowering gum in his Queensland garden. It would look like it was growing, offering tantalising anticipation, only to produce insipid flowers before dropping dead.

The problem was the weather. The WA native, Corymbia ficifolia, like so many other Western Australian plants, is no fan of humidity. Henry’s brilliant idea was to try hybridising the west Australian with one of his local swamp bloodwoods, Corymbia pthychocarpa. The successful result, now grown on grafted rootstock, is marketed as the ‘Summer’ series of flowering gums: ‘Summer Red’; ‘Summer Snow’, which has creamy blooms and ‘Summer Beauty’, which has peachy-pink flowers.

The Summer series trees get to 6m. Recent cultivars add size options to the flowering gum menu. ‘Baby Orange’, for instance, is a small tree, around 3m by 3m, with a dense canopy completely covered through summer and into autumn by brilliant orange blooms. ‘Baby Orange’ and its generation of cultivars aren’t hybridised but instead are the best selections of C. ficifolia, grafted onto a rootstock that allows them to thrive on the east coast. Siblings include ‘Calypso Queen’, with watermelon-pink flowers to a neighbour-screening 4m high and wide; and ‘Lollypops’ with candy-pink flowers on a tree that gets to 5m or so.

All of these flowering gums do best in full sun, and don’t like frost until they are well established. They aren’t needy garden plants, but to perform at their best they do require gardeners to get handy with the pruners. Tip pruning newly planted trees every couple of months is optional but will help develop a dense canopy. The single don’t-miss job is an annual prune as the flowers start to fade. You can start this early if you like by cutting flowers for the house – they look fantastic but don’t last. The aim is to prevent the tree putting energy into producing gumnuts, which has the effect of reducing flowering the following year. You can also control the height of the tree with this prune, removing up to 30 per cent of the plant if necessary. Follow the prune with a dose of low-phosphorus fertiliser designed for natives to promote new growth and more flowering next summer.

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5 thoughts on “Flowering gum

  1. Natalie Filatoff says:

    I love the way gardening and horticulture never stand still. Enthusiasts are always exploring vibrant possibilities, and scientists are constantly discovering the secrets of plants and creatures already familiar to us on one level. Thanks for keeping us in the loop with ideas from the canopy, while we have our hands in the soil.

  2. Nigel Quarmby says:

    Hello Robin,
    Thanks for Scarlet Fever [and to Stan]. Do you think any of these would flourish in the Bowral/Mittagong area?

    • Robin Powell says:

      Hi Nigel
      I think the big problem would be to get them established as they are very sensitive to frost damage in the first five years. Do you see any mature ones doing well in your area? You might get some good advice from local nurseries, who may also be able to sell you more mature trees that could cope with your winters. Good luck!

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