Tree of the Week: The spectacular red-flowering gum

This article was originally on a blog post platform and may be missing photos, graphics or links. See About archive blog posts.

Good morning, Kent Desormeaux. LA Land is pulling for you on this beautiful spring Saturday. For those of you doing some gardening today, or maybe taking a trip to the nursery, today’s thought of the day, from Pieter Severynen: Embrace the unpredictable. Without further ado,

Pieter Severynen’s Tree of the Week:

The red-flowering gum — Corymbia ficifolia (a.k.a. Eucalyptus ficifolia)

The red-flowering gum is not for those who like their street trees lined up military fashion or who love uniformity and predictability. This is an extreme individualist for gardeners who like to gamble. The flowers may be crimson red, orange, salmon, cream or white, but the color cannot be predicted and there is a seven-year wait for the first bloom.

The tree flowers when it wants to, usually in late spring, but also intermittently throughout the year. Some trees bloom heavily every year, others every other year. Propagation is usually by seed, and the resulting more or less round-headed tree may be anywhere from 20 to 40 feet tall and 15 to 50 feet wide. (Grafting a branch onto another eucalyptus rootstock for a more certain outcome is possible but difficult.)

The tree easily hybridizes with the larger Eucalyptus calophylla, making the outcome even more variable. Some mature trees sport a huge lignotuber, a conspicuous swelling at the base of the trunk, wherein dormant vegetative buds wait to regenerate the tree after a fire; others do not.

The tree is absolutely spectacular in bloom, when the foot-long flower clusters form hemispherical domes, or corymbs, which are borne elevated above the leaf canopy. A moderately fast grower, the red-flowering gum looks best where there is some coastal influence. Eventually it grows into a very dense roundhead, with rough, longitudinally furrowed gray bark on the trunk. The leaves are broad and glossy, 3 to 7 inches long, darker on top than underneath. After flowering, clusters of showy, inch-wide, 1-to-3-inch-long, hard, urn- or pipe-bowl-shaped gum-nut fruit are so numerous that they may pull the branches down.

The tree does well in urban conditions of air pollution, drought and compacted soil, but it does not like lawn watering. Its faults are many, if not as numerous as its virtues. Branches are somewhat susceptible to breakage because of poor crotch formation. When stressed the trunk starts bleeding black sap, or kino. Like most Eucalyptus species the tree is subject to borers and psyllids, which are controlled to some extent by imported predators, and to leaf spots and crown gall. The tree is not in fashion right now.

The red-flowering gum is native to a very small area of south coastal western Australia. In 1995 the botanical powers that be decided to transfer some 90 Eucalyptus species, including E. ficifolia, into the newly created Corymbia genus; trade acceptance of the new name is not yet universal.

Thanks, Pieter.

Your thoughts? Comments? E-mail story tips to Peter.Viles@latimes.com