A Gardening Journal

Glory Bush

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My glory bush has been in bloom all Winter.  Then again, it's in bloom much of the Summer, too.  Glorious, indeed.  The flowers are nearly three inches in diameter.  Each has the impact of an orchid, if not the endurance: A couple of days, and the petals drop.  New buds open steadily, and when the shrub is enjoying the heat and sun of Summer, the show can be seen from clear across the garden.

 

With only five petals, the flower's simplicity is a sharp contrast to its coloring.  

 

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But look more closely.  Each of the pink stamens is tipped with a scimitar-like structure whose toothy ridges seems to be channeling either a saw blade or the suckers of octopus. 

 

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Glory bush:  Beauty with attitude.  I love it!

 

 

Here's how to grow this ravishing tropical shrub:

 

Latin Name

Tibouchina semidecandra

Common Name

Glory Bush

Family

Melastomaceae, the Melastoma family.  Plants in this family of, primarily, shrubs and trees, are known for their purple flowers.  Some are infamous noxious weeds in the tropics, but none of those are in the Tibouchina genus.

What kind of plant is it?

Evergreen shrub.

Hardiness

Zones 8 - 12

Habit

In Zone 8 and 9, a die-back shrub that blooms by late Summer.  In Zones 10, 11, and 12, a shrub of almost rhododendron-like proportion and impact—but which remains in bloom much of the year, not just for two weeks in Spring or early Summer.  Sigh.

Rate of Growth

Fast.

Size in ten years

In a frost-tree climate, to fifteen feet tall and wide.  Plants are rarely permitted to grow to full-height; see "How to handle it" below. 

Texture

In optimum conditions of sun, warmth, rich soil, and ready moisture, growth can be dense and even heavy, like that of a rhododendron.  In somewhat less generous circumstances, growth is still eager, floriferous, and lengthy, but is often sprawling and open.

Grown for

its foliage:  The pointed and fuzzy leaves have prominent longitudinal veins. 

 

its buds:  The fuzzy buds, as well as the petioles that display them in loose clusters, are red and prominent.  The shrub is a show even before a single flower has opened.

 

its flowers:  Remarkable, and your first experience of them is likely to be a life-long memory.  (My first sighting was the Summer of 1976, near the Coit Tower in San Francisco.)  Five-petaled flowers are about three inches in diameter.  They are an irridescent blue-violet darkly veined in purple, and are so vivid as to seem fluorescent.  A complicated and showy accent of white pistils and pink stamens is worth closer inspection: the anthers (the pollen-bearing structure at the tip of each stamen) is scimitar-shaped, with ridges that look like octopus suckers. 

 

its precocious vigor and ease of propagation:  Cuttings of glory bush root easily, and are usually in bloom before they reach a foot tall.  

Flowering season

Where the shrub is hardy, heavy flowering can be continuous from Spring through Fall; sporadic flowering can occur year-round.  As a cutting-grown annual, in bloom from Spring through frost.  As a die-back shrub, in bloom by mid- to late-Summer, and continuing until frost.

Color combinations

Glory bush is so vivid in itself that it seems most comfortable when neighboring plants provide pastels.  They can be of any hue, but pink, white, and dusty burgundy are fool-proof.  The Kool Aid hues of Tibouchina are already too strident to be combined with other saturated colors, let alone with those in the hot spectrum of yellow, orange, and red.     

Partner plants

Tibouchina needs to be associated with plants with strongly contrasting textures in softly coordinating colors.  The fuzzy, pointed, and strongly-veined leaves are at their best in the company of foliage that's either ferny and feathery, or gigantic.  Go extreme, at either end:  Ferns; ferny leaves (Japanese maples, e.g.); and leaves that are doubly or even triply pinnate (e.g., Aralia, Mimosa, Jacaranda)—or smooth-and-huge foliage from plants such as bananas, Tetrapanax, cannas, elephant ears, and castor beans.  Extra points if your leaves are huge and shiny: Magnolia grandiflora, say.

 

Or combine with the spear-shaped leaves of grasses, phormiums, and iris.

 

Bonus points if the leaves themselves can provide color harmony.  This will usually mean burgundy—Hibiscus acetosella, say, or purple-leaved cultivars of castor bean, phormium, mimosa, and canna—but foliage with white variegation will improvise with the white pistils of the Tibouchina flowers. 

 

With flowers as pulsating and proud as those of glory bush, neighboring plants that rely on flowers for impact had better be extraordinary if they're not to be overwhelmed.  Choose flowers with shapes that are distinctly different, in sizes that are much smaller or (if possible) much larger, and in arrays that are contrastingly spiky or pendulous.  Orchids as well as erythrinas, with small pink or white flowers in long sprays.  Ornamental grasses with plumes that are white, dusty rose, or pink.  Woody species and cultivars in the pea family—such as Acacia and Indigofera—whose small flowers can be dangling or erect. 

 

Choose plants that will be in bloom when the Tibouchina is.  Wisteria may be the perfect partner in color (white, pink, rose, purple), bloom size and shape (small and asymmetric), and pendulous bloom array—but the vine is only in flower in early Spring.  Tibouchina won't be in flower then unless you're gardening at the mildest end of wisteria's range, Zone 9. 

Where to use it in your garden

Where hardy, Tibouchina is used as casually and obliviously as Northerners use big rhododendrons:  As bulky in-fill or as big foundation shrubs for blank walls and corporate campuses.  Where it's not hardy, Tibouchina is a prized container plant, positioned for maximal impact so its flowers can stun cold-climate visitors who, heretofore, had thought that no flowers could be more ravishing than peonies.

Culture

When growing in ground, good soil in full sun.  In containers, rich soil and full sun. 

How to handle it: The Basics

Tibouchina blooms only at the tips of new growth, so do what you can to keep the plant active, which, inherently, means production of more new growth. Unless you're gardening in subtropical or tropical climates, full sun and all possible heat is a must.   

 

Plant in soil that's rich in organic matter, and top-dress with compost, too.  You could even water with fish-emulsion.  Tibouchina branches readily, even from old wood, so never hesitate to pinch new growth if—or, rather, when—the shrub becomes leggy.  The entire shrub can be lopped back to stumps in Spring, and will resprout and bloom that same season. 

How to handle it: Another option—or two?

Tibouchina is exciting even as a cutting-grown annual, so can be used in containers or even (I suppose) as bedding. 

 

The shrub is easy to overwinter.  Bring into shelter before frost, and cut back as needed for easy handling.  Unless sheltered in warmth and heat, water only sparingly until longer days of February and March.  Then increase watering in pace with new growth, but not in advance of it.  After the shrub has really woken up for the new season, prune severely to get rid of often awkward and angular branches that were formed last year; this pruning also spurs plenty of young new shoots.  If they haven't set buds already, pinch them as soon as they have three sets of leaves, to encourage even more tips and, therefore, even more flowers.  Fertilize monthly, and, if you have room for a larger shrub, repot before you set the pot back outside after frost danger has past.

Quirks or special cases

If your climate is hot enough, your site sunny enough, and your season long enough, you should be able to train Tibouchina as a standard.  Stake one main branch to the vertical, and when it's as tall as you'd like, pinch it so it starts to bush out.  Keep pinching, as well as pruning off side-branches lower down, and you'll create a standard that blooms all season.

 

In my experience, the climate in New England isn't hot enough for T. semidecandra to produce more than shrubby growth.  So far, then, no Tibouchina standards for me.  I might try T. granulosa, instead:  It's a small tree, not a bush, and, like all Tibouchina species and cultivars, blooms at the tips of new wood. 

Downsides

None.   

Variants

The Tibouchina genus is big—with about 350 species of shrubs and trees, all subtropical or tropical.  Only a few besides T. semidecandra have entered even specialist plant lists, let alone popular horticulture.  T. clavata (T. elegans) is similar in habit to T. semidecandra, but the leaves are wide enough to have inspired the common name of bear's ears.  T. granulosa is roughly the size of a dogwood, and thrives in southern Florida and California.  T. grandifolia has much larger leaves but much smaller flowers—but the flowers are in racemes that can be almost delphinium-like in their size and impact.  It's easy in southern California, but, in great contrast with T. semidecandra, can be a disappointment as a container plant or cutting-rooted annual in cooler climates.  It needs more heat than T. semidecandra, and isn't nearly as accommodating of less than ideal conditions during overwintering; I write from exasperating experience.  T. lepidota 'Variegata' is a small and somewhat prostrate shrub, with leaves neatly edged in cream; T. granulosa 'Gibralter' seems similar.     

 

Availability

On-line and at retailers.

Propagation

By cuttings. 

Native habitat

Tibouchina demidecandra is native to Brazil.

 

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