Crape Myrtle (Lagerstroemia indica)

In the heart of summer, when many shrubs are already past their prime, the Crape Myrtle is covered in clouds of wavy flowers like crepe paper, from pure white to deep purple through every shade of pink and red. It follows with a flamboyant autumn foliage, then reveals in winter a smooth, mottled bark that exfoliates beautifully: it is ornamental twelve months of the year.

Capable of flowering for a long time, even in pot or small gardens, hardy enough to thrive well beyond Mediterranean climates, and now offering varieties with green, bronze, purple or nearly black foliage, the Crape Myrtle is one of the best ornamental shrubs for bringing colour, structure and elegance to a modern garden.

The Crape Myrtle is a shrub or small tree with a typically upright then slightly spreading habit, forming a rounded crown with age.

• Mature height: 2 to 8 m depending on the variety and training method (bush, standard, small tree)
• Width: 2 to 5 m, often close to the height for free-form specimens
• Growth: medium to fairly fast in favourable conditions (warmth, well-drained soil)
• Longevity: high; old specimens can exceed 50 years

Deciduous foliage, unlike the common lilac to which it is sometimes compared.

• Leaves opposite or sometimes whorled
• Elliptic to obovate shape (2 to 5 cm long)
• Texture: leathery, slightly glossy depending on the variety
• Seasonal colour: typically medium to dark green; some modern selections have purple to almost black foliage (e.g. Twilight Magic®, Midnight Magic®, Black Solitaire®)
• Young leaves often bronze or reddish
• Autumn colours: golden yellow, orange, bright red or purple depending on climate and variety

Flowering is the main signature of the Crape Myrtle.

• Period: July to September, sometimes until October in mild climates
• Arrangement: upright terminal panicles, often pyramidally elongated (15 to 30 cm long)
• Flowers: small (3 to 5 cm), with 6 finely ruffled petals, crinkled like crepe paper
• Colours: white, pale pink, bright pink, fuchsia, crimson red, mauve, deep violet depending on the cultivars
• Stamens: numerous, with very decorative yellow anthers
• Fragrance: light to almost absent in most varieties (less fragrant than the common lilac Syringa)

Flowers form on the current year's wood, which explains the importance of pruning to stimulate flowering.

• Fruits: small brown capsules, spherical to ovoid, which dry and split open to release small winged seeds
• Seeds: fine, dark brown, dispersed by wind
• Bark: smooth on young plants, becoming satin-like with age then exfoliating in thin plates; revealing cream, beige, cinnamon or pinkish-grey tones highly decorative in winter

Lagerstroemia indica is native to the tropical and subtropical regions of Asia: China, India, Korea, Japan and Southeast Asia. In the wild, some Lagerstroemia species are found in open woodlands, forest edges, rocky areas or the banks of warm streams.

The genus Lagerstroemia was described by Carl Linnaeus, who named it in honour of his Swedish friend Magnus von Lagerström, director of the Swedish East India Company, who supplied him with numerous Asian plant specimens.

Lagerstroemia indica was introduced to Europe from the 18th century onward as an exotic curiosity. Its cultivation developed mainly in southern gardens (Italy, southern France, Spain) as the shrub requires warmth and long summers to flower well.

From the 20th century onward, numerous hybridisation programmes, notably in the United States (hybrid series with L. fauriei) and in Europe, achieved:

• increased hardiness (down to –20 °C for some hybrids)
• reduced susceptibility to powdery mildew
• new flower colours
• more compact habits for small gardens and container growing
• purple to black foliage that is highly ornamental

This is why, under the name "Crape Myrtle", one finds today both the type species L. indica and hybrids such as Lagerstroemia × fauriei and countless horticultural cultivars.

The Crape Myrtle is a plant of warmth and light.

• Ideal exposure: full sun (at least 6 hours of direct sunlight per day)
• Climate: Mediterranean, mild oceanic, or warm continental but well-sunned
• Hardiness: depending on the variety, from –12 °C to –20 °C; the rootstock is often hardier than the aerial wood
• Sensitivity: fears late frosts on young shoots, summers that are too cool and damp which can compromise flowering

In cold regions or those with short summers, prefer the hardiest varieties, very sheltered locations (south-facing wall foot, courtyard, patio) and sometimes growing in a large pot to be brought in or protected in winter.

The Crape Myrtle is fairly tolerant, but it prefers:

• Soil: deep, well-drained, light to moderately clayey
• pH: slightly acidic to neutral, or even weakly calcareous in some lines
• Soil that is fresh but never waterlogged in winter

It tolerates ordinary soils relatively well, even slightly calcareous ones, as long as they are not waterlogged. In heavy soil, adding coarse sand and compost, plus planting on a mound or slight slope, improves drainage.

Spacing: 2 to 4 m between plants depending on the variety's vigour and the desired effect (border, free-form hedge, specimen).

• After planting (first 1 to 2 years): regular watering during dry periods to keep the soil slightly fresh; do not let the rootball dry out completely.
• Once well established: the Crape Myrtle becomes moderately drought-resistant; supplementary watering during prolonged heatwaves, especially for potted specimens.
• In pots: substrate dries faster; monitor and water as soon as the surface is dry to a few centimetres, without letting water stagnate in the saucer.

• At planting: incorporate mature compost into the hole.
• Every year: add compost or well-rotted manure at the base in late winter or early spring, lightly scratched into the surface.
• Mineral fertiliser: optionally a slow-release shrub or rose fertiliser in spring, but avoid excess nitrogen which promotes foliage at the expense of flowers.

An organic mulch keeps the soil cool, reduces watering needs and gradually enriches the soil. Weed regularly around the base, especially in the first few years, to avoid competition from unwanted plants.

The Crape Myrtle flowers on the current year's wood. Regular pruning:

• stimulates vigorous, highly floriferous young shoots
• maintains a harmonious and proportionate habit
• prevents tangled branches and the "knob-headed" effect
• reduces disease risk on weakened wood

• Main period: late winter to very early spring, after severe frosts and before the resumption of growth (February–March depending on the region).
• Light summer pruning: optionally in summer to remove a bothersome or misplaced branch, but without excess.

The way to prune depends on the desired form (bush, standard, small tree).

Maintenance pruning of a bush-form shrub

1. Remove dead, broken or diseased wood at the base.
2. Thin out the centre of the bush to let in light and air.
3. Shorten the previous year's shoots to 2–4 buds (generally 20–40 cm from their base), cutting above an outward-facing bud.
4. Remove unwanted branch starts near the ground if a more open habit is desired.

Standard or small tree pruning

1. Maintain a sufficiently tall main trunk (1.80 to 2 m) and remove suckers on the trunk.
2. Form a framework of 3 to 5 main branches well distributed around the trunk.
3. Shorten secondary branches each year to promote the formation of new flowering shoots.

Avoid repeated drastic "knob-head" pruning in the same spot, which weakens the tree and creates unsightly stubs.

Sowing is possible but rarely used by amateurs as it does not faithfully reproduce the characteristics of horticultural varieties.

• Seed collection: at capsule maturity, late summer to autumn.
• Stratification: a cold period can improve germination.
• Sowing: in spring, in seed trays or pots, in a light and draining substrate.
• Limitation: high variability among seedlings; mainly interesting for selecting new specimens or for botanical species.

Cuttings are the most common method for faithfully propagating a cultivar.

Semi-ripe cuttings (summer)

1. Take in July–August tips of semi-woody shoots of 10–15 cm, preferably not yet flowering.
2. Remove lower leaves and optionally shorten remaining leaves by half to limit evaporation.
3. Dip the base in rooting hormone (optional but useful).
4. Plant in a very well-drained mix (sand + cutting compost).
5. Maintain a humid atmosphere (mini-greenhouse, ventilated plastic bag) and gentle warmth (20–25 °C) in filtered light.
6. Pot up rooted cuttings individually, then harden them off gradually.

Hardwood cuttings (winter)

1. Take in late winter segments of previous year's shoots.
2. Place in a nursery trench or pot, in a well-drained substrate.
3. Success rate is less reliable than with semi-ripe cuttings, but possible.

Some varieties are grafted onto hardier rootstocks (for example Lagerstroemia fauriei) to improve cold and powdery mildew resistance. Grafting is mainly practised by professional nursery growers (cleft grafting, budding) and rarely by amateur gardeners.

This is the main disease of Crape Myrtle in hot and humid climates.

• Symptoms: white powdery coating on leaves, deformation of young shoots, reduced flowering.
• Favourable conditions: heat + humidity, insufficient air circulation, watering on foliage.
• Prevention: choose resistant varieties, plant in a well-ventilated situation, avoid excess nitrogen and overhead watering, prune to open the branch framework.
• Treatments: sulphur sprays, potassium bicarbonate, horsetail decoctions or authorised garden fungicides if necessary.

In very damp weather, leaf spots may appear (Cercospora, etc.). Generally, damage remains limited: remove affected leaves and improve ventilation. A fungicide treatment may be considered in case of severe attack.

The Crape Myrtle is generally little attacked, but you may observe:

• Aphids: on young shoots, causing leaf curling and honeydew → black soap treatment, beneficial insects (ladybirds), water spray.
• Scale insects: on branches, especially in confined situations or in pots → brushing, white oil in winter, targeted treatment during growth if necessary.
• Various caterpillars: consuming a few leaves without major damage.

• Absence or poor flowering: often due to lack of sun, a summer that is too cool, incorrect pruning (not pruned or pruned too late), or excess nitrogen.
• Frozen branches: in harsh winters, the tips may freeze; prune dead wood in spring, the plant usually regrows from the base or lower branches.
• Chlorosis (yellowing leaves): possible in very calcareous soil with hard irrigation water; add compost, chelated iron if necessary, and improve soil life.

To extend the visual interest of the border, it can be combined with:

• Summer perennials: gauras, coneflowers, rudbeckias, daylilies, agapanthus.
• Ornamental grasses: miscanthus, pennisetums, stipa, panicums.
• Mediterranean shrubs: oleanders, rockroses, rosemary, lavender (in well-drained soil).
• Autumn shrubs: dwarf Japanese maples, fothergilla, smoke bush, which complement its beautiful autumn colouring.

Although the Crape Myrtle is primarily ornamental, it has several assets:

• Late-flowering: fills the summer flowering gap in many gardens.
• Nectar source: its flowers attract bees and pollinators, especially in warm weather.
• Structural plant: thanks to its tree-like form, it provides light shade and height.
• Four-season plant: flowers in summer, flamboyant foliage in autumn, decorative bark in winter.

The main categories are:

• Tall varieties (4–8 m): for specimen planting, groves, avenues.
• Medium varieties (2–4 m): for free-form hedges, large borders, small gardens.
• Dwarf or compact varieties (1–2 m): ideal in pots, small gardens, front of borders.

A few frequently available cultivars (non-exhaustive list; availability varies by nursery):

• 'Dynamite': brilliant bright red flowers, dark green foliage turning bronze and red in autumn, vigorous habit.
• 'Twilight Magic®': dark purple foliage, abundant bright pink flowers, good disease resistance, compact habit.
• 'Midnight Magic®': very dark, almost black foliage, contrasting bright pink flowers, ideal for small gardens.
• 'Black Solitaire®': black-purple foliage, bright pink to red flowering, compact upright habit.
• Dwarf series (Muscogee, Tonto, etc. in various catalogues): numerous US cultivars, relatively hardy, often resulting from L. indica × L. fauriei crosses.
• White forms: cultivars with pure white flowering, very luminous (often sold as "white Lagerstroemia indica").
• Mauve/purple forms: cultivars with mauve or deep violet flowering, much appreciated in contemporary gardens.

You will find Crape Myrtles at:

• Specialist nurseries for ornamental shrubs and Mediterranean plants.
• Garden centres and large garden retail chains (usually classic varieties in containers).
• Online nurseries and sites specialising in summer-flowering shrubs: wide selection of colours, habits and hardiness levels.
• Plant markets and garden festivals, where you may encounter collector growers offering original varieties.

Before purchasing, check:

• the stated hardiness (minimum temperature tolerated)
• the expected mature height
• the flower and foliage colour
• the susceptibility to powdery mildew if you garden in a humid climate