Flower of the Week: Crepe Myrtle
Crepe Myrtle (Lagerstroemia indica) is a very common ornamental plant in the Eastern and Southern US. The species has dramatically varied forms, with dwarfed varieties only 2-4 ft (0.6-1.2 m) tall and arboreal varieties as tall as 27 ft (8 m).
Crepe myrtle can be grown in large green belts or hedgerows, planted in gardens as specimen trees, or potted and pruned as flower balls. They tolerate air pollution well and can be planted in mining zones and big cities.
Petals are the most characteristic part of crepe myrtles. There are 6 petals on each crepe myrtle flower, and they come in various colors like white, coral pink, rosy red, red, fuchsia, etc.
Small flowers will form a 0.2-0.6 in (7-20 cm) long conical blooms. A crepe myrtle petal has a long base and a loose, wrinkled top. When blooming, the entire inflorescence impresses as a whole and stands out easily.
A close look at crepe myrtle flowers’ details.
The flower’s name, crêpe myrtle, traces its origin to the petals, too, because the petals bear resemblance to colorful crêpe paper. People also occasionally spell it as crape myrtle, which is also acceptable.
Crêpe paper in orange and yellow.
Crepe myrtle originated from East Asia and was introduced to America in 1747. The plant’s cultivation history in America is as long as the history of the United States.
Because they require little care and the flowering season lasts long during summer and fall, their popularity soared shortly after their introduction and they were widely grown in the Southern US.
In 1950, American horticulturists brought the seeds of Japanese crepe myrtle (Lagerstroemia fauriei), a close relative of crepe myrtle, back from Japan, and planted them on the campus of the University of North Carolina.
The descendants of those foreign species display features such as erect tree trunks and are more cold-resistant, giving horticulturists ideas to hybridize Japanese crepe myrtle with the native crepe myrtle.
The hybridization took place in the United States National Arboretum and turned out to be a big success. A series of deeply accoladed lines of varieties have been cultivated from these offsprings, all of which are named after Native American tribes, including the famous ‘Natchez’ line.
Branches of crepe myrtle of the ‘Natchez’ line.
Decades later, geneticists employed new technology to process crepe myrtle by using chemical mutagens and Gamma-ray mutagenesis, and since then have selected and cultivated a new batch of excellent varieties, including the dark-leafed variety with dark fuchsia leaves.
Crepe Myrtle tolerates drought and heat well and doesn’t need much care, so it is a good choice for gardening beginners.
It loves sunlight, so place it outdoors in sunny spots during the growing season. Sufficient light duration also reduces the chance of powdery mildew.
When digging the planting pit, apply some bone meal as base fertilizer and mix the bone meal and soil evenly. Crepe myrtle is not tolerant of high-concentration fertilizers; over-fertilizing can result in spindling and failure to bloom. Just apply diluted liquid fertilizers once a month during its growing season, and stop fertilizing after the flower season.
Crepe myrtles of open field culture generally don’t require additional watering in an area with normal precipitation, but will need some watering in dry or excessively hot seasons. Potted crepe myrtles need a higher watering frequency that those in the open.
To make its flower season last longer, trim branch tips with spent flowers in time to promote re-budding for the next round of flowering. Proper pruning can prolong crepe myrtle’s flowering season to 100-120 days.
To keep the plant form in good shape, prune in late winter. The soils of potted crepe myrtles need to be replaced every 2 to 3 years.
Crepe myrtles after the winter pruning.
Powdery mildew and Cercospora blight are common diseases that may harm crepe myrtle. Purchasing varieties that are resistant to those diseases can prevent such problems. If your plant becomes diseased, remove the sick branches and leaves and improve ventilation.
Leaf browning is also a common problem. If it happens in spring, it’s often caused by an occasional cold spell, and usually won’t kill the plant. If it happens in summer, it’s probably caused by excessive heat and drought (common in the Southern US). Keep watering the plant in early mornings, and the symptoms should fade away.
Size: 8-20 feet (2.5-6 m) tall, treetop diameter 5-10 feet (1.5-3 m)
Hardiness: USDA Hardiness Zones 6-9
Light Duration: Full light
Soil: Sandy soil, loamy soil, or chalk soil with good drainage
Blooming Time: Summer to early fall