Plant of the Month September 2017


Published: September 16, 2017

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Posted on 16.09.2017 |
Added in Plant of the Month

Lagerstroemia

Driving through the south of France this summer, I spotted many delightful Lagerstroemias along roadsides and in gardens, reminding me of the largely dismissive attitude we have towards them here in the UK. Providing elegant structure and many vibrant flowers, I wondered if it was time for us to review our concerns. Eminent writers and manuals such as W. J. Bean and Hillier have previously referred  to an unreliability to flower in our climate and requiring more sun than we receive. However well established shrubs such as those at Kew Gardens and Wrest Park put on magnificent displays most years, and I would argue that if you are looking for a hardy unusual shrub, Lagerstroemia  or ‘crepe myrtle'  might be one to try.

Native to  China and Korea, was introduced to Kew Gardens  in 1759 where it was first grown under glass as it was suspected to need protection from frost, however it has since grown successfully outside. It is commonly grown in France, Spain and famously in parts of North America. In recent years a lot of effort has gone into selective plant breeding for increased hardiness as well as a larger range of flower colours and length of flowering season.  

This large deciduous shrub grows to an ultimate height of 6m with a spread of 6m and is usually multi-stemmed. Lower branches reveal the softly mottled grey bark that peels and sheds each year. The common name crepe myrtle refers to both the myrtle resembling round leaves and the crinkled crêpe like flowers. The leaves are smooth edged and throughout later summer to winter they turn from a dark green through yellow, to orange and red as they drop. 
 


The mottled grey bark

Flower Close-up

The noteworthy flowers are borne on panicles at the end of the current seasons growth. These can be up to 20cm long with the flowers up to 3cm in size. Produced in a range of colours from white, pink, purple to dark red, they are characteristically crinkled and frilled.


Flowering Stem

Flower Panicle

Lagerstroemia will grow best in a sunny position with free draining soil. If you have one, a south facing wall in full sun will provide the perfect setting. Flowering  will be encouraged with somewhat drastic pruning each year, once a framework has been established, this will also help control the size of the plant in a garden setting. 


In Wrest Park

Cuttings can be taken in late spring using softwood material or in midsummer using semi-ripe growth. Take cuttings just below a node and dip in a 0.25% IBA hormone or equivalent, tip cuttings are usually the most successful and root quickest. Place cuttings into a free draining propagation compost (such as a mix of coir and perlite), water carefully and place in a propagator or inside a clear plastic bag in semi-shade. 

While relatively pest and disease free in this country, aphids may attack in late spring but usually not in large enough numbers to cause any major damage. Yearly pruning to keep the plant growth habit open will help avoid any problems of mildew. 

Throughout the UK, conditions are becoming more favourable for Lagerstroemia. That combined with new breeding from the US, means that there are likely to be cultivars suitable for many gardens over here. Flowering gaps left in the summer once shrubs such as Hydrangeas have gone over, can be gracefully filled, and with stunning bark and magnificent autumn colour, this shrub is definitely no one trick pony.