How to grow Lagerstroemia
Also known as crepe myrtle, lagerstroemia is a genus of deciduous and evergreen shrubs and trees from the warm climes of Asia and Australia. Although there are around 50 species, the most widely cultivated is the deciduous Lagerstroemia indica from China – now a common sight across southern Europe (particularly Italy, southern France, and Spain) and southern US. It is grown for its summer to autumn explosion of brightly coloured flower panicles, with their characteristic crinkled, crepe-like petals, and also offers good autumn colour and attractive peeling bark. In warm places it can become a sizeable tree, however in our cooler climate it can be expected to remain more shrub sized.
In the UK, crepe myrtle tends to grow best in milder places such as the more southerly and easterly regions, or coastal gardens and protected urban spots (a good pollution tolerance makes it well suited to city life). Further north or inland, extra care will be needed to ensure winter survival.
Lagerstroemia is a member of the loosestrife family. It grows quickly and flowers from a young age.
Zantedeschia is a genus of flowering plants from the family Araceae and is native to southern Africa. With a rich history dating back to the Ancient Romans, these deciduous or semi-evergreen perennials have been used as a symbol of celebration. Zantedeschia was Named after Professor Giovanni Zantedeschia, an Italian botanist.
There are two main forms of Zantedeschia: hardy and tender. Hardy forms of the plant can be grown outdoors, enjoy moist soil and full sun or partially shaded conditions - these are known as Arum lilies. Tender forms of Zantedeschia prefer being grown in containers or pots and should be brought inside over the winter - these are known as Calla lilies.
With tuberous flora in all colours from whites, yellows and oranges to deep reds and purples, Zantedeschias are not to be overlooked in any garden, as long as they have sufficient sunlight to grow in.
Ready to learn more about growing Zantedeschia? Read on for all there is to know...
Key Information
Soil pH
Position
Hardiness
Where & when to plant Lagerstroemia
Position - Outdoors: full sun with shelter from wind. Growing against a hot, sunny wall results in the best flowering.
Indoors: full light.
Soil - Moderately fertile and well-draining.
Flowering Period - Summer to autumn
Hardiness - Overall hardy, mostly rated H4 (i.e., -5 to -10°C), though growth and flowering can be severely checked by exposure to cold weather, particularly on young specimens. The wood becomes hardier after sun ripening.
Lagerstroemia usually comes as a container grown plant. In theory this means it can be planted at any time of year, though best results are achieved from a spring planting which gives it time to settle in before facing the challenges of a UK winter. Wait until all risk of frost has passed. This varies from region to region though tends to be around late May.
Planting can also be carried out in summer, though be prepared to water regularly. Autumn is an option if you have an unusually mild microclimate and can offer free-draining soil.
Lagerstroemia enjoys a sunny, south-facing spot which is protected from northerly and easterly winds. Planting against a wall or building is a good idea, or in a sheltered gravel garden, courtyard, coastal garden, or sunbaked bank.
Lagerstroemia dislikes being moved, so take your time to choose a ‘forever’ spot when planting. Give it plenty of room too – lagerstroemia looks best when left to grow unrestricted and will suffer if routinely hacked back to fit a too-small-space.
Smaller forms of lagerstroemia do well in a large container, and in fact this can be a good way to enjoy the plant if you get harsh winters. Move it in a conservatory or greenhouse for the cooler months, or even keep it in there all year round if you like.
How to plant Lagerstroemia
· For planting in the ground, prepare the area by removing any weeds. Mix in a generous amount of organic matter such as manure or garden compost (this is especially needed at the base of walls, where the soil can be dry and poor).
· Water the plant well and allow to drain.
· Dig a hole twice the size of the root-ball.
· Place the plant in the hole, ensuring the top of the root ball sits level with the surface of the soil. Too low and the plant may rot, too high and the roots can dry out.
· Backfill with soil and firm in gently with your foot.
· Soak well with water.
· Mulch around the base with well-rotted organic matter such as manure or garden compost.
· For planting in containers (remember, smaller forms are best for this), first choose an appropriately sized pot just a few centimetres larger than the rootball. Ensure there are plenty of drainage holes.
· It can be worth filling large containers in situ to save yourself the trouble of moving once full.
· Water the plant well and allow to drain.
· Use a good quality potting compost with plenty of horticultural grit mixed in, and, if not already present in the compost (check the description on the bag) some slow-release fertiliser granules.
· Start by partially filling the pot with compost; enough so that when placed on it the top of the roots sits about 3cm lower than the top of the pot.
· Infill all the space surrounding the roots with compost, firming down with your fingers then adding a little more so the plant is held tight.
· Pick up the pot (if you can!) and lightly tap on the potting bench or ground a few times to help further settle the compost around the plant.
· Soak well with water.
· A mulch with horticultural grit will look attractive and help to prevent a ‘cap’ or crust forming on the top of the compost (something container plants can suffer due to the artificial nature of their watering).
What to plant with Lagerstroemia
In its adopted Mediterranean home, lagerstroemia mixes seamlessly with companions such as lavender, plumbago, hibiscus, salvia, pelargonium, cistus, and lavender. Some of these will need help to get through a UK winter, though the rich, heady, holiday-invoking results make the effort well worth it.
How to care for Lagerstroemia
Pruning and Deadheading
Lagerstroemia is classed as RHS pruning group 1, meaning it requires little or no pruning other than the occasional removal of dead, diseased, damaged, or badly placed growth in spring. Lagerstroemia has a naturally attractive shape which is likely to be spoilt by excessive pruning. They key is to allow adequate space for it to grow untouched – find out the expected height and spread of your chosen form so you may choose a spot accordingly.
In some countries, lagerstroemia is traditionally pruned hard each year to a set height (pollarded), to restrict its size and generate a profusion of flowering growth. Although widespread, the practice is not advisable, and has even been dubbed ‘crepe murder’ by some experts. For one thing, it spoils the natural form of the plant, and for another, the resulting rush of new growth is both less hardy and more likely to snap under the weight of the heavy blooms than mature wood.
Watering
Water your lagerstroemia regularly for the first year or so in the ground while its roots become established. After this it is drought-tolerant and largely self-sufficient in all but the most prolonged periods of hot, dry weather. When watering, avoid overdoing it by allowing the top few centimetres of soil to dry out each time. Wiggle your finger down into the soil to check this.
If you are growing lagerstroemia in a container water freely throughout every growing season, being aware that in the height of summer your pots may need watering as often as once a day. Scale right back in the cooler months, to just enough to prevent the compost drying out completely.
Feeding
On healthy, fertile soil, an annual mulch of well-rotted organic matter should provide sufficient nutrients for your lagerstroemia. This has the added benefit of suppressing weeds, locking in moisture, and – if done in the autumn – insulating the roots during winter.
Container-grown plants rely more on the gardener for nutrition. Get off to a flying start by making sure you use a good quality potting compost, then throughout the growing season (March to September) apply a liquid feed once a month. This can be a balanced feed at first, switching to a high potash version in summer to boost flowering (tomato feed is ideal for this). Remember to repot into a slightly larger pot with fresh compost every few years, and once this is no longer feasible switch to an annual topdress instead. In spring, scrape away the top 5cm of compost and replace with fresh, remembering to mix in a little general-purpose slow-release feed.
Cold Protection
Planted in a warm, sheltered spot such as those suggested above, lagerstroemia should overwinter outdoors without the need for special measures. Everywhere else it is advisable either to provide winter protection, such as one of these handy fleece jackets, or to overwinter plants in a covered environment such as an unheated greenhouse or conservatory. This is especially important for younger specimens – new, unripened growth is more susceptible to cold damage than mature wood.
A thick mulch in autumn will insulate the roots and is recommended regardless of location.
Pests and Diseases
Outdoors, lagerstroemia tends to be trouble free. Indoors, the usual issues of spider mite and whitefly can crop up. Keeping conservatory plants as healthy as possible is the key to warding off problems, and by this we mean proper ventilation, adequate spacing (for good air flow), keeping everything well-watered and fed, and repotting into larger containers when necessary. Thoroughly cleaning the indoor environment every winter can also help to remove overwintering populations of pests.
Where infestations do take hold, try introducing biological controls (often sachets or tubes containing miniscule natural predators), or in the worst cases, remove the affected plant/s altogether.
How to propagate Lagerstroemia
Lagerstroemia is best propagated by cuttings in late spring or summer, ideally with bottom heat:
1. Take 10-centimetre cuttings of healthy non-flowering shoots. Snip off just above a bud using sharp, clean secateurs.
2. Place in a clean plastic bag in which to transport the cuttings back to a potting bench or garden table.
3. Fill a container with a well-draining compost mix.
4. Trim the end of the cutting to just below a node (point at which leaves grow).
5. Remove the lowest third of the leaves.
6. Insert the cuttings into the compost and water lightly. Several cuttings can be put in the same container if there is enough space to do this without them touching.
7. Place in a propagating unit with bottom heat if you have one, or covered with a plastic bag on a warm windowsill if not (out of direct sunlight). If using a plastic bag, remove it a couple of times a week for around ten minutes. This will ensure the cuttings remain well-ventilated and don’t rot.
8. Keep the cuttings misted and occasionally watered until they root. You will know this has happened when roots emerge out of the bottom of the container.
9. Gently remove rooted cuttings and pot them into individual pots. Grow on in a protected environment such as a conservatory, greenhouse, or that windowsill again, before potting on or planting as above.
* Many plants carry Plant Breeders Rights and cannot be propagated for commercial purposes.
Common Lagerstroemia Questions
