How to grow Duranta
This tender member of the verbena family is something of a rarity in the UK, though well known in its native America. In a tropical habitat (its natural home), the fast-growing, evergreen shrub can become a small tree in just a few years and spreads enthusiastically. So much so, in fact, it is now considered an invasive weed in frost-free places such as Hawaii, Australia, and South Africa. Our chillier climes mean this isn’t a problem in the UK, where it is best grown as a conservatory or greenhouse plant. The rapid growth rate (it will grow from a tiny plug plant to a flowering shrub within one growing season) also means it can be used as that rarest of things – an annual shrub.
Duranta is grown for its slightly weeping, elegant habit, attractive sprays of phlox-like, scented purple flowers in summer, and (occasionally in our climate) golden yellow fruits in autumn. It is worth noting that these are highly toxic to people and animals. Birds, however, may eat them with no ill effects.
It’s also useful to point out that mature specimens will develop long, sharp thorns. Fortunately, this plant can be propagated very easily from cuttings, making it easy to replace once it reaches this distinctly less lovable stage.
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 Duranta
Position - Indoors: full light with shade from the hot, midday sun
Outdoors: a sunny, sheltered spot out of the wind
Compost - A loam-based compost such as John Innes No. 3
Soil - If growing as annual bedding, giving it a rich, loamy, moist yet well-draining soil will help it reach full potential within one growing season.
Flowering Period - Summer
Hardiness - Warm temperate, rated H1C (minimum temperature of 5-10°C)
To grow duranta in a container, pot up in spring and place in a temperate conservatory or greenhouse. You may wish to leave it here permanently, in which case, you may need to position some shade netting to intercept the midday summer sun. Another option is to move outdoors for the warmer months, perhaps to enjoy as part of a patio container display or to plunge, container and all, into an exotic planting scheme. Remember also the option to treat duranta as annual bedding (discarding it at the end of one growing season), in which case it may be planted directly into the soil.
While it struggles with colder temperatures, duranta has no trouble with extreme heat, so can be a good choice for those sunbaked spots in the full glare of the sun where other plants can struggle. Neither is salty air a problem for this plant, making it a good choice for sheltered coastal spots.
If your duranta will be switching between indoors and out in this way, remember to gradually acclimatise it to life outside rather than making a sudden move. For the first few days leave it out during the daytime only, returning indoors at night. Although somewhat tedious this ‘hardening off’ process is worth the effect, being highly effective at preventing tender plants going into ‘shock’. As temperatures drop towards the end of the growing season, return your duranta to its warm, protected environment. In terms of timing the moves, it pays to get to know the average temperatures in your area as well as keeping an eye on the thermometer. To give you a general idea, May is when the UK average temperature starts to remain above 5°C, and October when it drops back down. Remember though that these are UK averages and there will be regional variation.
How to plant Duranta
· With such a fast growth rate duranta will be quick to fill its pot, so contrary to what we usually advise starting with a large container is fine. Just ensure there are plenty of drainage holes in the bottom.
· It can be a good idea to fill and plant this in situ to save yourself the trouble of moving once full.
· Use a good quality loam-based potting compost with some slow-release feed mixed in. Sometimes these are already present in the compost, others you will need to add your own (check the description on the bag).
· Start by partially filling the pot with compost; enough so that when placed on it the upper surface of the root ball is about 3 centimetres lower than the top of the pot.
· Infill all the space surrounding the root ball with compost, firming down with your fingers then adding a little more so the plant is held tight.
· Pick up the container and lightly tap 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).
· For planting in the garden, dig the soil area removing any large stones and weeds and breaking up any lumps. Rake level and firm with your heels. Rake level again. Now is the time to add well-rotted organic matter – manure, garden compost, or leaf mould are all ideal.
· Water your duranta well and allow it to drain before planting.
· Dig a hole twice the width 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.
What to plant with Duranta
Turn your conservatory into a bright, colourful oasis by growing duranta with companions such as such as streptosolen, brugmansia, plumbago, dipladenia, jacobinia, abutilon and cestrum. If you plan to move these outside for summer, make the climbers portable by training them up an obelisk inserted into their container.
How to care for Duranta
Pruning and Deadheading
Officially, duranta falls under RHS pruning group 1, which means it requires little or no pruning other than a light tidy in spring, removing any dead, diseased, damaged, or misplaced growth. However, when it is grown in a warm, indoor environment it can become too large for its allotted space, in which case a hard, restrictive prune in late winter can be a good idea. As well as maintaining a more manageable size, this also generates a rush of new growth which is the best for fruiting and flowering.
Flowers may be deadheaded to encourage a second flush.
Watering
Duranta is thirsty when grown in a container and can be watered freely throughout the growing season. Try to avoid the compost drying out completely, being aware that this can happen in as little as 24 hours during the height of summer (and sometimes even less for very full containers). You can mist if you like, though this is not essential – duranta is equally happy in both dry and humid conditions. Water much more sparingly in the cooler months, i.e., just enough to prevent the compost drying out completely.
In the open ground, give duranta a good soak on initial planting and then a handful more times after this. From then on (particularly if that original soaking is ‘sealed in’ with a layer of mulch), it should be self-sufficient in all but prolonged periods of hot dry weather.
Feeding
In a container, get off to a flying start by making sure you use a good quality, loam-based compost with some slow-release feed mixed in, then apply a fortnightly dose of balanced liquid feed throughout the growing season. Repotting every few years into fresh compost is beneficial, and when this is no longer feasible carry out a topdress each spring. Simply scrape away the top 5 centimetres of compost and replace with fresh, settling everything in with a good soak of water. Always remember to include slow-release feed in your fresh compost.
In the open ground, no feeding should be required providing you have healthy, fertile soil. On leaner soil, work a scattering of blood, fish and bone or general purpose feed into the soil before you mulch in the early stages, and then again midseason if necessary.
Cold Protection
Duranta hails from much warmer climes than ours and will not survive a UK winter outside. Follow our advice above for choosing the best spot to achieve optimum growth.
Pests and Diseases
Outdoors, duranta tends to be trouble-free. Indoors, the usual issues of whitefly, spider mite, and mealybug can crop up. Keeping indoor plants as healthy as possible is the key to warding off problems, and by this we mean proper ventilation, adequately spaced plants (for good air flow), keeping everything well-watered and fed, and repotting into larger containers when necessary. A summer spell outdoors can be effective in clearing up any issues, and thoroughly cleaning the indoor environment every winter can 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 Duranta
The vigorous habit of duranta means it roots very easily from cuttings. This is a good way to ensure replacement plants for those which may be becoming too large or thorny, or are being treated as annuals. The best method is to take semi-ripe cuttings in summer:
· Look for current year’s growth which is firm and woody at the base while still flexible at the tip. You’re aiming for a cutting of 10 centimetres or less (any longer and they are more likely to dry out and fail). For best results, choose stems where the leaf nodes are close together rather than far apart.
· Using a sharp knife or secateurs, sever the cutting from the plant and put in a plastic bag straight away to keep it from drying out.
· Fill a pot (or several, if you have a lot of cuttings) with a perlite-heavy compost mix (at least 50% perlite).
· Trim the end of the cutting to just below a node (point at which leaves grow).
· Remove lowest leaves, leaving 2-4 on the cutting.
· If the remaining leaves are large, cut them in half with a sharp knife to reduce water lost through transpiration.
· 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.
· Place in a propagating unit with gentle bottom heat if you have one, or covered with a plastic bag on a windowsill if not (out of direct sunlight). Note that bottom heat will dramatically increase your chances of success.
· 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.
· Gently remove rooted cuttings and pot them into individual pots. Grow on in a warm, protected environment such as a heated conservatory or greenhouse, or a windowsill until they are large enough to be used as above.
* Many plants carry Plant Breeders Rights and cannot be propagated for commercial purposes.
Common Duranta Questions
· What is the difference between Duranta repens and Duranta erecta?
Nothing, these are two names of the same plant. Repens was the original species name before it was updated to erecta. Though there are 30 different species, this is the one with the greatest garden value and which you are most likely to find offered for sale. Of this, there are many cultivated forms, offering features such as white or bicolour flowers, variegated leaves, and thornless stems.
· How quickly does duranta grow?
Expect it to put on up to 50 centimetres per year.
· Why has my duranta become lanky and sparse?
This can be a result of insufficient light. Cut it back hard in late winter and, if possible, move to a sunnier spot.
