The Four o'clock plant is Mirabilis jalapa, and it has been grown in the UK for around 200 years. The name comes from the flowerswhich have a habit of opening in the afternoon, so that explains the name '4 o'clock plant'. This is a tuberous plant and tubers or bulbs are available for sale, plants can also be grown from seed.
A plant with many names, Mirabilis jalapa is not only known as the Four o'clock plant, but also as the Marvel of Peru, Blue jasmine, Belle de Nuit (pretty by night)
Originally from South America,Peru and surrounding countries mirabilis jalapa is a frost tender perennial, often grown in conservatories and greenhouses during the Victorian era, and making a big comeback in the UK today although usually as an annual.
Fairly low growing to around 2ft , mid green ovate leaves, the real attraction of the Four o'clock plant is the fragrance of the flowers, in the afternoon as the temperature begins to drop the flowers open, trumpet shaped, pink, red white but with fragrance that fills the garden. And just to add to the wonder of these plants some are variegated, or at least they have stripes, yellow and red, pink and white and so on.
You can grow the Four o'clock plant as a summer flowering bedding plant, try it in a container on a patio or simply in the garden gorder in a sunny position. They are readily available for sale in nurseries through spring.
Propagation of Mirabilis Jalapa
Propagation is from seed or from root division. Plants can be divided in winter when dormant, seeds can be sown in a greenhouse or cold frame in late winter to early spring, seed germination of Mirabilis Jalapa is fairly easy, in fact they will even self seed, once germinated and hardened of they are ready to plant out, once the danger of frosts is over.
Growing conditions and care
Growing outside in the UK is OK, just find a warm sunny position, however the tubers need a reasonably dry dormancy otherwise they have a tendency to rot. Often grown in pots or containers so that optimum conditions can be maintained.
If you are planting Mirabilis Jalapa in the ground, find a warm sunny position and a humus rich soil, plant tubers at the end of March through to mid April, around 5cm deep and 20 - 30 cm apart.
If the soil is well drained you can try to overwinter by mulching with a blanket of straw, many gardeners lift the tubers or bulbs and store in a cool dry position over winter ready for planting out in spring
In spring once new growth starts you can begin watering, try a liquid seaweed fertiliser with Mirabilis Jalapa for great results.